codeine/aspirin/carisoprodol (Rx)

Musculoskeletal Pain

1-2 tab/cap PO QID for up to 2-3 weeks

Musculoskeletal Pain

<16 years: Safety & efficacy not established

16 years or older: As adults; 1-2 tab/cap PO QID for up to 2-3 weeks

Contraindicated (3)

• abrocitinib

  abrocitinib and aspirin both increase anticoagulation. Contraindicated. Antiplatelet drugs, except for low-dose aspirin (=81 mg qDay), during the first 3 months of treatment are contraindicated.

• alvimopan

  alvimopan, codeine. receptor binding competition. Contraindicated. Alvimopan is contraindicated in opioid tolerant patients (ie, those who have taken therapeutic doses of opioids for >7 consecutive days immediately prior to taking alvimopan). Patients recently exposed to opioids are expected to be more sensitive to the effects of alvimopan and therefore may experience abdominal pain, nausea and vomiting, and diarrhea. No significant interaction is expected with concurrent use of opioid analgesics and alvimopan in patients who received opioid analgesics for 7 or fewer consecutive days prior to alvimopan.

• dichlorphenamide

  dichlorphenamide increases levels of aspirin by unknown mechanism. Contraindicated. Coadministration of dichlorphenamide with high-dose aspirin may increase salicylate levels. Anorexia, tachypnea, lethargy, and coma reported.

Serious - Use Alternative (73)

• acrivastine

  acrivastine and codeine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate

• amisulpride

  amisulpride and codeine both increase sedation. Avoid or Use Alternate Drug.

• apalutamide

  apalutamide will decrease the level or effect of carisoprodol by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug. Coadministration of apalutamide, a strong CYP2C19 inducer, with drugs that are CYP2C19 substrates can result in lower exposure to these medications. Avoid or substitute another drug for these medications when possible. Evaluate for loss of therapeutic effect if medication must be coadministered.

• asenapine

  asenapine and codeine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate

• asenapine transdermal

  asenapine transdermal and codeine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate

• avapritinib

  avapritinib and codeine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate

• benazepril

  aspirin, benazepril. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Coadministration may result in a significant decrease in renal function. NSAIDs may diminish the antihypertensive effect of ACE inhibitors. The mechanism of these interactions is likely related to the ability of NSAIDs to reduce the synthesis of vasodilating renal prostaglandins.

• benzhydrocodone/acetaminophen

  benzhydrocodone/acetaminophen and codeine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate
  
  benzhydrocodone/acetaminophen, codeine. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.
  
  benzhydrocodone/acetaminophen and carisoprodol both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate
  
  benzhydrocodone/acetaminophen, carisoprodol. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

• bremelanotide

  bremelanotide will decrease the level or effect of codeine by Other (see comment). Avoid or Use Alternate Drug. Bremelanotide may slow gastric emptying and potentially reduces the rate and extent of absorption of concomitantly administered oral medications. Avoid use when taking any oral drug that is dependent on threshold concentrations for efficacy. Interactions listed are representative examples and do not include all possible clinical examples.

• buprenorphine subdermal implant

  buprenorphine subdermal implant and carisoprodol both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate

• brimonidine

  brimonidine and codeine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate

• buprenorphine

  buprenorphine, codeine. Other (see comment). Avoid or Use Alternate Drug. Comment: Mixed opiate agonist/antagonists usually produce additive sedation with narcotics; however, in narcotic addicted pts., the antagonist activity may provoke withdrawal Sx.

• buprenorphine buccal

  buprenorphine buccal, codeine. Other (see comment). Avoid or Use Alternate Drug. Comment: Mixed opiate agonist/antagonists usually produce additive sedation with narcotics; however, in narcotic addicted pts., the antagonist activity may provoke withdrawal Sx.

• buprenorphine subdermal implant

  buprenorphine subdermal implant and codeine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate

• butorphanol

  butorphanol, codeine. Other (see comment). Avoid or Use Alternate Drug. Comment: Mixed opiate agonist/antagonists usually produce additive sedation with narcotics; however, in narcotic addicted pts., the antagonist activity may provoke withdrawal Sx.

• calcium/magnesium/potassium/sodium oxybates

  carisoprodol, calcium/magnesium/potassium/sodium oxybates. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.
  
  codeine, calcium/magnesium/potassium/sodium oxybates. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

• caplacizumab

  caplacizumab, aspirin. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug.

• captopril

  aspirin, captopril. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Coadministration may result in a significant decrease in renal function. NSAIDs may diminish the antihypertensive effect of ACE inhibitors. The mechanism of these interactions is likely related to the ability of NSAIDs to reduce the synthesis of vasodilating renal prostaglandins.

• clonidine

  clonidine, codeine. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration enhances CNS depressant effects.

• enalapril

  aspirin, enalapril. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Coadministration may result in a significant decrease in renal function. NSAIDs may diminish the antihypertensive effect of ACE inhibitors. The mechanism of these interactions is likely related to the ability of NSAIDs to reduce the synthesis of vasodilating renal prostaglandins.

• fosinopril

  aspirin, fosinopril. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Coadministration may result in a significant decrease in renal function. NSAIDs may diminish the antihypertensive effect of ACE inhibitors. The mechanism of these interactions is likely related to the ability of NSAIDs to reduce the synthesis of vasodilating renal prostaglandins.

• hydrocodone

  hydrocodone, carisoprodol. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

• dacomitinib

  dacomitinib will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. Avoid use with CYP2D6 substrates where minimal increases in concentration of the CYP2D6 substrate may lead to serious or life-threatening toxicities.

• diazepam intranasal

  diazepam intranasal, codeine. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

• eluxadoline

  codeine, eluxadoline. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Avoid coadministration with other drugs that cause constipation. Increases risk for constipation related serious adverse reactions. .

• fentanyl

  fentanyl, codeine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration with other CNS depressants, such as skeletal muscle relaxants, may cause respiratory depression, hypotension, profound sedation, coma, and/or death. Consider dose reduction of either or both agents to avoid serious adverse effects. Monitor for hypotension, respiratory depression, and profound sedation.

• fentanyl intranasal

  fentanyl intranasal, codeine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration with other CNS depressants, such as skeletal muscle relaxants, may cause respiratory depression, hypotension, profound sedation, coma, and/or death. Consider dose reduction of either or both agents to avoid serious adverse effects. Monitor for hypotension, respiratory depression, and profound sedation.

• fentanyl transdermal

  fentanyl transdermal, codeine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration with other CNS depressants, such as skeletal muscle relaxants, may cause respiratory depression, hypotension, profound sedation, coma, and/or death. Consider dose reduction of either or both agents to avoid serious adverse effects. Monitor for hypotension, respiratory depression, and profound sedation.

• fentanyl transmucosal

  fentanyl transmucosal, codeine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration with other CNS depressants, such as skeletal muscle relaxants, may cause respiratory depression, hypotension, profound sedation, coma, and/or death. Consider dose reduction of either or both agents to avoid serious adverse effects. Monitor for hypotension, respiratory depression, and profound sedation.

• givosiran

  givosiran will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sensitive CYP2D6 substrates with givosiran. If unavoidable, decrease the CYP2D6 substrate dosage in accordance with approved product labeling.

• hydrocodone

  hydrocodone, codeine. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

• ibuprofen

  ibuprofen decreases effects of aspirin by Other (see comment). Avoid or Use Alternate Drug. Comment: Ibuprofen decreases the antiplatelet effects of low-dose aspirin by blocking the active site of platelet cyclooxygenase. Administer ibuprofen 8 h before aspirin or at least 2-4 h after aspirin. The effect of other NSAIDs on aspirin is not established.
  
  ibuprofen increases toxicity of aspirin by anticoagulation. Avoid or Use Alternate Drug. increases risk of bleeding.

• ibuprofen IV

  ibuprofen IV increases toxicity of aspirin by anticoagulation. Avoid or Use Alternate Drug. increases risk of bleeding.
  
  ibuprofen IV decreases effects of aspirin by Other (see comment). Avoid or Use Alternate Drug. Comment: Ibuprofen decreases the antiplatelet effects of low-dose aspirin by blocking the active site of platelet cyclooxygenase. Administer ibuprofen 8 h before aspirin or at least 2-4 h after aspirin. The effect of other NSAIDs on aspirin is not established.

• isocarboxazid

  isocarboxazid increases toxicity of codeine by unknown mechanism. Avoid or Use Alternate Drug. Risk of hypotension, hyperpyrexia, somnolence, or death; separate by 14 d.

• ketorolac

  aspirin, ketorolac. Either increases toxicity of the other by pharmacodynamic synergism. Contraindicated.

• ketorolac intranasal

  aspirin, ketorolac intranasal. Either increases toxicity of the other by pharmacodynamic synergism. Contraindicated.

• lesinurad

  aspirin decreases effects of lesinurad by unspecified interaction mechanism. Avoid or Use Alternate Drug. Aspirin at doses >325 mg/day may decrease lesinurad efficacy. Aspirin doses 325 mg/day or less (ie, for cardiovascular event prophylaxis) does not decrease lesinurad efficacy and can be coadministered.

• linezolid

  linezolid increases toxicity of codeine by unknown mechanism. Avoid or Use Alternate Drug. Risk of hypotension, hyperpyrexia, somnolence, or death; separate by 14 d.

• lisinopril

  aspirin, lisinopril. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Coadministration may result in a significant decrease in renal function. NSAIDs may diminish the antihypertensive effect of ACE inhibitors. The mechanism of these interactions is likely related to the ability of NSAIDs to reduce the synthesis of vasodilating renal prostaglandins.

• lonafarnib

  lonafarnib will increase the level or effect of carisoprodol by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug. Lonafarnib may increase the AUC and peak concentration of CYP2C19 substrates. If coadministration unavoidable, monitor for adverse reactions and reduce the CYP2C19 substrate dose in accordance with its approved product labeling.

• macimorelin

  aspirin, macimorelin. unspecified interaction mechanism. Avoid or Use Alternate Drug. Drugs that directly affect the pituitary secretion of growth hormone (GH) may impact the accuracy of the macimorelin diagnostic test. Allow sufficient washout time of drugs affecting GH release before administering macimorelin. .

• measles, mumps, rubella and varicella vaccine, live

  aspirin, measles, mumps, rubella and varicella vaccine, live. Mechanism: unspecified interaction mechanism. Avoid or Use Alternate Drug. Risk of Reye's Syndrome with combination; avoid salicylate use for 6 wks after vaccination.

• methotrexate

  aspirin increases levels of methotrexate by decreasing renal clearance. Avoid or Use Alternate Drug. Caution should be exercised when salicylates are given in combination with methotrexate. Risk for drug interactions with methotrexate is greatest during high-dose methotrexate therapy, it has been recommended that any of these drugs be used cautiously with methotrexate even when methotrexate is used in low doses.

• methylene blue

  methylene blue and codeine both increase serotonin levels. Avoid or Use Alternate Drug. If drug combination must be administered, monitor for evidence of serotonergic or opioid-related toxicities

• metoclopramide intranasal

  codeine, metoclopramide intranasal. Either increases effects of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Avoid use of metoclopramide intranasal or interacting drug, depending on importance of drug to patient.
  
  carisoprodol, metoclopramide intranasal. Either increases effects of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Avoid use of metoclopramide intranasal or interacting drug, depending on importance of drug to patient.

• mifepristone

  aspirin will decrease the level or effect of mifepristone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• mitotane

  aspirin will decrease the level or effect of mitotane by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• moexipril

  aspirin, moexipril. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Coadministration may result in a significant decrease in renal function. NSAIDs may diminish the antihypertensive effect of ACE inhibitors. The mechanism of these interactions is likely related to the ability of NSAIDs to reduce the synthesis of vasodilating renal prostaglandins.

• nalbuphine

  nalbuphine, codeine. Other (see comment). Avoid or Use Alternate Drug. Comment: Mixed opiate agonist/antagonists usually produce additive sedation with narcotics; however, in narcotic addicted pts., the antagonist activity may provoke withdrawal Sx.

• olopatadine intranasal

  carisoprodol and olopatadine intranasal both increase sedation. Avoid or Use Alternate Drug. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment.

• olopatadine intranasal

  codeine and olopatadine intranasal both increase sedation. Avoid or Use Alternate Drug. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment.

• ozanimod

  ozanimod and codeine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Avoid or Use Alternate Drug. Because the active metabolite of ozanimod inhibits MAO-B in vitro, there is a potential for serious adverse reactions, including hypertensive crisis. Therefore, coadministration of ozanimod with drugs that can increase norepinephrine or serotonin is not recommended. Monitor for hypertension with concomitant use.

• pemetrexed

  aspirin increases levels of pemetrexed by unspecified interaction mechanism. Avoid or Use Alternate Drug. Interrupt dosing in all patients taking NSAIDs with long elimination half-lives for at least 5d before, the day of, and 2d following pemetrexed administration. If coadministration of an NSAID is necessary, closely monitor patients for toxicity, especially myelosuppression, renal toxicity, and GI toxicity.

• pentazocine

  pentazocine, codeine. Other (see comment). Avoid or Use Alternate Drug. Comment: Mixed opiate agonist/antagonists usually produce additive sedation with narcotics; however, in narcotic addicted pts., the antagonist activity may provoke withdrawal Sx.

• perindopril

  aspirin, perindopril. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Coadministration may result in a significant decrease in renal function. NSAIDs may diminish the antihypertensive effect of ACE inhibitors. The mechanism of these interactions is likely related to the ability of NSAIDs to reduce the synthesis of vasodilating renal prostaglandins.

• phenelzine

  phenelzine increases toxicity of codeine by unknown mechanism. Avoid or Use Alternate Drug. Risk of hypotension, hyperpyrexia, somnolence, or death; separate by 14 d.

• prasugrel

  codeine will decrease the level or effect of prasugrel by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Co-administration of opioid agonists delay and reduce absorption of prasugrel and its active metabolite presumably by slowing gastric emptying; consider the use of a parenteral anti-platelet agent in acute coronary syndrome patients requiring co-administration of opioid agonists

• probenecid

  aspirin decreases effects of probenecid by acidic (anionic) drug competition for renal tubular clearance. Avoid or Use Alternate Drug. Aspirin decreases uricosuric action of probenecid.

• procarbazine

  procarbazine increases toxicity of codeine by unknown mechanism. Avoid or Use Alternate Drug. MAOIs may potentiate CNS depression and hypotension. Do not use within 14 days of MAOI use. .

• quinapril

  aspirin, quinapril. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Coadministration may result in a significant decrease in renal function. NSAIDs may diminish the antihypertensive effect of ACE inhibitors. The mechanism of these interactions is likely related to the ability of NSAIDs to reduce the synthesis of vasodilating renal prostaglandins.

• ramipril

  aspirin, ramipril. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Coadministration may result in a significant decrease in renal function. NSAIDs may diminish the antihypertensive effect of ACE inhibitors. The mechanism of these interactions is likely related to the ability of NSAIDs to reduce the synthesis of vasodilating renal prostaglandins.

• rasagiline

  rasagiline increases toxicity of codeine by unknown mechanism. Avoid or Use Alternate Drug. Risk of hypotension, hyperpyrexia, somnolence, or death.

• selegiline transdermal

  selegiline transdermal increases toxicity of codeine by unknown mechanism. Avoid or Use Alternate Drug. Risk of hypotension, hyperpyrexia, somnolence, or death.

• selinexor

  selinexor, codeine. unspecified interaction mechanism. Avoid or Use Alternate Drug. Patients treated with selinexor may experience neurological toxicities. Avoid taking selinexor with other medications that may cause dizziness or confusion.
  
  selinexor, carisoprodol. unspecified interaction mechanism. Avoid or Use Alternate Drug. Patients treated with selinexor may experience neurological toxicities. Avoid taking selinexor with other medications that may cause dizziness or confusion.

• sodium oxybate

  codeine, sodium oxybate. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.
  
  carisoprodol, sodium oxybate. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

• sufentanil SL

  sufentanil SL, codeine. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration may result in hypotension, profound sedation, respiratory depression, coma, and death. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.
  
  sufentanil SL, carisoprodol. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration may result in hypotension, profound sedation, respiratory depression, coma, and death. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

• ticagrelor

  codeine will decrease the level or effect of ticagrelor by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Co-administration of opioid agonists delay and reduce absorption of ticagrelor and its active metabolite presumably by slowing gastric emptying; consider the use of a parenteral anti-platelet agent in acute coronary syndrome patients requiring co-administration of opioid agonists

• ticlopidine

  aspirin increases effects of ticlopidine by pharmacodynamic synergism. Avoid or Use Alternate Drug. Enhanced risk of hemorrhage.

• tramadol

  tramadol, codeine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tramadol may reinitiate opiate dependence in pts. previously addicted to other opiates; it may also provoke withdrawal Sx. in pts. who are currently opiate dependent.

• trandolapril

  aspirin, trandolapril. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Coadministration may result in a significant decrease in renal function. NSAIDs may diminish the antihypertensive effect of ACE inhibitors. The mechanism of these interactions is likely related to the ability of NSAIDs to reduce the synthesis of vasodilating renal prostaglandins.

• tranylcypromine

  tranylcypromine increases toxicity of codeine by unknown mechanism. Avoid or Use Alternate Drug. Risk of hypotension, hyperpyrexia, somnolence, or death; separate by 14 d.

• valerian

  valerian and codeine both increase sedation. Avoid or Use Alternate Drug.

• varicella virus vaccine live

  aspirin, varicella virus vaccine live. Mechanism: unspecified interaction mechanism. Avoid or Use Alternate Drug. Risk of Reye's Syndrome with combination; avoid salicylate use for 6 wks after vaccination.

Monitor Closely (524)

• abciximab

  aspirin, abciximab. Either increases toxicity of the other by anticoagulation. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; monitor closely.

• abiraterone

  abiraterone increases levels of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Avoid coadministration of abiraterone with substrates of CYP2D6. If alternative therapy cannot be used, exercise caution and consider a dose reduction of the CYP2D6 substrate.

• abobotulinumtoxinA

  carisoprodol increases effects of abobotulinumtoxinA by pharmacodynamic synergism. Use Caution/Monitor. Muscle relaxants may enhance botulinum toxin effects. Closely monitor for increased neuromuscular blockade.

• acalabrutinib

  acalabrutinib increases effects of aspirin by anticoagulation. Modify Therapy/Monitor Closely. Coadministration of acalabrutinib with antiplatelets or anticoagulants may further increase risk of hemorrhage. Monitor for signs of bleeding and consider the benefit-risk of withholding acalabrutinib for 3-7 days presurgery and postsurgery depending upon the type of surgery and the risk of bleeding.

• acebutolol

  acebutolol and aspirin both increase serum potassium. Use Caution/Monitor.
  
  aspirin decreases effects of acebutolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.

• aceclofenac

  aceclofenac and aspirin both increase anticoagulation. Use Caution/Monitor.
  
  aceclofenac and aspirin both increase serum potassium. Use Caution/Monitor.

• acemetacin

  acemetacin and aspirin both increase anticoagulation. Use Caution/Monitor.
  
  acemetacin and aspirin both increase serum potassium. Use Caution/Monitor.

• acetazolamide

  acetazolamide, aspirin. Either increases levels of the other by Other (see comment). Use Caution/Monitor. Comment: Carbonic anhydrase inhibitors (CAIs) and salicylates inhibit each other's renal tubular secretion, resulting in increased plasma levels. CAIs also shift salicylates from plasma to the CNS, leading to potential neurotoxicity.
  
  acetazolamide, aspirin. Mechanism: passive renal tubular reabsorption due to increased pH. Use Caution/Monitor. Salicylate levels increased at moderate doses; risk of CNS toxicity. Salicylate levels decreased at large doses (d/t increased renal excretion of unchanged salicylic acid).

• acrivastine

  acrivastine and carisoprodol both increase sedation. Use Caution/Monitor.

• agrimony

  aspirin and agrimony both increase anticoagulation. Use Caution/Monitor.

• albuterol

  codeine increases and albuterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  aspirin increases and albuterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• alfalfa

  aspirin and alfalfa both increase anticoagulation. Use Caution/Monitor.

• alfentanil

  carisoprodol and alfentanil both increase sedation. Use Caution/Monitor.
  
  alfentanil and codeine both increase sedation. Use Caution/Monitor.

• alfuzosin

  aspirin decreases effects of alfuzosin by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.

• aliskiren

  aspirin will decrease the level or effect of aliskiren by Other (see comment). Use Caution/Monitor. In patients who are elderly, volume-depleted (including those on diuretic therapy), or with compromised renal function, coadministration of NSAIDs with drugs that affect RAAS may increase the risk of renal impairment (including acute renal failure) and cause loss of antihypertensive effect. Monitor renal function periodically.

• alprazolam

  alprazolam and codeine both increase sedation. Use Caution/Monitor.
  
  alprazolam and carisoprodol both increase sedation. Use Caution/Monitor.

• alteplase

  aspirin, alteplase. Either increases toxicity of the other by anticoagulation. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; monitor closely.

• American ginseng

  aspirin and American ginseng both increase anticoagulation. Use Caution/Monitor.

• amiloride

  amiloride and aspirin both increase serum potassium. Modify Therapy/Monitor Closely.

• amiodarone

  amiodarone will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• amisulpride

  amisulpride and carisoprodol both increase sedation. Use Caution/Monitor.

• amitriptyline

  carisoprodol and amitriptyline both increase sedation. Use Caution/Monitor.
  
  codeine and amitriptyline both increase sedation. Use Caution/Monitor.

• amobarbital

  amobarbital and codeine both increase sedation. Use Caution/Monitor.
  
  amobarbital and carisoprodol both increase sedation. Use Caution/Monitor.

• amoxapine

  codeine and amoxapine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and amoxapine both increase sedation. Use Caution/Monitor.

• amoxicillin

  amoxicillin, aspirin. Either increases levels of the other by plasma protein binding competition. Use Caution/Monitor.
  
  amoxicillin, aspirin. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor.

• ampicillin

  ampicillin, aspirin. Either increases levels of the other by plasma protein binding competition. Use Caution/Monitor.

• anagrelide

  aspirin, anagrelide. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; increases risk of bleeding; monitor closely.
  
  anagrelide, aspirin. Either increases toxicity of the other by Mechanism: pharmacodynamic synergism. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; increases risk of bleeding; monitor closely.

• antithrombin alfa

  antithrombin alfa and aspirin both increase anticoagulation. Modify Therapy/Monitor Closely.
  
  aspirin, antithrombin alfa. Either increases toxicity of the other by anticoagulation. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; monitor closely.

• antithrombin III

  antithrombin III and aspirin both increase anticoagulation. Modify Therapy/Monitor Closely.
  
  aspirin, antithrombin III. Either increases toxicity of the other by anticoagulation. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; monitor closely.

• apixaban

  aspirin and apixaban both increase anticoagulation. Modify Therapy/Monitor Closely. Both drugs have the potential to cause bleeding. The need for simultaneous use of low-dose aspirin (<100 mg/day) with anticoagulants are common for patients with cardiovascular disease, but may result in increased bleeding; monitor closely. Promptly evaluate any signs or symptoms of blood loss if treated concomitantly with low-dose aspiriin. Avoid coadministration with chronic use of higher dose aspirin. In 1 trial (APPRAISE-2), therapy was terminated because of significantly increased bleeding when apixaban was administered with dual antiplatelet therapy (eg, aspirin plus clopidogrel) compared with single antiplatelet treatment

• apomorphine

  codeine and apomorphine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and apomorphine both increase sedation. Use Caution/Monitor.

• arformoterol

  codeine increases and arformoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  aspirin increases and arformoterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• argatroban

  argatroban and aspirin both increase anticoagulation. Modify Therapy/Monitor Closely.
  
  aspirin, argatroban. Either increases toxicity of the other by anticoagulation. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; monitor closely.

• aripiprazole

  codeine and aripiprazole both increase sedation. Use Caution/Monitor.
  
  carisoprodol and aripiprazole both increase sedation. Use Caution/Monitor.

• armodafinil

  codeine increases and armodafinil decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• asenapine

  aspirin decreases effects of asenapine by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.

• artemether/lumefantrine

  artemether/lumefantrine will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

• asenapine

  asenapine and carisoprodol both increase sedation. Use Caution/Monitor.

• asenapine transdermal

  asenapine transdermal and carisoprodol both increase sedation. Use Caution/Monitor.

• atenolol

  atenolol and aspirin both increase serum potassium. Use Caution/Monitor.
  
  aspirin decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.

• avapritinib

  avapritinib and carisoprodol both increase sedation. Use Caution/Monitor.

• azelastine

  azelastine and carisoprodol both increase sedation. Use Caution/Monitor.
  
  azelastine and codeine both increase sedation. Use Caution/Monitor.

• azficel-T

  azficel-T, aspirin. Other (see comment). Use Caution/Monitor. Comment: Patients taking aspirin may experience increased bruising or bleeding at biopsy and/or injection sites. Concomitant use of aspirin is not recommended. .

• azilsartan

  aspirin, azilsartan. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  aspirin decreases effects of azilsartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.

• baclofen

  baclofen and carisoprodol both increase sedation. Use Caution/Monitor.
  
  baclofen and codeine both increase sedation. Use Caution/Monitor.

• belladonna and opium

  codeine and belladonna and opium both increase sedation. Use Caution/Monitor.
  
  carisoprodol and belladonna and opium both increase sedation. Use Caution/Monitor.

• bemiparin

  bemiparin and aspirin both increase anticoagulation. Modify Therapy/Monitor Closely.

• benazepril

  benazepril, aspirin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly with high dose aspirin, in elderly or volume depleted individuals.

• bendroflumethiazide

  aspirin increases and bendroflumethiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• benperidol

  codeine and benperidol both increase sedation. Use Caution/Monitor.
  
  carisoprodol and benperidol both increase sedation. Use Caution/Monitor.

• benzphetamine

  codeine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  carisoprodol increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• betaxolol

  betaxolol and aspirin both increase serum potassium. Use Caution/Monitor.
  
  aspirin decreases effects of betaxolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.

• betrixaban

  aspirin, betrixaban. Either increases levels of the other by anticoagulation. Use Caution/Monitor.

• bimatoprost

  bimatoprost, aspirin. unspecified interaction mechanism. Use Caution/Monitor. There are conflicting reports from studies of either increased or decreased IOP when ophthalmic prostaglandins are coadministered with NSAIDs (either systemic or ophthalmic).

• bisoprolol

  bisoprolol and aspirin both increase serum potassium. Use Caution/Monitor.
  
  aspirin decreases effects of bisoprolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.

• bivalirudin

  bivalirudin and aspirin both increase anticoagulation. Modify Therapy/Monitor Closely.
  
  aspirin, bivalirudin. Either increases toxicity of the other by anticoagulation. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; monitor closely.

• brexanolone

  brexanolone, carisoprodol. Either increases toxicity of the other by sedation. Use Caution/Monitor.
  
  brexanolone, codeine. Either increases toxicity of the other by sedation. Use Caution/Monitor.

• brexpiprazole

  brexpiprazole and carisoprodol both increase sedation. Use Caution/Monitor.
  
  brexpiprazole and codeine both increase sedation. Use Caution/Monitor.

• brimonidine

  brimonidine and carisoprodol both increase sedation. Use Caution/Monitor.

• brinzolamide

  brinzolamide, aspirin. Either increases levels of the other by Other (see comment). Use Caution/Monitor. Comment: Carbonic anhydrase inhibitors (CAIs) and salicylates inhibit each other's renal tubular secretion, resulting in increased plasma levels. CAIs also shift salicylates from plasma to the CNS, leading to potential neurotoxicity.

• brivaracetam

  brivaracetam and codeine both increase sedation. Use Caution/Monitor.

• brivaracetam

  brivaracetam and carisoprodol both increase sedation. Use Caution/Monitor.

• brompheniramine

  brompheniramine and carisoprodol both increase sedation. Use Caution/Monitor.
  
  brompheniramine and codeine both increase sedation. Use Caution/Monitor.

• bumetanide

  aspirin increases and bumetanide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  aspirin decreases effects of bumetanide by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.

• buprenorphine

  buprenorphine and codeine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and buprenorphine both increase sedation. Use Caution/Monitor.

• buprenorphine buccal

  carisoprodol and buprenorphine buccal both increase sedation. Use Caution/Monitor.
  
  buprenorphine buccal and codeine both increase sedation. Use Caution/Monitor.

• buprenorphine, long-acting injection

  buprenorphine, long-acting injection increases effects of carisoprodol by Other (see comment). Modify Therapy/Monitor Closely. Comment: Buprenorphine may enhance the neuromuscular blocking action of skeletal muscle relaxants and increase risk for respiratory depression. Monitor for signs of respiratory depression that may be greater than otherwise expected and decrease muscle relaxant dosage as necessary.
  
  codeine increases toxicity of buprenorphine, long-acting injection by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of buprenorphine and benzodiazepines or other CNS depressants increases risk of adverse reactions including overdose, respiratory depression, and death. Cessation of benzodiazepines or other CNS depressants is preferred in most cases. In some cases, monitoring at a higher level of care for tapering CNS depressants may be appropriate. In others, gradually tapering a patient off of a prescribed benzodiazepine or other CNS depressant or decreasing to the lowest effective dose may be appropriate.

• bupropion

  bupropion will decrease the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents the conversion of codeine to its active metabolite morphine.

• butabarbital

  butabarbital and carisoprodol both increase sedation. Use Caution/Monitor.

• butabarbital

  butabarbital and codeine both increase sedation. Use Caution/Monitor.

• butalbital

  butalbital and codeine both increase sedation. Use Caution/Monitor.
  
  butalbital and carisoprodol both increase sedation. Use Caution/Monitor.

• butorphanol

  butorphanol and codeine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and butorphanol both increase sedation. Use Caution/Monitor.

• caffeine

  codeine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• candesartan

  candesartan and aspirin both increase serum potassium. Use Caution/Monitor.
  
  aspirin decreases effects of candesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  candesartan, aspirin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.

• cannabidiol

  cannabidiol will increase the level or effect of carisoprodol by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Consider reducing the dose of sensitive CYP2C19 substrates, as clinically appropriate, when coadministered with cannabidiol.

• captopril

  captopril, aspirin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly with high dose aspirin, elderly or volume depleted individuals.

• carbenoxolone

  aspirin increases and carbenoxolone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• carbinoxamine

  carbinoxamine and codeine both increase sedation. Use Caution/Monitor.
  
  carbinoxamine and carisoprodol both increase sedation. Use Caution/Monitor.

• carisoprodol

  carisoprodol and codeine both increase sedation. Use Caution/Monitor.

• carvedilol

  carvedilol and aspirin both increase serum potassium. Use Caution/Monitor.
  
  aspirin decreases effects of carvedilol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.

• celecoxib

  aspirin and celecoxib both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and celecoxib both increase serum potassium. Use Caution/Monitor.

• celiprolol

  celiprolol and aspirin both increase serum potassium. Use Caution/Monitor.
  
  aspirin decreases effects of celiprolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.

• cenobamate

  cenobamate will increase the level or effect of carisoprodol by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Consider a dose reduction of CYP2C19 substrates, as clinically appropriate, when used concomitantly with cenobamate.
  
  cenobamate, carisoprodol. Either increases effects of the other by sedation. Use Caution/Monitor.

• celecoxib

  celecoxib decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• cenobamate

  cenobamate, codeine. Either increases effects of the other by sedation. Use Caution/Monitor.

• chloral hydrate

  chloral hydrate and codeine both increase sedation. Use Caution/Monitor.
  
  chloral hydrate and carisoprodol both increase sedation. Use Caution/Monitor.

• chlordiazepoxide

  chlordiazepoxide and codeine both increase sedation. Use Caution/Monitor.
  
  chlordiazepoxide and carisoprodol both increase sedation. Use Caution/Monitor.

• chloroquine

  chloroquine will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• chlorothiazide

  aspirin increases and chlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• chlorpheniramine

  chlorpheniramine and carisoprodol both increase sedation. Use Caution/Monitor.

• chlorpheniramine

  chlorpheniramine and codeine both increase sedation. Use Caution/Monitor.

• chlorpromazine

  chlorpromazine will decrease the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine
  
  codeine and chlorpromazine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and chlorpromazine both increase sedation. Use Caution/Monitor.

• chlorpropamide

  aspirin increases effects of chlorpropamide by unknown mechanism. Use Caution/Monitor. Risk of hypoglycemia.

• chlorthalidone

  aspirin increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• chlorzoxazone

  chlorzoxazone and codeine both increase sedation. Use Caution/Monitor.

• choline magnesium trisalicylate

  aspirin and choline magnesium trisalicylate both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and choline magnesium trisalicylate both increase serum potassium. Use Caution/Monitor.

• cilostazol

  aspirin, cilostazol. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; monitor closely.

• cinnamon

  aspirin and cinnamon both increase anticoagulation. Use Caution/Monitor.

• cinnarizine

  cinnarizine and carisoprodol both increase sedation. Use Caution/Monitor.

• cimetidine

  cimetidine will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• cinacalcet

  cinacalcet decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• cinnarizine

  cinnarizine and codeine both increase sedation. Use Caution/Monitor.

• ciprofloxacin

  aspirin decreases levels of ciprofloxacin by Other (see comment). Use Caution/Monitor. Comment: Buffered aspirin may decrease absorption of quinolones. Consider administering 2 hr before or 6 hr after, buffered aspirin administration.

• citalopram

  citalopram, aspirin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. If possible, avoid concurrent use.

• clemastine

  clemastine and carisoprodol both increase sedation. Use Caution/Monitor.
  
  clemastine and codeine both increase sedation. Use Caution/Monitor.

• clobazam

  carisoprodol, clobazam. Other (see comment). Use Caution/Monitor. Comment: Concomitant administration can increase the potential for CNS effects (e.g., increased sedation or respiratory depression).
  
  codeine, clobazam. Other (see comment). Use Caution/Monitor. Comment: Concomitant administration can increase the potential for CNS effects (e.g., increased sedation or respiratory depression).
  
  clobazam decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• clomipramine

  clomipramine, aspirin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. Clomipramine inhib. serotonin uptake by platelets.
  
  codeine and clomipramine both increase sedation. Use Caution/Monitor.
  
  clomipramine decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.
  
  carisoprodol and clomipramine both increase sedation. Use Caution/Monitor.

• clonazepam

  clonazepam and carisoprodol both increase sedation. Use Caution/Monitor.
  
  clonazepam and codeine both increase sedation. Use Caution/Monitor.

• clopidogrel

  aspirin, clopidogrel. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; monitor closely.

• clorazepate

  clorazepate and codeine both increase sedation. Use Caution/Monitor.
  
  clorazepate and carisoprodol both increase sedation. Use Caution/Monitor.

• clozapine

  codeine and clozapine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and clozapine both increase sedation. Use Caution/Monitor.
  
  clozapine decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• cocaine topical

  cocaine topical decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• codeine

  carisoprodol and codeine both increase sedation. Use Caution/Monitor.

• collagenase clostridium histolyticum

  aspirin increases toxicity of collagenase clostridium histolyticum by anticoagulation. Use Caution/Monitor. Collagenase clostridium histolyticum has high incidence of ecchymosis/contusion at injection site; avoid concomitant anticoagulants (except for low-dose aspirin, ie, up to 150 mg/day).

• cordyceps

  aspirin and cordyceps both increase anticoagulation. Use Caution/Monitor.

• cortisone

  aspirin, cortisone. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of GI ulceration.

• cyclizine

  cyclizine and carisoprodol both increase sedation. Use Caution/Monitor.
  
  cyclizine and codeine both increase sedation. Use Caution/Monitor.

• cyclobenzaprine

  cyclobenzaprine and codeine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and cyclobenzaprine both increase sedation. Use Caution/Monitor.

• cyclopenthiazide

  aspirin increases and cyclopenthiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• cyproheptadine

  cyproheptadine and codeine both increase sedation. Use Caution/Monitor.
  
  cyproheptadine and carisoprodol both increase sedation. Use Caution/Monitor.

• dabigatran

  dabigatran and aspirin both increase anticoagulation. Modify Therapy/Monitor Closely. Both drugs have the potential to cause bleeding. The need for simultaneous use of low-dose aspirin (<100 mg/day) with anticoagulants are common for patients with cardiovascular disease, but may result in increased bleeding; monitor closely. Promptly evaluate any signs or symptoms of blood loss if treated concomitantly with low-dose aspirin. Avoid coadministration with chronic use of higher dose aspirin

• dalteparin

  dalteparin and aspirin both increase anticoagulation. Modify Therapy/Monitor Closely.
  
  aspirin, dalteparin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; monitor closely.

• dantrolene

  dantrolene and codeine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and dantrolene both increase sedation. Use Caution/Monitor.

• daridorexant

  codeine and daridorexant both increase sedation. Modify Therapy/Monitor Closely. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment.
  
  carisoprodol and daridorexant both increase sedation. Modify Therapy/Monitor Closely. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment.

• darifenacin

  darifenacin decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• deferasirox

  deferasirox, aspirin. Other (see comment). Use Caution/Monitor. Comment: Combination may increase GI bleeding, ulceration and irritation. Use with caution.

• defibrotide

  defibrotide increases effects of aspirin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Defibrotide may enhance effects of platelet inhibitors.

• deflazacort

  aspirin, deflazacort. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of GI ulceration.

• desipramine

  carisoprodol and desipramine both increase sedation. Use Caution/Monitor.

• desflurane

  desflurane and codeine both increase sedation. Use Caution/Monitor. Opioids may decrease MAC requirements, less inhalation anesthetic may be required.

• desipramine

  codeine and desipramine both increase sedation. Use Caution/Monitor.
  
  desipramine decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• desirudin

  aspirin, desirudin. Either increases levels of the other by pharmacodynamic synergism. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; monitor closely.

• desvenlafaxine

  desvenlafaxine will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Desvenlafaxine inhibits CYP2D6; with higher desvenlafaxine doses (ie, 400 mg) decrease the CYP2D6 substrate dose by up to 50%; no dosage adjustment needed with desvenlafaxine doses <100 mg

• deutetrabenazine

  codeine and deutetrabenazine both increase sedation. Use Caution/Monitor.

• dexamethasone

  aspirin, dexamethasone. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of GI ulceration.

• dexchlorpheniramine

  dexchlorpheniramine and carisoprodol both increase sedation. Use Caution/Monitor.
  
  dexchlorpheniramine and codeine both increase sedation. Use Caution/Monitor.

• dexfenfluramine

  codeine increases and dexfenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  carisoprodol increases and dexfenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• dexmedetomidine

  dexmedetomidine and carisoprodol both increase sedation. Use Caution/Monitor.
  
  dexmedetomidine and codeine both increase sedation. Use Caution/Monitor.

• dexmethylphenidate

  codeine increases and dexmethylphenidate decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• dextromoramide

  carisoprodol and dextromoramide both increase sedation. Use Caution/Monitor.

• dextroamphetamine

  codeine increases and dextroamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• dextromoramide

  codeine and dextromoramide both increase sedation. Use Caution/Monitor.

• diamorphine

  carisoprodol and diamorphine both increase sedation. Use Caution/Monitor.
  
  codeine and diamorphine both increase sedation. Use Caution/Monitor.

• diazepam

  diazepam and carisoprodol both increase sedation. Use Caution/Monitor.
  
  diazepam and codeine both increase sedation. Use Caution/Monitor.

• diazepam intranasal

  diazepam intranasal, carisoprodol. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration may potentiate the CNS-depressant effects of each drug.

• diclofenac

  aspirin and diclofenac both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and diclofenac both increase serum potassium. Use Caution/Monitor.

• dicloxacillin

  dicloxacillin, aspirin. Either increases levels of the other by plasma protein binding competition. Use Caution/Monitor.

• diethylpropion

  codeine increases and diethylpropion decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• difelikefalin

  difelikefalin and codeine both increase sedation. Use Caution/Monitor.
  
  difelikefalin and carisoprodol both increase sedation. Use Caution/Monitor.

• difenoxin hcl

  carisoprodol and difenoxin hcl both increase sedation. Use Caution/Monitor.
  
  codeine and difenoxin hcl both increase sedation. Use Caution/Monitor.

• diflunisal

  aspirin and diflunisal both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and diflunisal both increase serum potassium. Use Caution/Monitor.

• digoxin

  aspirin and digoxin both increase serum potassium. Use Caution/Monitor.

• dimenhydrinate

  dimenhydrinate and carisoprodol both increase sedation. Use Caution/Monitor.
  
  dimenhydrinate and codeine both increase sedation. Use Caution/Monitor.

• diphenhydramine

  diphenhydramine decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.
  
  diphenhydramine and codeine both increase sedation. Use Caution/Monitor.
  
  diphenhydramine and carisoprodol both increase sedation. Use Caution/Monitor.

• diphenoxylate hcl

  codeine and diphenoxylate hcl both increase sedation. Use Caution/Monitor.
  
  carisoprodol and diphenoxylate hcl both increase sedation. Use Caution/Monitor.

• dipipanone

  codeine and dipipanone both increase sedation. Use Caution/Monitor.
  
  carisoprodol and dipipanone both increase sedation. Use Caution/Monitor.

• dipyridamole

  aspirin, dipyridamole. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; monitor closely.

• dobutamine

  codeine increases and dobutamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  aspirin increases and dobutamine decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• dong quai

  aspirin and dong quai both increase anticoagulation. Use Caution/Monitor.

• dopamine

  codeine increases and dopamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• dopexamine

  carisoprodol increases and dopexamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  codeine increases and dopexamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• dopexamine

  aspirin increases and dopexamine decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• dosulepin

  codeine and dosulepin both increase sedation. Use Caution/Monitor.
  
  carisoprodol and dosulepin both increase sedation. Use Caution/Monitor.

• doxazosin

  aspirin decreases effects of doxazosin by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.

• doxepin

  codeine and doxepin both increase sedation. Use Caution/Monitor.
  
  carisoprodol and doxepin both increase sedation. Use Caution/Monitor.

• doxylamine

  doxylamine and codeine both increase sedation. Use Caution/Monitor.
  
  doxylamine and carisoprodol both increase sedation. Use Caution/Monitor.

• dronedarone

  dronedarone decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• droperidol

  carisoprodol and droperidol both increase sedation. Use Caution/Monitor.

• droperidol

  codeine and droperidol both increase sedation. Use Caution/Monitor.

• drospirenone

  drospirenone and aspirin both increase serum potassium. Modify Therapy/Monitor Closely.

• duloxetine

  duloxetine, aspirin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.
  
  duloxetine decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• edoxaban

  edoxaban, aspirin. Either increases toxicity of the other by anticoagulation. Modify Therapy/Monitor Closely. Both drugs have the potential to cause bleeding. The need for simultaneous use of low-dose aspirin (<100 mg/day) with anticoagulants are common for patients with cardiovascular disease, but may result in increased bleeding; monitor closely. Promptly evaluate any signs or symptoms of blood loss if treated concomitantly with low-dose aspirin. Avoid coadministration with chronic use of higher dose aspirin.

• elagolix

  elagolix will increase the level or effect of carisoprodol by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Elagolix is a weak CYP2C19 inhibitor. Caution with sensitive CYP2C19 substrates.

• elvitegravir/cobicistat/emtricitabine/tenofovir DF

  elvitegravir/cobicistat/emtricitabine/tenofovir DF, aspirin. Either increases toxicity of the other by decreasing renal clearance. Modify Therapy/Monitor Closely. Toxicity may result from coadministration of emtricitabine and tenofovir with other drugs that are also primarily excreted by glomerular filtration and/or active tubular secretion including high-dose or multiple-dose NSAIDs; alternatives to NSAIDs should be considered.
  
  elvitegravir/cobicistat/emtricitabine/tenofovir DF increases levels of codeine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Cobicistat is a CYP2D6 inhibitor; caution with CYP2D6 substrates for which elevated plasma concentrations are associated with serious and/or life-threatening events.

• enalapril

  enalapril, aspirin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly with high dose aspirin, in elderly or volume depleted individuals.

• ephedrine

  codeine increases and ephedrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• enoxaparin

  enoxaparin and aspirin both increase anticoagulation. Use Caution/Monitor. Additive effects are intended when both drugs are prescribed as indicated for unstable angina, non-Q-wave MI, and STEMI
  
  aspirin, enoxaparin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; monitor closely.

• ephedrine

  aspirin increases and ephedrine decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• epinephrine

  aspirin increases and epinephrine decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  codeine increases and epinephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• epinephrine racemic

  codeine increases and epinephrine racemic decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  aspirin increases and epinephrine racemic decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• epoprostenol

  aspirin and epoprostenol both increase anticoagulation. Use Caution/Monitor.

• esketamine intranasal

  esketamine intranasal, codeine. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely.
  
  esketamine intranasal, carisoprodol. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely.

• eprosartan

  eprosartan and aspirin both increase serum potassium. Use Caution/Monitor.
  
  aspirin decreases effects of eprosartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  eprosartan, aspirin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.

• eptifibatide

  aspirin, eptifibatide. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; monitor closely.

• escitalopram

  escitalopram, aspirin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• eslicarbazepine acetate

  eslicarbazepine acetate will increase the level or effect of carisoprodol by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.

• esmolol

  esmolol and aspirin both increase serum potassium. Use Caution/Monitor.
  
  aspirin decreases effects of esmolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.

• estazolam

  estazolam and codeine both increase sedation. Use Caution/Monitor.

• estazolam

  estazolam and carisoprodol both increase sedation. Use Caution/Monitor.

• ethacrynic acid

  aspirin increases and ethacrynic acid decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• ethanol

  carisoprodol and ethanol both increase sedation. Use Caution/Monitor.
  
  codeine and ethanol both increase sedation. Use Caution/Monitor.

• etodolac

  aspirin and etodolac both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and etodolac both increase serum potassium. Use Caution/Monitor.

• etomidate

  etomidate and codeine both increase sedation. Use Caution/Monitor.
  
  etomidate and carisoprodol both increase sedation. Use Caution/Monitor.

• fedratinib

  fedratinib will increase the level or effect of carisoprodol by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP2C19 substrates as necessary.
  
  fedratinib will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP2D6 substrates as necessary.

• fenbufen

  aspirin and fenbufen both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and fenbufen both increase serum potassium. Use Caution/Monitor.

• fenfluramine

  carisoprodol increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  codeine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• fennel

  aspirin and fennel both increase anticoagulation. Use Caution/Monitor.

• fenoprofen

  aspirin and fenoprofen both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and fenoprofen both increase serum potassium. Use Caution/Monitor.

• feverfew

  aspirin and feverfew both increase anticoagulation. Use Caution/Monitor.

• fexinidazole

  fexinidazole will increase the level or effect of carisoprodol by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.

• fish oil

  fish oil, aspirin. Other (see comment). Use Caution/Monitor. Comment: Patients taking fish oil and an anticoagulant or other drug affecting coagulation should be monitored periodically due to potential increased risk of bleeding. .

• fish oil triglycerides

  fish oil triglycerides will increase the level or effect of aspirin by anticoagulation. Use Caution/Monitor. Prolonged bleeding reported in patients taking antiplatelet agents or anticoagulants and oral omega-3 fatty acids. Periodically monitor bleeding time in patients receiving fish oil triglycerides and concomitant antiplatelet agents or anticoagulants.

• flibanserin

  codeine and flibanserin both increase sedation. Modify Therapy/Monitor Closely. Risk for sedation increased if flibanserin is coadministration with other CNS depressants.

• fludrocortisone

  aspirin, fludrocortisone. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of GI ulceration.

• fluoxetine

  fluoxetine, aspirin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.
  
  fluoxetine will decrease the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine

• fluphenazine

  carisoprodol and fluphenazine both increase sedation. Use Caution/Monitor.
  
  codeine and fluphenazine both increase sedation. Use Caution/Monitor.

• flurbiprofen

  aspirin and flurbiprofen both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and flurbiprofen both increase serum potassium. Use Caution/Monitor.

• flurazepam

  flurazepam and codeine both increase sedation. Use Caution/Monitor.
  
  flurazepam and carisoprodol both increase sedation. Use Caution/Monitor.

• fluvoxamine

  fluvoxamine, aspirin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding SSRIs inhib. serotonin uptake by platelets.

• fondaparinux

  fondaparinux and aspirin both increase anticoagulation. Modify Therapy/Monitor Closely.

• formoterol

  codeine increases and formoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  aspirin increases and formoterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• forskolin

  aspirin and forskolin both increase anticoagulation. Use Caution/Monitor.

• gabapentin

  gabapentin, codeine. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of CNS depressants can result in serious, life-threatening, and fatal respiratory depression. Use lowest dose possible and monitor for respiratory depression and sedation.

• gabapentin enacarbil

  gabapentin enacarbil, codeine. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of CNS depressants can result in serious, life-threatening, and fatal respiratory depression. Use lowest dose possible and monitor for respiratory depression and sedation.

• ganaxolone

  codeine and ganaxolone both increase sedation. Use Caution/Monitor.
  
  carisoprodol and ganaxolone both increase sedation. Use Caution/Monitor.

• fosinopril

  fosinopril, aspirin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly with high dose aspirin, in elderly or volume depleted individuals.

• haloperidol

  codeine and haloperidol both increase sedation. Use Caution/Monitor.
  
  carisoprodol and haloperidol both increase sedation. Use Caution/Monitor.
  
  haloperidol decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• furosemide

  aspirin increases and furosemide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• garlic

  aspirin and garlic both increase anticoagulation. Use Caution/Monitor.

• gentamicin

  aspirin increases and gentamicin decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• ginger

  aspirin and ginger both increase anticoagulation. Use Caution/Monitor.

• ginkgo biloba

  aspirin and ginkgo biloba both increase anticoagulation. Use Caution/Monitor.

• glimepiride

  aspirin increases effects of glimepiride by unknown mechanism. Use Caution/Monitor. Risk of hypoglycemia.

• glipizide

  aspirin increases effects of glipizide by unknown mechanism. Use Caution/Monitor. Risk of hypoglycemia.

• glyburide

  aspirin increases effects of glyburide by unknown mechanism. Use Caution/Monitor. Risk of hypoglycemia.

• green tea

  green tea increases effects of aspirin by pharmacodynamic synergism. Use Caution/Monitor. (Theoretical, due to caffeine content). Combination may increase risk of bleeding.

• griseofulvin

  griseofulvin decreases levels of aspirin by unknown mechanism. Use Caution/Monitor.

• heparin

  heparin and aspirin both increase anticoagulation. Modify Therapy/Monitor Closely.
  
  aspirin, heparin. Either increases toxicity of the other by anticoagulation. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; monitor closely.

• horse chestnut seed

  aspirin and horse chestnut seed both increase anticoagulation. Use Caution/Monitor.

• hyaluronidase

  aspirin decreases effects of hyaluronidase by Other (see comment). Use Caution/Monitor. Comment: Salicylates, when given in large systemic doses, may render tissues partially resistant to the action of hyaluronidase. Patients may require larger amounts of hyaluronidase for equivalent dispersing effect.

• hydralazine

  aspirin decreases effects of hydralazine by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.

• hydrochlorothiazide

  aspirin increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• hydrocortisone

  aspirin, hydrocortisone. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of GI ulceration.

• hydromorphone

  carisoprodol and hydromorphone both increase sedation. Use Caution/Monitor.
  
  codeine and hydromorphone both increase sedation. Use Caution/Monitor.

• hydroxyzine

  hydroxyzine and codeine both increase sedation. Use Caution/Monitor.
  
  hydroxyzine and carisoprodol both increase sedation. Use Caution/Monitor.

• ibrutinib

  ibrutinib will increase the level or effect of aspirin by anticoagulation. Use Caution/Monitor. Ibrutinib may increase the risk of hemorrhage in patients receiving antiplatelet or anticoagulant therapies and monitor for signs of bleeding.

• ibuprofen

  aspirin and ibuprofen both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and ibuprofen both increase serum potassium. Use Caution/Monitor.

• ibuprofen IV

  aspirin will increase the level or effect of ibuprofen IV by acidic (anionic) drug competition for renal tubular clearance. Modify Therapy/Monitor Closely.
  
  aspirin and ibuprofen IV both increase anticoagulation. Modify Therapy/Monitor Closely.
  
  aspirin and ibuprofen IV both increase serum potassium. Use Caution/Monitor.

• icosapent

  icosapent, aspirin. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Icosapent may prolong bleeding time; monitor periodically if coadministered with other drugs that affect bleeding.

• iloperidone

  codeine and iloperidone both increase sedation. Use Caution/Monitor.
  
  carisoprodol and iloperidone both increase sedation. Use Caution/Monitor.

• imatinib

  imatinib, aspirin. Either increases toxicity of the other by Other (see comment). Modify Therapy/Monitor Closely. Comment: Imatinib may cause thrombocytopenia; bleeding risk increased when imatinib is coadministered with anticoagulants, NSAIDs, platelet inhibitors, and thrombolytic agents.

• imipramine

  codeine and imipramine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and imipramine both increase sedation. Use Caution/Monitor.
  
  imipramine decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• incobotulinumtoxinA

  carisoprodol, incobotulinumtoxinA. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Muscle relaxants may enhance botulinum toxin effects. Closely monitor for increased neuromuscular blockade.

• indapamide

  aspirin increases and indapamide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• indomethacin

  aspirin and indomethacin both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and indomethacin both increase serum potassium. Use Caution/Monitor.

• insulin aspart

  aspirin increases effects of insulin aspart by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of insulin with high doses of salicylates (3 g/day or more) may increase risk for hypoglycemia. Insulin dose adjustment and increased frequency of glucose monitoring may be required.

• insulin aspart protamine/insulin aspart

  aspirin increases effects of insulin aspart protamine/insulin aspart by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of insulin with high doses of salicylates (3 g/day or more) may increase risk for hypoglycemia. Insulin dose adjustment and increased frequency of glucose monitoring may be required.

• insulin degludec

  aspirin increases effects of insulin degludec by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of insulin with high doses of salicylates (3 g/day or more) may increase risk for hypoglycemia. Insulin dose adjustment and increased frequency of glucose monitoring may be required.

• insulin degludec/insulin aspart

  aspirin, insulin degludec/insulin aspart. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs decrease blood glucose.

• insulin detemir

  aspirin increases effects of insulin detemir by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of insulin with high doses of salicylates (3 g/day or more) may increase risk for hypoglycemia. Insulin dose adjustment and increased frequency of glucose monitoring may be required.

• insulin glargine

  aspirin increases effects of insulin glargine by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of insulin with high doses of salicylates (3 g/day or more) may increase risk for hypoglycemia. Insulin dose adjustment and increased frequency of glucose monitoring may be required.

• insulin glulisine

  aspirin increases effects of insulin glulisine by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of insulin with high doses of salicylates (3 g/day or more) may increase risk for hypoglycemia. Insulin dose adjustment and increased frequency of glucose monitoring may be required.

• insulin inhaled

  aspirin increases effects of insulin inhaled by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of insulin with high doses of salicylates (3 g/day or more) may increase risk for hypoglycemia. Insulin dose adjustment and increased frequency of glucose monitoring may be required.

• insulin isophane human/insulin regular human

  aspirin increases effects of insulin isophane human/insulin regular human by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of insulin with high doses of salicylates (3 g/day or more) may increase risk for hypoglycemia. Insulin dose adjustment and increased frequency of glucose monitoring may be required.

• insulin lispro

  aspirin increases effects of insulin lispro by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of insulin with high doses of salicylates (3 g/day or more) may increase risk for hypoglycemia. Insulin dose adjustment and increased frequency of glucose monitoring may be required.

• insulin lispro protamine/insulin lispro

  aspirin increases effects of insulin lispro protamine/insulin lispro by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of insulin with high doses of salicylates (3 g/day or more) may increase risk for hypoglycemia. Insulin dose adjustment and increased frequency of glucose monitoring may be required.

• insulin NPH

  aspirin increases effects of insulin NPH by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of insulin with high doses of salicylates (3 g/day or more) may increase risk for hypoglycemia. Insulin dose adjustment and increased frequency of glucose monitoring may be required.

• insulin regular human

  aspirin increases effects of insulin regular human by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of insulin with high doses of salicylates (3 g/day or more) may increase risk for hypoglycemia. Insulin dose adjustment and increased frequency of glucose monitoring may be required.

• irbesartan

  irbesartan and aspirin both increase serum potassium. Use Caution/Monitor.
  
  aspirin decreases effects of irbesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  irbesartan, aspirin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.

• isoniazid

  isoniazid decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• isoproterenol

  codeine increases and isoproterenol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  aspirin increases and isoproterenol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• ketamine

  ketamine and codeine both increase sedation. Use Caution/Monitor.
  
  ketamine and carisoprodol both increase sedation. Use Caution/Monitor.

• ketoprofen

  aspirin and ketoprofen both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and ketoprofen both increase serum potassium. Use Caution/Monitor.

• ketoconazole

  ketoconazole decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• ketorolac

  aspirin and ketorolac both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and ketorolac both increase serum potassium. Use Caution/Monitor.

• ketorolac intranasal

  aspirin and ketorolac intranasal both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and ketorolac intranasal both increase serum potassium. Use Caution/Monitor.

• ketotifen, ophthalmic

  carisoprodol and ketotifen, ophthalmic both increase sedation. Use Caution/Monitor.

• ketotifen, ophthalmic

  codeine and ketotifen, ophthalmic both increase sedation. Use Caution/Monitor.

• labetalol

  labetalol and aspirin both increase serum potassium. Use Caution/Monitor.
  
  aspirin decreases effects of labetalol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.

• lasmiditan

  lasmiditan, codeine. Either increases effects of the other by sedation. Use Caution/Monitor. Coadministration of lasmiditan and other CNS depressant drugs, including alcohol have not been evaluated in clinical studies. Lasmiditan may cause sedation, as well as other cognitive and/or neuropsychiatric adverse reactions.
  
  lasmiditan, carisoprodol. Either increases effects of the other by sedation. Use Caution/Monitor. Coadministration of lasmiditan and other CNS depressant drugs, including alcohol have not been evaluated in clinical studies. Lasmiditan may cause sedation, as well as other cognitive and/or neuropsychiatric adverse reactions.

• latanoprost

  latanoprost, aspirin. unspecified interaction mechanism. Use Caution/Monitor. There are conflicting reports from studies of either increased or decreased IOP when ophthalmic prostaglandins are coadministered with NSAIDs (either systemic or ophthalmic).

• latanoprostene bunod ophthalmic

  latanoprostene bunod ophthalmic, aspirin. unspecified interaction mechanism. Use Caution/Monitor. There are conflicting reports from studies of either increased or decreased IOP when ophthalmic prostaglandins are coadministered with NSAIDs (either systemic or ophthalmic).

• lemborexant

  lemborexant, codeine. Either increases effects of the other by sedation. Modify Therapy/Monitor Closely. Dosage adjustment may be necessary if lemborexant is coadministered with other CNS depressants because of potentially additive effects.
  
  lemborexant, carisoprodol. Either increases effects of the other by sedation. Modify Therapy/Monitor Closely. Dosage adjustment may be necessary if lemborexant is coadministered with other CNS depressants because of potentially additive effects.

• letermovir

  letermovir increases levels of codeine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• levalbuterol

  aspirin increases and levalbuterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• levomilnacipran

  levomilnacipran, aspirin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. SNRIs may further impair platelet activity in patients taking antiplatelet or anticoagulant drugs.

• levorphanol

  carisoprodol and levorphanol both increase sedation. Use Caution/Monitor.

• levalbuterol

  codeine increases and levalbuterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• levoketoconazole

  levoketoconazole decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• levorphanol

  codeine and levorphanol both increase sedation. Use Caution/Monitor.

• lisdexamfetamine

  codeine increases and lisdexamfetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• lisinopril

  lisinopril, aspirin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly with high dose aspirin, in elderly or volume depleted individuals.

• lithium

  aspirin increases levels of lithium by decreasing renal clearance. Use Caution/Monitor.

• lofepramine

  carisoprodol and lofepramine both increase sedation. Use Caution/Monitor.
  
  codeine and lofepramine both increase sedation. Use Caution/Monitor.

• lofexidine

  codeine and lofexidine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and lofexidine both increase sedation. Use Caution/Monitor.

• lopinavir

  lopinavir decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• loprazolam

  loprazolam and carisoprodol both increase sedation. Use Caution/Monitor.

• loprazolam

  loprazolam and codeine both increase sedation. Use Caution/Monitor.

• lorazepam

  lorazepam and carisoprodol both increase sedation. Use Caution/Monitor.
  
  lorazepam and codeine both increase sedation. Use Caution/Monitor.

• lorcaserin

  lorcaserin will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• lormetazepam

  lormetazepam and carisoprodol both increase sedation. Use Caution/Monitor.

• lormetazepam

  lormetazepam and codeine both increase sedation. Use Caution/Monitor.

• lornoxicam

  aspirin and lornoxicam both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and lornoxicam both increase serum potassium. Use Caution/Monitor.

• losartan

  losartan and aspirin both increase serum potassium. Use Caution/Monitor.
  
  aspirin decreases effects of losartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  losartan, aspirin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.

• loxapine

  codeine and loxapine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and loxapine both increase sedation. Use Caution/Monitor.

• loxapine inhaled

  codeine and loxapine inhaled both increase sedation. Use Caution/Monitor.
  
  carisoprodol and loxapine inhaled both increase sedation. Use Caution/Monitor.

• lumacaftor/ivacaftor

  lumacaftor/ivacaftor, carisoprodol. affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. In vitro studies suggest that lumacaftor may induce and ivacaftor may inhibit CYP2C19 substrates. .

• lumefantrine

  lumefantrine will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

• lurasidone

  lurasidone, carisoprodol. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Potential for increased CNS depressant effects when used concurrently; monitor for increased adverse effects and toxicity.
  
  lurasidone, codeine. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Potential for increased CNS depressant effects when used concurrently; monitor for increased adverse effects and toxicity.

• maprotiline

  carisoprodol and maprotiline both increase sedation. Use Caution/Monitor.
  
  codeine and maprotiline both increase sedation. Use Caution/Monitor.

• marijuana

  carisoprodol and marijuana both increase sedation. Use Caution/Monitor.
  
  codeine and marijuana both increase sedation. Use Caution/Monitor.

• meclofenamate

  aspirin and meclofenamate both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and meclofenamate both increase serum potassium. Use Caution/Monitor.

• mefenamic acid

  aspirin and mefenamic acid both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and mefenamic acid both increase serum potassium. Use Caution/Monitor.

• melatonin

  melatonin increases effects of aspirin by anticoagulation. Use Caution/Monitor. Melatonin may decrease prothrombin time.
  
  carisoprodol and melatonin both increase sedation. Use Caution/Monitor.
  
  codeine and melatonin both increase sedation. Use Caution/Monitor.

• meloxicam

  aspirin and meloxicam both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and meloxicam both increase serum potassium. Use Caution/Monitor.

• meperidine

  codeine and meperidine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and meperidine both increase sedation. Use Caution/Monitor.

• meprobamate

  codeine and meprobamate both increase sedation. Use Caution/Monitor.
  
  carisoprodol and meprobamate both increase sedation. Use Caution/Monitor.

• mesalamine

  mesalamine, aspirin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Additive nephrotoxicity.

• metaproterenol

  aspirin increases and metaproterenol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  codeine increases and metaproterenol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• metaxalone

  carisoprodol and metaxalone both increase sedation. Use Caution/Monitor.

• methazolamide

  methazolamide, aspirin. Either increases levels of the other by Other (see comment). Use Caution/Monitor. Comment: Carbonic anhydrase inhibitors (CAIs) and salicylates inhibit each other's renal tubular secretion, resulting in increased plasma levels. CAIs also shift salicylates from plasma to the CNS, leading to potential neurotoxicity.

• metaxalone

  metaxalone and codeine both increase sedation. Use Caution/Monitor.

• methadone

  codeine and methadone both increase sedation. Use Caution/Monitor.
  
  carisoprodol and methadone both increase sedation. Use Caution/Monitor.

• methamphetamine

  codeine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• methocarbamol

  carisoprodol and methocarbamol both increase sedation. Use Caution/Monitor.

• methocarbamol

  methocarbamol and codeine both increase sedation. Use Caution/Monitor.

• methyclothiazide

  aspirin increases and methyclothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor. .

• methylenedioxymethamphetamine

  codeine increases and methylenedioxymethamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  carisoprodol increases and methylenedioxymethamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• methylprednisolone

  aspirin, methylprednisolone. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of GI ulceration.

• metolazone

  aspirin increases and metolazone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• metoprolol

  metoprolol and aspirin both increase serum potassium. Use Caution/Monitor.
  
  aspirin decreases effects of metoprolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.

• midazolam

  midazolam and carisoprodol both increase sedation. Use Caution/Monitor.
  
  midazolam and codeine both increase sedation. Use Caution/Monitor.

• midazolam intranasal

  midazolam intranasal, codeine. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Concomitant use of barbiturates, alcohol, or other CNS depressants may increase the risk of hypoventilation, airway obstruction, desaturation, or apnea and may contribute to profound and/or prolonged drug effect.
  
  midazolam intranasal, carisoprodol. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Concomitant use of barbiturates, alcohol, or other CNS depressants may increase the risk of hypoventilation, airway obstruction, desaturation, or apnea and may contribute to profound and/or prolonged drug effect.

• midodrine

  codeine increases and midodrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• milnacipran

  milnacipran, aspirin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• mirtazapine

  carisoprodol and mirtazapine both increase sedation. Use Caution/Monitor.

• mirabegron

  mirabegron will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

• mirtazapine

  codeine and mirtazapine both increase sedation. Use Caution/Monitor.

• mistletoe

  aspirin increases and mistletoe decreases anticoagulation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• modafinil

  codeine increases and modafinil decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• moexipril

  moexipril, aspirin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly with high dose aspirin, in elderly or volume depleted individuals.

• morphine

  codeine and morphine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and morphine both increase sedation. Use Caution/Monitor.

• motherwort

  codeine and motherwort both increase sedation. Use Caution/Monitor.
  
  carisoprodol and motherwort both increase sedation. Use Caution/Monitor.

• moxisylyte

  aspirin decreases effects of moxisylyte by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.

• moxonidine

  codeine and moxonidine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and moxonidine both increase sedation. Use Caution/Monitor.

• mycophenolate

  aspirin will increase the level or effect of mycophenolate by acidic (anionic) drug competition for renal tubular clearance. Use Caution/Monitor.

• nabilone

  codeine and nabilone both increase sedation. Use Caution/Monitor.
  
  carisoprodol and nabilone both increase sedation. Use Caution/Monitor.

• nabumetone

  aspirin and nabumetone both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and nabumetone both increase serum potassium. Use Caution/Monitor.

• nadolol

  nadolol and aspirin both increase serum potassium. Use Caution/Monitor.
  
  aspirin decreases effects of nadolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.

• nafcillin

  nafcillin, aspirin. Either increases levels of the other by plasma protein binding competition. Use Caution/Monitor.
  
  nafcillin, aspirin. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor.

• nalbuphine

  codeine and nalbuphine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and nalbuphine both increase sedation. Use Caution/Monitor.

• naproxen

  aspirin and naproxen both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and naproxen both increase serum potassium. Use Caution/Monitor.

• nebivolol

  nebivolol and aspirin both increase serum potassium. Use Caution/Monitor.
  
  aspirin decreases effects of nebivolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.

• nefazodone

  nefazodone, aspirin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• nettle

  aspirin increases and nettle decreases anticoagulation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• nitazoxanide

  nitazoxanide, aspirin. Either increases levels of the other by Mechanism: plasma protein binding competition. Use Caution/Monitor.

• nitroglycerin rectal

  aspirin will increase the level or effect of nitroglycerin rectal by Other (see comment). Use Caution/Monitor. The pharmacological effects of nitroglycerin may be enhanced by concomitant administration of aspirin.

• nitroglycerin sublingual

  aspirin increases effects of nitroglycerin sublingual by additive vasodilation. Use Caution/Monitor. Vasodilatory and hemodynamic effects of NTG may be enhanced by coadministration with aspirin (additive effect desirable for emergent treatment).

• norepinephrine

  aspirin increases and norepinephrine decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  codeine increases and norepinephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• nortriptyline

  carisoprodol and nortriptyline both increase sedation. Use Caution/Monitor.

• olmesartan

  olmesartan and aspirin both increase serum potassium. Use Caution/Monitor.
  
  aspirin decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  olmesartan, aspirin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.

• nortriptyline

  codeine and nortriptyline both increase sedation. Use Caution/Monitor.

• olanzapine

  codeine and olanzapine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and olanzapine both increase sedation. Use Caution/Monitor.

• oliceridine

  oliceridine, carisoprodol. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.
  
  carisoprodol increases toxicity of oliceridine by Other (see comment). Modify Therapy/Monitor Closely. Comment: Anticholinergic drugs may increase risk of urinary retention and/or severe constipation, which may lead to paralytic ileus. Monitor for signs of urinary retention or reduced gastric motility if oliceridine is coadministered with anticholinergics.
  
  oliceridine, codeine. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

• ombitasvir/paritaprevir/ritonavir & dasabuvir (DSC)

  ombitasvir/paritaprevir/ritonavir & dasabuvir (DSC) decreases effects of carisoprodol by unspecified interaction mechanism. Modify Therapy/Monitor Closely. Increase dose if clinically indicated.

• omega 3 carboxylic acids

  omega 3 carboxylic acids, aspirin. Other (see comment). Use Caution/Monitor. Comment: Patients taking omega-3 acids and an anticoagulant or other drug affecting coagulation should be monitored periodically due to potential increased risk of bleeding.

• omega 3 fatty acids

  omega 3 fatty acids, aspirin. Other (see comment). Use Caution/Monitor. Comment: Patients taking omega-3-fatty acids and an anticoagulant or other drug affecting coagulation should be monitored periodically due to potential increased risk of bleeding. .

• opium tincture

  codeine and opium tincture both increase sedation. Use Caution/Monitor.

• opium tincture

  carisoprodol and opium tincture both increase sedation. Use Caution/Monitor.

• orphenadrine

  carisoprodol and orphenadrine both increase sedation. Use Caution/Monitor.
  
  orphenadrine and codeine both increase sedation. Use Caution/Monitor.

• ospemifene

  aspirin, ospemifene. Either increases levels of the other by plasma protein binding competition. Modify Therapy/Monitor Closely.

• oxacillin

  oxacillin, aspirin. Either increases levels of the other by plasma protein binding competition. Use Caution/Monitor.
  
  oxacillin, aspirin. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor.

• oxaprozin

  aspirin and oxaprozin both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and oxaprozin both increase serum potassium. Use Caution/Monitor.

• oxazepam

  oxazepam and codeine both increase sedation. Use Caution/Monitor.
  
  oxazepam and carisoprodol both increase sedation. Use Caution/Monitor.

• oxycodone

  carisoprodol and oxycodone both increase sedation. Use Caution/Monitor.
  
  codeine and oxycodone both increase sedation. Use Caution/Monitor.

• oxymorphone

  codeine and oxymorphone both increase sedation. Use Caution/Monitor.
  
  carisoprodol and oxymorphone both increase sedation. Use Caution/Monitor.

• paliperidone

  carisoprodol and paliperidone both increase sedation. Use Caution/Monitor.
  
  codeine and paliperidone both increase sedation. Use Caution/Monitor.

• panax ginseng

  aspirin and panax ginseng both increase anticoagulation. Use Caution/Monitor.

• papaveretum

  codeine and papaveretum both increase sedation. Use Caution/Monitor.
  
  carisoprodol and papaveretum both increase sedation. Use Caution/Monitor.

• papaverine

  carisoprodol and papaverine both increase sedation. Use Caution/Monitor.
  
  codeine and papaverine both increase sedation. Use Caution/Monitor.

• parecoxib

  aspirin and parecoxib both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and parecoxib both increase serum potassium. Use Caution/Monitor.

• paroxetine

  paroxetine, aspirin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.
  
  paroxetine will decrease the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• pau d'arco

  aspirin and pau d'arco both increase anticoagulation. Use Caution/Monitor.

• peginterferon alfa 2b

  peginterferon alfa 2b, codeine. Other (see comment). Use Caution/Monitor. Comment: When patients are administered peginterferon alpha-2b with CYP2D6 substrates, the therapeutic effect of these drugs may be altered. Peginterferon alpha-2b may increase or decrease levels of CYP2D6 substrate.

• pegvisomant

  codeine decreases effects of pegvisomant by unknown mechanism. Use Caution/Monitor.

• pentazocine

  codeine and pentazocine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and pentazocine both increase sedation. Use Caution/Monitor.

• pegaspargase

  pegaspargase increases effects of aspirin by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of bleeding events.

• pentobarbital

  pentobarbital and carisoprodol both increase sedation. Use Caution/Monitor.
  
  pentobarbital and codeine both increase sedation. Use Caution/Monitor.

• penbutolol

  penbutolol and aspirin both increase serum potassium. Use Caution/Monitor.
  
  aspirin decreases effects of penbutolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.

• penicillin G aqueous

  penicillin G aqueous, aspirin. Either increases levels of the other by plasma protein binding competition. Use Caution/Monitor.
  
  penicillin G aqueous, aspirin. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor.

• perampanel

  perampanel and codeine both increase sedation. Use Caution/Monitor.

• perindopril

  perindopril, aspirin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly with high doses of aspirin,in elderly or volume depleted individuals.

• perphenazine

  carisoprodol and perphenazine both increase sedation. Use Caution/Monitor.

• perphenazine

  codeine and perphenazine both increase sedation. Use Caution/Monitor.

• phendimetrazine

  codeine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• phenindione

  phenindione and aspirin both increase anticoagulation. Modify Therapy/Monitor Closely.

• phenobarbital

  phenobarbital and codeine both increase sedation. Use Caution/Monitor.
  
  phenobarbital and carisoprodol both increase sedation. Use Caution/Monitor.

• phenoxybenzamine

  aspirin decreases effects of phenoxybenzamine by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.

• phentermine

  codeine increases and phentermine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• phentolamine

  aspirin decreases effects of phentolamine by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.

• phenylephrine PO

  carisoprodol increases and phenylephrine PO decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. .

• phenylephrine

  codeine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• phenylephrine PO

  codeine increases and phenylephrine PO decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. .

• pholcodine

  carisoprodol and pholcodine both increase sedation. Use Caution/Monitor.
  
  codeine and pholcodine both increase sedation. Use Caution/Monitor.

• phytoestrogens

  aspirin and phytoestrogens both increase anticoagulation. Use Caution/Monitor.

• pimozide

  codeine and pimozide both increase sedation. Use Caution/Monitor.
  
  carisoprodol and pimozide both increase sedation. Use Caution/Monitor.

• pindolol

  pindolol and aspirin both increase serum potassium. Use Caution/Monitor.
  
  aspirin decreases effects of pindolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.

• pirbuterol

  aspirin increases and pirbuterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  codeine increases and pirbuterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• piroxicam

  aspirin and piroxicam both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and piroxicam both increase serum potassium. Use Caution/Monitor.

• prabotulinumtoxinA

  carisoprodol increases effects of prabotulinumtoxinA by pharmacodynamic synergism. Use Caution/Monitor. Muscle relaxants may enhance botulinum toxin effects. Closely monitor for increased neuromuscular blockade.

• pivmecillinam

  pivmecillinam, aspirin. Either increases levels of the other by plasma protein binding competition. Use Caution/Monitor.
  
  pivmecillinam, aspirin. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor.

• potassium acid phosphate

  aspirin and potassium acid phosphate both increase serum potassium. Modify Therapy/Monitor Closely.

• potassium chloride

  aspirin and potassium chloride both increase serum potassium. Modify Therapy/Monitor Closely.

• potassium citrate

  aspirin and potassium citrate both increase serum potassium. Use Caution/Monitor.

• potassium iodide

  potassium iodide and aspirin both increase serum potassium. Use Caution/Monitor.

• prasugrel

  aspirin, prasugrel. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; monitor closely.

• prazosin

  aspirin decreases effects of prazosin by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.

• prednisolone

  aspirin, prednisolone. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of GI ulceration.

• prednisone

  aspirin, prednisone. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of GI ulceration.

• pregabalin

  pregabalin, codeine. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of CNS depressants can result in serious, life-threatening, and fatal respiratory depression. Use lowest dose possible and monitor for respiratory depression and sedation.

• primidone

  primidone and carisoprodol both increase sedation. Use Caution/Monitor.
  
  primidone and codeine both increase sedation. Use Caution/Monitor.

• prochlorperazine

  codeine and prochlorperazine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and prochlorperazine both increase sedation. Use Caution/Monitor.

• promethazine

  promethazine and carisoprodol both increase sedation. Use Caution/Monitor.
  
  promethazine and codeine both increase sedation. Use Caution/Monitor.

• propofol

  propofol and carisoprodol both increase sedation. Use Caution/Monitor.
  
  propofol and codeine both increase sedation. Use Caution/Monitor.

• propranolol

  propranolol and aspirin both increase serum potassium. Use Caution/Monitor.
  
  aspirin decreases effects of propranolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.

• propylhexedrine

  codeine increases and propylhexedrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  carisoprodol increases and propylhexedrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• protamine

  protamine and aspirin both increase anticoagulation. Modify Therapy/Monitor Closely.

• protriptyline

  codeine and protriptyline both increase sedation. Use Caution/Monitor.
  
  carisoprodol and protriptyline both increase sedation. Use Caution/Monitor.

• quazepam

  quazepam and codeine both increase sedation. Use Caution/Monitor.
  
  quazepam and carisoprodol both increase sedation. Use Caution/Monitor.

• quetiapine

  codeine and quetiapine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and quetiapine both increase sedation. Use Caution/Monitor.

• quinapril

  quinapril, aspirin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly with high doses of aspirin, in elderly or volume depleted individuals.

• quinidine

  quinidine will decrease the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• ramelteon

  carisoprodol and ramelteon both increase sedation. Use Caution/Monitor.

• ramelteon

  codeine and ramelteon both increase sedation. Use Caution/Monitor.

• ramipril

  ramipril, aspirin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly with high doses of aspirin, in elderly or volume depleted individuals.

• reishi

  aspirin and reishi both increase anticoagulation. Use Caution/Monitor.

• remimazolam

  remimazolam, codeine. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely. Coadministration may result in profound sedation, respiratory depression, coma, and/or death. Continuously monitor vital signs during sedation and recovery period if coadministered. Carefully titrate remimazolam dose if administered with opioid analgesics and/or sedative/hypnotics.
  
  remimazolam, carisoprodol. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely. Coadministration may result in profound sedation, respiratory depression, coma, and/or death. Continuously monitor vital signs during sedation and recovery period if coadministered. Carefully titrate remimazolam dose if administered with opioid analgesics and/or sedative/hypnotics.

• reteplase

  aspirin, reteplase. Either increases toxicity of the other by anticoagulation. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; monitor closely.

• ribociclib

  ribociclib will increase the level or effect of codeine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• risperidone

  carisoprodol and risperidone both increase sedation. Use Caution/Monitor.

• risperidone

  codeine and risperidone both increase sedation. Use Caution/Monitor.

• ritonavir

  ritonavir will decrease the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• rivaroxaban

  aspirin, rivaroxaban. Either increases toxicity of the other by anticoagulation. Use Caution/Monitor. Both drugs have the potential to cause bleeding. The need for simultaneous use of low-dose aspirin (<100 mg/day) with anticoagulants are common for patients with cardiovascular disease, but may result in increased bleeding; monitor closely. Promptly evaluate any signs or symptoms of blood loss if treated concomitantly with low-dose aspirin. Avoid coadministration with chronic use of higher dose aspirin.

• rivastigmine

  rivastigmine increases toxicity of aspirin by pharmacodynamic synergism. Use Caution/Monitor. Monitor patients for symptoms of active or occult gastrointestinal bleeding.

• rolapitant

  rolapitant will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Rolapitant may increase plasma concentrations of CYP2D6 substrates for at least 28 days following rolapitant administration.

• rucaparib

  rucaparib will increase the level or effect of carisoprodol by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Adjust dosage of CYP2C19 substrates, if clinically indicated.

• sacubitril/valsartan

  sacubitril/valsartan and aspirin both increase serum potassium. Use Caution/Monitor.
  
  sacubitril/valsartan, aspirin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  aspirin decreases effects of sacubitril/valsartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.

• salicylates (non-asa)

  aspirin and salicylates (non-asa) both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and salicylates (non-asa) both increase serum potassium. Use Caution/Monitor.

• salmeterol

  codeine increases and salmeterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  aspirin increases and salmeterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• salsalate

  aspirin and salsalate both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and salsalate both increase serum potassium. Use Caution/Monitor.

• scullcap

  codeine and scullcap both increase sedation. Use Caution/Monitor.
  
  carisoprodol and scullcap both increase sedation. Use Caution/Monitor.

• saw palmetto

  saw palmetto increases toxicity of aspirin by unspecified interaction mechanism. Use Caution/Monitor. May increase risk of bleeding.

• secobarbital

  secobarbital and codeine both increase sedation. Use Caution/Monitor.
  
  secobarbital and carisoprodol both increase sedation. Use Caution/Monitor.

• selegiline

  selegiline increases toxicity of codeine by unknown mechanism. Modify Therapy/Monitor Closely. Potential for increased CNS depression, drowsiness, dizziness or hypotension, so use with any MAOI should be cautious.

• selumetinib

  aspirin and selumetinib both increase anticoagulation. Modify Therapy/Monitor Closely. An increased risk of bleeding may occur in patients taking a vitamin-K antagonist or an antiplatelet agent with selumetinib. Monitor for bleeding and INR or PT in patients coadministered a vitamin-K antagonist or an antiplatelet agent with selumetinib.

• sertraline

  sertraline, aspirin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• Siberian ginseng

  aspirin and Siberian ginseng both increase anticoagulation. Use Caution/Monitor.

• shepherd's purse

  carisoprodol and shepherd's purse both increase sedation. Use Caution/Monitor.

• sertraline

  sertraline decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• sevoflurane

  sevoflurane and codeine both increase sedation. Use Caution/Monitor.

• shepherd's purse

  codeine and shepherd's purse both increase sedation. Use Caution/Monitor.

• silodosin

  aspirin decreases effects of silodosin by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.

• sodium picosulfate/magnesium oxide/anhydrous citric acid

  aspirin, sodium picosulfate/magnesium oxide/anhydrous citric acid. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May be associated with fluid and electrolyte imbalances.

• sodium sulfate/?magnesium sulfate/potassium chloride

  sodium sulfate/?magnesium sulfate/potassium chloride increases toxicity of aspirin by Other (see comment). Use Caution/Monitor. Comment: Coadministration with medications that cause fluid and electrolyte abnormalities may increase the risk of adverse events of seizure, arrhythmias, and renal impairment.

• sodium sulfate/potassium sulfate/magnesium sulfate

  sodium sulfate/potassium sulfate/magnesium sulfate increases toxicity of aspirin by Other (see comment). Use Caution/Monitor. Comment: Coadministration with medications that cause fluid and electrolyte abnormalities may increase the risk of adverse events of seizure, arrhythmias, and renal impairment.

• sotalol

  sotalol and aspirin both increase serum potassium. Use Caution/Monitor.
  
  aspirin decreases effects of sotalol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.

• sparsentan

  sparsentan will decrease the level or effect of carisoprodol by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. Sparsentan (a CYP2C19 inducer) decreases exposure of CYP2C19 substrates and reduces efficacy related to these substrates.
  
  aspirin and sparsentan both increase nephrotoxicity and/or ototoxicity. Use Caution/Monitor. Coadministration of NSAIDS, including selective COX-2 inhibitors, may result in deterioration of kidney function (eg, possible kidney failure). Monitor for signs of worsening renal function with concomitant use with NSAIDs.

• spironolactone

  spironolactone and aspirin both increase serum potassium. Modify Therapy/Monitor Closely.
  
  aspirin decreases effects of spironolactone by unspecified interaction mechanism. Use Caution/Monitor. When used concomitantly, spironolactone dose may need to be titrated to higher maintenance dose and the patient should be observed closely to determine if the desired effect is obtained.

• stiripentol

  stiripentol, carisoprodol. Either increases effects of the other by sedation. Use Caution/Monitor. Concurrent use of medications with CNS depressant effects together with thalidomide should be avoided due to the risk for additive sedative effects.
  
  stiripentol, codeine. Either increases effects of the other by sedation. Use Caution/Monitor. Concomitant use stiripentol with other CNS depressants, including alcohol, may increase the risk of sedation and somnolence.
  
  stiripentol will increase the level or effect of carisoprodol by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Consider reducing the dose of CYP2C19 substrates, if adverse reactions are experienced when administered concomitantly with stiripentol.

• succinylcholine

  aspirin and succinylcholine both increase serum potassium. Use Caution/Monitor.

• sufentanil

  codeine and sufentanil both increase sedation. Use Caution/Monitor.
  
  carisoprodol and sufentanil both increase sedation. Use Caution/Monitor.

• sulfamethoxazole

  aspirin, sulfamethoxazole. Either increases effects of the other by plasma protein binding competition. Use Caution/Monitor. Due to high protein binding capacity of both drugs, one may displace the other when coadministered leading to an enhanced effect of the displaced drug; risk is low with low dose aspirin.

• sulfasalazine

  aspirin and sulfasalazine both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and sulfasalazine both increase serum potassium. Use Caution/Monitor.

• sulindac

  aspirin and sulindac both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and sulindac both increase serum potassium. Use Caution/Monitor.

• suvorexant

  suvorexant and codeine both increase sedation. Modify Therapy/Monitor Closely. Dosage adjustments of suvorexant and concomitant CNS depressants may be necessary

• tafluprost

  tafluprost, aspirin. unspecified interaction mechanism. Use Caution/Monitor. There are conflicting reports from studies of either increased or decreased IOP when ophthalmic prostaglandins are coadministered with NSAIDs (either systemic or ophthalmic).

• tapentadol

  carisoprodol and tapentadol both increase sedation. Use Caution/Monitor.

• tapentadol

  codeine and tapentadol both increase sedation. Use Caution/Monitor.

• tecovirimat

  tecovirimat will increase the level or effect of carisoprodol by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. Tecovirimat is a weak inhibitor of CYP2C8 and CYP2C19. Monitor for adverse effects if coadministered with sensitive substrates of these enzymes.

• telmisartan

  telmisartan and aspirin both increase serum potassium. Use Caution/Monitor.
  
  aspirin decreases effects of telmisartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  telmisartan, aspirin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.

• temazepam

  temazepam and codeine both increase sedation. Use Caution/Monitor.
  
  temazepam and carisoprodol both increase sedation. Use Caution/Monitor.

• temocillin

  temocillin, aspirin. Either increases levels of the other by plasma protein binding competition. Use Caution/Monitor.
  
  temocillin, aspirin. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor.

• tenecteplase

  aspirin, tenecteplase. Either increases toxicity of the other by anticoagulation. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; monitor closely.

• terazosin

  aspirin decreases effects of terazosin by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.

• terbinafine

  terbinafine will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Assess need to reduce dose of CYP2D6-metabolized drug.

• terbutaline

  aspirin increases and terbutaline decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• thioridazine

  carisoprodol and thioridazine both increase sedation. Use Caution/Monitor.

• terbutaline

  codeine increases and terbutaline decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• thioridazine

  thioridazine decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.
  
  codeine and thioridazine both increase sedation. Use Caution/Monitor.

• thiothixene

  codeine and thiothixene both increase sedation. Use Caution/Monitor.
  
  carisoprodol and thiothixene both increase sedation. Use Caution/Monitor.

• ticagrelor

  aspirin, ticagrelor. Other (see comment). Use Caution/Monitor. Comment: Maintenance doses of aspirin above 100 mg decreases effectiveness of ticagrelor. Therefore, after the initial loading dose of aspirin (usually 325 mg), use ticagrelor with a maintenance dose of aspirin of 75-100 mg.

• ticarcillin

  ticarcillin, aspirin. Either increases levels of the other by plasma protein binding competition. Use Caution/Monitor.
  
  ticarcillin, aspirin. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor.

• ticlopidine

  ticlopidine decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• timolol

  timolol and aspirin both increase serum potassium. Use Caution/Monitor.
  
  aspirin decreases effects of timolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.

• tirofiban

  aspirin, tirofiban. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; monitor closely.

• tobramycin inhaled

  tobramycin inhaled and aspirin both increase nephrotoxicity and/or ototoxicity. Modify Therapy/Monitor Closely. Avoid concurrent or sequential use to decrease risk for ototoxicity

• tolazamide

  aspirin increases effects of tolazamide by unknown mechanism. Use Caution/Monitor. Risk of hypoglycemia.

• tolbutamide

  aspirin increases effects of tolbutamide by unknown mechanism. Use Caution/Monitor. Risk of hypoglycemia.

• tolfenamic acid

  aspirin and tolfenamic acid both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and tolfenamic acid both increase serum potassium. Use Caution/Monitor.

• tolmetin

  aspirin and tolmetin both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and tolmetin both increase serum potassium. Use Caution/Monitor.

• tolvaptan

  aspirin and tolvaptan both increase serum potassium. Use Caution/Monitor.

• topiramate

  carisoprodol and topiramate both increase sedation. Modify Therapy/Monitor Closely.

• topiramate

  codeine and topiramate both increase sedation. Modify Therapy/Monitor Closely.

• torsemide

  aspirin increases and torsemide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• tramadol

  carisoprodol and tramadol both increase sedation. Use Caution/Monitor.
  
  codeine and tramadol both increase sedation. Use Caution/Monitor.

• trandolapril

  trandolapril, aspirin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly with high dose aspirin, in elderly and volume depleted.

• tranylcypromine

  tranylcypromine decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• travoprost ophthalmic

  travoprost ophthalmic, aspirin. unspecified interaction mechanism. Use Caution/Monitor. There are conflicting reports from studies of either increased or decreased IOP when ophthalmic prostaglandins are coadministered with NSAIDs (either systemic or ophthalmic).

• trazodone

  trazodone, aspirin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.
  
  carisoprodol and trazodone both increase sedation. Use Caution/Monitor.

• trazodone

  codeine and trazodone both increase sedation. Use Caution/Monitor.

• triamcinolone acetonide injectable suspension

  aspirin, triamcinolone acetonide injectable suspension. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Aspirin in conjunction with corticosteroids in hypoprothrombinemia should used with caution. Clearance of salicylates may increase with concurrent use of corticosteroids.

• triamterene

  triamterene and aspirin both increase serum potassium. Modify Therapy/Monitor Closely.

• triazolam

  triazolam and carisoprodol both increase sedation. Use Caution/Monitor.
  
  triazolam and codeine both increase sedation. Use Caution/Monitor.

• triclabendazole

  triclabendazole will increase the level or effect of carisoprodol by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. If plasma concentrations of the CYP2C19 substrates are elevated during triclabendazole, recheck plasma concentration of the CYP2C19 substrates after discontinuation of triclabendazole.

• triclofos

  triclofos and codeine both increase sedation. Use Caution/Monitor.

• triclofos

  triclofos and carisoprodol both increase sedation. Use Caution/Monitor.

• trifluoperazine

  codeine and trifluoperazine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and trifluoperazine both increase sedation. Use Caution/Monitor.

• trimipramine

  codeine and trimipramine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and trimipramine both increase sedation. Use Caution/Monitor.

• triprolidine

  triprolidine and codeine both increase sedation. Use Caution/Monitor.

• valproic acid

  aspirin increases levels of valproic acid by plasma protein binding competition. Use Caution/Monitor.

• valsartan

  valsartan and aspirin both increase serum potassium. Use Caution/Monitor.
  
  aspirin decreases effects of valsartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  valsartan, aspirin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.

• venlafaxine

  venlafaxine, aspirin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• voclosporin

  voclosporin, aspirin. Either increases toxicity of the other by nephrotoxicity and/or ototoxicity. Modify Therapy/Monitor Closely. Coadministration with drugs associated with nephrotoxicity may increase the risk for acute and/or chronic nephrotoxicity.

• vorapaxar

  aspirin, vorapaxar. Either increases effects of the other by anticoagulation. Use Caution/Monitor. Coadministration of anticoagulants, antiplatelets, or other drug affecting coagulation should be monitored periodically due to potential increased risk of bleeding.
  
  aspirin, vorapaxar. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Additive antiplatelet effect may occur.

• vortioxetine

  aspirin, vortioxetine. Either increases effects of the other by anticoagulation. Use Caution/Monitor. Risk minimal with low-dose aspirin.

• warfarin

  aspirin increases effects of warfarin by anticoagulation. Modify Therapy/Monitor Closely. Avoid coadministration of chronic high-dose aspirin. Aspirin's antiplatelet properties may increase anticoagulation effect of warfarin. The need for simultaneous use of low-dose aspirin and warfarin is common for patients with cardiovascular disease. .

• xylometazoline

  carisoprodol increases and xylometazoline decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• venlafaxine

  venlafaxine will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

• xylometazoline

  codeine increases and xylometazoline decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• yohimbine

  codeine increases and yohimbine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• zanubrutinib

  aspirin, zanubrutinib. Either increases effects of the other by anticoagulation. Modify Therapy/Monitor Closely. Zanubrutinib-induced cytopenias increases risk of hemorrhage. Coadministration of zanubritinib with antiplatelets or anticoagulants may further increase this risk.

• ziconotide

  codeine and ziconotide both increase sedation. Use Caution/Monitor.
  
  carisoprodol and ziconotide both increase sedation. Use Caution/Monitor.

• ziprasidone

  codeine and ziprasidone both increase sedation. Use Caution/Monitor.
  
  carisoprodol and ziprasidone both increase sedation. Use Caution/Monitor.

• zotepine

  aspirin decreases effects of zotepine by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.
  
  codeine and zotepine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and zotepine both increase sedation. Use Caution/Monitor.

Minor (102)

• aceclofenac

  aceclofenac will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• acemetacin

  acemetacin will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• acetazolamide

  aspirin will decrease the level or effect of acetazolamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• acyclovir

  aspirin will increase the level or effect of acyclovir by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• alendronate

  aspirin, alendronate. Either increases toxicity of the other by pharmacodynamic synergism. Minor/Significance Unknown. Increased risk of GI ulceration.

• aluminum hydroxide

  aluminum hydroxide, aspirin. Mechanism: passive renal tubular reabsorption due to increased pH. Minor/Significance Unknown. Salicylate levels increased at moderate doses; salicylate levels decreased at large doses (d/t increased renal excretion of unchanged salicylic acid).

• amikacin

  aspirin increases levels of amikacin by decreasing renal clearance. Minor/Significance Unknown. Interaction mainly occurs in preterm infants.

• aminohippurate sodium

  aspirin will increase the level or effect of aminohippurate sodium by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• anamu

  aspirin and anamu both increase anticoagulation. Minor/Significance Unknown.

• anastrozole

  aspirin will decrease the level or effect of anastrozole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• ascorbic acid

  ascorbic acid will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
  
  aspirin decreases levels of ascorbic acid by increasing renal clearance. Minor/Significance Unknown.
  
  ascorbic acid increases levels of aspirin by decreasing renal clearance. Minor/Significance Unknown.

• asenapine

  asenapine will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• balsalazide

  aspirin will increase the level or effect of balsalazide by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• bendroflumethiazide

  bendroflumethiazide will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• bismuth subsalicylate

  bismuth subsalicylate increases effects of aspirin by pharmacodynamic synergism. Minor/Significance Unknown.

• brimonidine

  brimonidine increases effects of codeine by pharmacodynamic synergism. Minor/Significance Unknown. Increased CNS depression.

• bumetanide

  aspirin, bumetanide. Other (see comment). Minor/Significance Unknown. Comment: Salicylates are less likely than other NSAIDs to interact w/bumetanide.

• calcium carbonate

  calcium carbonate, aspirin. Mechanism: passive renal tubular reabsorption due to increased pH. Minor/Significance Unknown. Salicylate levels increased at moderate doses; salicylate levels decreased at large doses (d/t increased renal excretion of unchanged salicylic acid).

• cefadroxil

  cefadroxil will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• cefamandole

  cefamandole will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• cefepime

  cefepime will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• cefixime

  cefixime will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• cefpirome

  cefpirome will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• cefprozil

  cefprozil will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• ceftazidime

  ceftazidime will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• ceftibuten

  ceftibuten will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• celecoxib

  aspirin will increase the level or effect of celecoxib by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• cephalexin

  cephalexin will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• ceritinib

  aspirin will decrease the level or effect of ceritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• chlorothiazide

  chlorothiazide will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• chlorpropamide

  aspirin will increase the level or effect of chlorpropamide by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
  
  aspirin increases effects of chlorpropamide by plasma protein binding competition. Minor/Significance Unknown. Large dose of salicylate.

• chlorthalidone

  chlorthalidone will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• choline magnesium trisalicylate

  aspirin will increase the level or effect of choline magnesium trisalicylate by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• chromium

  aspirin increases levels of chromium by unspecified interaction mechanism. Minor/Significance Unknown.

• cortisone

  cortisone decreases levels of aspirin by increasing renal clearance. Minor/Significance Unknown.

• creatine

  creatine, aspirin. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. (Theoretical interaction) Combination may have additive nephrotoxic effects.

• cyanocobalamin

  aspirin decreases levels of cyanocobalamin by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• cyclopenthiazide

  cyclopenthiazide will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• cyclophosphamide

  aspirin will decrease the level or effect of cyclophosphamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• danshen

  aspirin and danshen both increase anticoagulation. Minor/Significance Unknown.

• deflazacort

  deflazacort decreases levels of aspirin by increasing renal clearance. Minor/Significance Unknown.

• devil's claw

  aspirin and devil's claw both increase anticoagulation. Minor/Significance Unknown.

• dexamethasone

  dexamethasone decreases levels of aspirin by increasing renal clearance. Minor/Significance Unknown.

• dextroamphetamine

  dextroamphetamine increases effects of codeine by unspecified interaction mechanism. Minor/Significance Unknown.

• diclofenac

  aspirin will increase the level or effect of diclofenac by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• diclofenac topical

  diclofenac topical, aspirin. Either increases effects of the other by pharmacodynamic synergism. Minor/Significance Unknown. Although low, there is systemic exposure to diclofenac topical; theoretically, concomitant administration with systemic NSAIDS or aspirin may result in increased NSAID adverse effects.

• diflunisal

  aspirin will increase the level or effect of diflunisal by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• diltiazem

  diltiazem increases effects of aspirin by unknown mechanism. Minor/Significance Unknown. Enhanced antiplatelet activity.

• eplerenone

  aspirin decreases effects of eplerenone by pharmacodynamic antagonism. Minor/Significance Unknown. NSAIDs decrease prostaglandin synthesis.

• ethanol

  ethanol increases toxicity of aspirin by pharmacodynamic synergism. Minor/Significance Unknown. Increased risk of GI bleeding.

• etodolac

  aspirin will increase the level or effect of etodolac by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• eucalyptus

  codeine and eucalyptus both increase sedation. Minor/Significance Unknown.
  
  carisoprodol and eucalyptus both increase sedation. Minor/Significance Unknown.

• fenbufen

  aspirin will increase the level or effect of fenbufen by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• fenoprofen

  aspirin will increase the level or effect of fenoprofen by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• feverfew

  aspirin decreases effects of feverfew by pharmacodynamic antagonism. Minor/Significance Unknown.

• fludrocortisone

  fludrocortisone decreases levels of aspirin by increasing renal clearance. Minor/Significance Unknown.

• fluoxetine

  fluoxetine decreases effects of codeine by decreasing metabolism. Minor/Significance Unknown. Decreased conversion of codeine to active metabolite morphine.

• flurbiprofen

  aspirin will increase the level or effect of flurbiprofen by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• folic acid

  aspirin decreases levels of folic acid by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• furosemide

  aspirin decreases effects of furosemide by pharmacodynamic antagonism. Minor/Significance Unknown. NSAIDs decrease prostaglandin synthesis.

• ganciclovir

  aspirin will increase the level or effect of ganciclovir by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• gentamicin

  aspirin increases levels of gentamicin by decreasing renal clearance. Minor/Significance Unknown. Interaction mainly occurs in preterm infants.

• glimepiride

  aspirin increases effects of glimepiride by plasma protein binding competition. Minor/Significance Unknown. Large dose of salicylate.

• glipizide

  aspirin increases effects of glipizide by plasma protein binding competition. Minor/Significance Unknown. Large dose of salicylate.

• glyburide

  aspirin increases effects of glyburide by plasma protein binding competition. Minor/Significance Unknown. Large dose of salicylate.

• hydrochlorothiazide

  hydrochlorothiazide will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• hydrocortisone

  hydrocortisone decreases levels of aspirin by increasing renal clearance. Minor/Significance Unknown.

• ibuprofen

  aspirin will increase the level or effect of ibuprofen by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• imidapril

  aspirin decreases effects of imidapril by pharmacodynamic antagonism. Minor/Significance Unknown. NSAIDs decrease prostaglandin synthesis.

• indapamide

  indapamide will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• indomethacin

  aspirin will increase the level or effect of indomethacin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• ketoprofen

  aspirin will increase the level or effect of ketoprofen by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• ketorolac

  aspirin will increase the level or effect of ketorolac by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• ketorolac intranasal

  aspirin will increase the level or effect of ketorolac intranasal by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• L-methylfolate

  aspirin decreases levels of L-methylfolate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• larotrectinib

  aspirin will decrease the level or effect of larotrectinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• levoketoconazole

  aspirin will decrease the level or effect of levoketoconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• lornoxicam

  aspirin will increase the level or effect of lornoxicam by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• meclofenamate

  aspirin will increase the level or effect of meclofenamate by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• mefenamic acid

  aspirin will increase the level or effect of mefenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• meloxicam

  aspirin will increase the level or effect of meloxicam by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• mesalamine

  aspirin will increase the level or effect of mesalamine by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• methyclothiazide

  methyclothiazide will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• methylprednisolone

  methylprednisolone decreases levels of aspirin by increasing renal clearance. Minor/Significance Unknown.

• metolazone

  metolazone will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• nabumetone

  aspirin will increase the level or effect of nabumetone by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• naproxen

  aspirin will increase the level or effect of naproxen by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• neomycin PO

  aspirin increases levels of neomycin PO by decreasing renal clearance. Minor/Significance Unknown. Interaction mainly occurs in preterm infants.

• noni juice

  aspirin and noni juice both increase serum potassium. Minor/Significance Unknown.

• ofloxacin

  ofloxacin, aspirin. Other (see comment). Minor/Significance Unknown. Comment: Risk of CNS stimulation/seizure. Mechanism: Displacement of GABA from receptors in brain.

• oxaprozin

  aspirin will increase the level or effect of oxaprozin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• parecoxib

  aspirin will increase the level or effect of parecoxib by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• paromomycin

  aspirin increases levels of paromomycin by decreasing renal clearance. Minor/Significance Unknown. Interaction mainly occurs in preterm infants.

• penicillin VK

  penicillin VK, aspirin. Either increases levels of the other by decreasing renal clearance. Minor/Significance Unknown.

• pentazocine

  aspirin, pentazocine. Either increases toxicity of the other by pharmacodynamic synergism. Minor/Significance Unknown. Possible risk of renal papillary necrosis w/chronic Tx.

• piperacillin

  piperacillin, aspirin. Either increases effects of the other by receptor binding competition. Minor/Significance Unknown. Salicylic acid could be displaced from protein binding sites or it could itself displace other protein-bound drugs and result in an enhanced effect of the displaced drug.

• piroxicam

  aspirin will increase the level or effect of piroxicam by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• prednisolone

  prednisolone decreases levels of aspirin by increasing renal clearance. Minor/Significance Unknown.

• prednisone

  prednisone decreases levels of aspirin by increasing renal clearance. Minor/Significance Unknown.

• rose hips

  rose hips will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
  
  aspirin decreases levels of rose hips by increasing renal clearance. Minor/Significance Unknown.
  
  rose hips increases levels of aspirin by decreasing renal clearance. Minor/Significance Unknown.

• sage

  carisoprodol and sage both increase sedation. Minor/Significance Unknown.

• salicylates (non-asa)

  aspirin will increase the level or effect of salicylates (non-asa) by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• abciximab

  Monitor Closely (1)aspirin, abciximab. Either increases toxicity of the other by anticoagulation. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; monitor closely.

• abiraterone

  Monitor Closely (1)abiraterone increases levels of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Avoid coadministration of abiraterone with substrates of CYP2D6. If alternative therapy cannot be used, exercise caution and consider a dose reduction of the CYP2D6 substrate.

• abobotulinumtoxinA

  Monitor Closely (1)carisoprodol increases effects of abobotulinumtoxinA by pharmacodynamic synergism. Use Caution/Monitor. Muscle relaxants may enhance botulinum toxin effects. Closely monitor for increased neuromuscular blockade.

• abrocitinib

  Contraindicated (1)abrocitinib and aspirin both increase anticoagulation. Contraindicated. Antiplatelet drugs, except for low-dose aspirin (=81 mg qDay), during the first 3 months of treatment are contraindicated.

• acalabrutinib

  Monitor Closely (1)acalabrutinib increases effects of aspirin by anticoagulation. Modify Therapy/Monitor Closely. Coadministration of acalabrutinib with antiplatelets or anticoagulants may further increase risk of hemorrhage. Monitor for signs of bleeding and consider the benefit-risk of withholding acalabrutinib for 3-7 days presurgery and postsurgery depending upon the type of surgery and the risk of bleeding.

• acebutolol

  Monitor Closely (2)aspirin decreases effects of acebutolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  acebutolol and aspirin both increase serum potassium. Use Caution/Monitor.

• aceclofenac

  Monitor Closely (2)aceclofenac and aspirin both increase anticoagulation. Use Caution/Monitor.
  
  aceclofenac and aspirin both increase serum potassium. Use Caution/Monitor.Minor (1)aceclofenac will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• acemetacin

  Monitor Closely (2)acemetacin and aspirin both increase anticoagulation. Use Caution/Monitor.
  
  acemetacin and aspirin both increase serum potassium. Use Caution/Monitor.Minor (1)acemetacin will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• acetazolamide

  Monitor Closely (2)acetazolamide, aspirin. Either increases levels of the other by Other (see comment). Use Caution/Monitor. Comment: Carbonic anhydrase inhibitors (CAIs) and salicylates inhibit each other's renal tubular secretion, resulting in increased plasma levels. CAIs also shift salicylates from plasma to the CNS, leading to potential neurotoxicity.
  
  acetazolamide, aspirin. Mechanism: passive renal tubular reabsorption due to increased pH. Use Caution/Monitor. Salicylate levels increased at moderate doses; risk of CNS toxicity. Salicylate levels decreased at large doses (d/t increased renal excretion of unchanged salicylic acid).Minor (1)aspirin will decrease the level or effect of acetazolamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• acrivastine

  Monitor Closely (1)acrivastine and carisoprodol both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)acrivastine and codeine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate

• acyclovir

  Minor (1)aspirin will increase the level or effect of acyclovir by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• agrimony

  Monitor Closely (1)aspirin and agrimony both increase anticoagulation. Use Caution/Monitor.

• albuterol

  Monitor Closely (2)codeine increases and albuterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  aspirin increases and albuterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• alendronate

  Minor (1)aspirin, alendronate. Either increases toxicity of the other by pharmacodynamic synergism. Minor/Significance Unknown. Increased risk of GI ulceration.

• alfalfa

  Monitor Closely (1)aspirin and alfalfa both increase anticoagulation. Use Caution/Monitor.

• alfentanil

  Monitor Closely (2)carisoprodol and alfentanil both increase sedation. Use Caution/Monitor.
  
  alfentanil and codeine both increase sedation. Use Caution/Monitor.

• alfuzosin

  Monitor Closely (1)aspirin decreases effects of alfuzosin by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.

• aliskiren

  Monitor Closely (1)aspirin will decrease the level or effect of aliskiren by Other (see comment). Use Caution/Monitor. In patients who are elderly, volume-depleted (including those on diuretic therapy), or with compromised renal function, coadministration of NSAIDs with drugs that affect RAAS may increase the risk of renal impairment (including acute renal failure) and cause loss of antihypertensive effect. Monitor renal function periodically.

• alprazolam

  Monitor Closely (2)alprazolam and codeine both increase sedation. Use Caution/Monitor.
  
  alprazolam and carisoprodol both increase sedation. Use Caution/Monitor.

• alteplase

  Monitor Closely (1)aspirin, alteplase. Either increases toxicity of the other by anticoagulation. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; monitor closely.

• aluminum hydroxide

  Minor (1)aluminum hydroxide, aspirin. Mechanism: passive renal tubular reabsorption due to increased pH. Minor/Significance Unknown. Salicylate levels increased at moderate doses; salicylate levels decreased at large doses (d/t increased renal excretion of unchanged salicylic acid).

• alvimopan

  Contraindicated (1)alvimopan, codeine. receptor binding competition. Contraindicated. Alvimopan is contraindicated in opioid tolerant patients (ie, those who have taken therapeutic doses of opioids for >7 consecutive days immediately prior to taking alvimopan). Patients recently exposed to opioids are expected to be more sensitive to the effects of alvimopan and therefore may experience abdominal pain, nausea and vomiting, and diarrhea. No significant interaction is expected with concurrent use of opioid analgesics and alvimopan in patients who received opioid analgesics for 7 or fewer consecutive days prior to alvimopan.

• American ginseng

  Monitor Closely (1)aspirin and American ginseng both increase anticoagulation. Use Caution/Monitor.

• amikacin

  Minor (1)aspirin increases levels of amikacin by decreasing renal clearance. Minor/Significance Unknown. Interaction mainly occurs in preterm infants.

• amiloride

  Monitor Closely (1)amiloride and aspirin both increase serum potassium. Modify Therapy/Monitor Closely.

• aminohippurate sodium

  Minor (1)aspirin will increase the level or effect of aminohippurate sodium by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• amiodarone

  Monitor Closely (1)amiodarone will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• amisulpride

  Monitor Closely (1)amisulpride and carisoprodol both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)amisulpride and codeine both increase sedation. Avoid or Use Alternate Drug.

• amitriptyline

  Monitor Closely (2)carisoprodol and amitriptyline both increase sedation. Use Caution/Monitor.
  
  codeine and amitriptyline both increase sedation. Use Caution/Monitor.

• amobarbital

  Monitor Closely (2)amobarbital and codeine both increase sedation. Use Caution/Monitor.
  
  amobarbital and carisoprodol both increase sedation. Use Caution/Monitor.

• amoxapine

  Monitor Closely (2)codeine and amoxapine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and amoxapine both increase sedation. Use Caution/Monitor.

• amoxicillin

  Monitor Closely (2)amoxicillin, aspirin. Either increases levels of the other by plasma protein binding competition. Use Caution/Monitor.
  
  amoxicillin, aspirin. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor.

• ampicillin

  Monitor Closely (1)ampicillin, aspirin. Either increases levels of the other by plasma protein binding competition. Use Caution/Monitor.

• anagrelide

  Monitor Closely (2)aspirin, anagrelide. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; increases risk of bleeding; monitor closely.
  
  anagrelide, aspirin. Either increases toxicity of the other by Mechanism: pharmacodynamic synergism. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; increases risk of bleeding; monitor closely.

• anamu

  Minor (1)aspirin and anamu both increase anticoagulation. Minor/Significance Unknown.

• anastrozole

  Minor (1)aspirin will decrease the level or effect of anastrozole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• antithrombin alfa

  Monitor Closely (2)aspirin, antithrombin alfa. Either increases toxicity of the other by anticoagulation. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; monitor closely.
  
  antithrombin alfa and aspirin both increase anticoagulation. Modify Therapy/Monitor Closely.

• antithrombin III

  Monitor Closely (2)aspirin, antithrombin III. Either increases toxicity of the other by anticoagulation. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; monitor closely.
  
  antithrombin III and aspirin both increase anticoagulation. Modify Therapy/Monitor Closely.

• apalutamide

  Serious - Use Alternative (1)apalutamide will decrease the level or effect of carisoprodol by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug. Coadministration of apalutamide, a strong CYP2C19 inducer, with drugs that are CYP2C19 substrates can result in lower exposure to these medications. Avoid or substitute another drug for these medications when possible. Evaluate for loss of therapeutic effect if medication must be coadministered.

• apixaban

  Monitor Closely (1)aspirin and apixaban both increase anticoagulation. Modify Therapy/Monitor Closely. Both drugs have the potential to cause bleeding. The need for simultaneous use of low-dose aspirin (<100 mg/day) with anticoagulants are common for patients with cardiovascular disease, but may result in increased bleeding; monitor closely. Promptly evaluate any signs or symptoms of blood loss if treated concomitantly with low-dose aspiriin. Avoid coadministration with chronic use of higher dose aspirin. In 1 trial (APPRAISE-2), therapy was terminated because of significantly increased bleeding when apixaban was administered with dual antiplatelet therapy (eg, aspirin plus clopidogrel) compared with single antiplatelet treatment

• apomorphine

  Monitor Closely (2)codeine and apomorphine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and apomorphine both increase sedation. Use Caution/Monitor.

• arformoterol

  Monitor Closely (2)codeine increases and arformoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  aspirin increases and arformoterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• argatroban

  Monitor Closely (2)aspirin, argatroban. Either increases toxicity of the other by anticoagulation. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; monitor closely.
  
  argatroban and aspirin both increase anticoagulation. Modify Therapy/Monitor Closely.

• aripiprazole

  Monitor Closely (2)codeine and aripiprazole both increase sedation. Use Caution/Monitor.
  
  carisoprodol and aripiprazole both increase sedation. Use Caution/Monitor.

• armodafinil

  Monitor Closely (1)codeine increases and armodafinil decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• artemether/lumefantrine

  Monitor Closely (1)artemether/lumefantrine will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

• ascorbic acid

  Minor (3)ascorbic acid will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
  
  aspirin decreases levels of ascorbic acid by increasing renal clearance. Minor/Significance Unknown.
  
  ascorbic acid increases levels of aspirin by decreasing renal clearance. Minor/Significance Unknown.

• asenapine

  Monitor Closely (2)asenapine and carisoprodol both increase sedation. Use Caution/Monitor.
  
  aspirin decreases effects of asenapine by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.Serious - Use Alternative (1)asenapine and codeine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequateMinor (1)asenapine will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• asenapine transdermal

  Monitor Closely (1)asenapine transdermal and carisoprodol both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)asenapine transdermal and codeine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate

• atenolol

  Monitor Closely (2)aspirin decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  atenolol and aspirin both increase serum potassium. Use Caution/Monitor.

• avapritinib

  Monitor Closely (1)avapritinib and carisoprodol both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)avapritinib and codeine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate

• azelastine

  Monitor Closely (2)azelastine and carisoprodol both increase sedation. Use Caution/Monitor.
  
  azelastine and codeine both increase sedation. Use Caution/Monitor.

• azficel-T

  Monitor Closely (1)azficel-T, aspirin. Other (see comment). Use Caution/Monitor. Comment: Patients taking aspirin may experience increased bruising or bleeding at biopsy and/or injection sites. Concomitant use of aspirin is not recommended. .

• azilsartan

  Monitor Closely (2)aspirin, azilsartan. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  aspirin decreases effects of azilsartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.

• baclofen

  Monitor Closely (2)baclofen and carisoprodol both increase sedation. Use Caution/Monitor.
  
  baclofen and codeine both increase sedation. Use Caution/Monitor.

• balsalazide

  Minor (1)aspirin will increase the level or effect of balsalazide by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• belladonna and opium

  Monitor Closely (2)codeine and belladonna and opium both increase sedation. Use Caution/Monitor.
  
  carisoprodol and belladonna and opium both increase sedation. Use Caution/Monitor.

• bemiparin

  Monitor Closely (1)bemiparin and aspirin both increase anticoagulation. Modify Therapy/Monitor Closely.

• benazepril

  Monitor Closely (1)benazepril, aspirin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly with high dose aspirin, in elderly or volume depleted individuals.Serious - Use Alternative (1)aspirin, benazepril. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Coadministration may result in a significant decrease in renal function. NSAIDs may diminish the antihypertensive effect of ACE inhibitors. The mechanism of these interactions is likely related to the ability of NSAIDs to reduce the synthesis of vasodilating renal prostaglandins.

• bendroflumethiazide

  Monitor Closely (1)aspirin increases and bendroflumethiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)bendroflumethiazide will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• benperidol

  Monitor Closely (2)codeine and benperidol both increase sedation. Use Caution/Monitor.
  
  carisoprodol and benperidol both increase sedation. Use Caution/Monitor.

• benzhydrocodone/acetaminophen

  Serious - Use Alternative (4)benzhydrocodone/acetaminophen and codeine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate
  
  benzhydrocodone/acetaminophen, codeine. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.
  
  benzhydrocodone/acetaminophen and carisoprodol both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate
  
  benzhydrocodone/acetaminophen, carisoprodol. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

• benzphetamine

  Monitor Closely (2)codeine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  carisoprodol increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• betaxolol

  Monitor Closely (2)aspirin decreases effects of betaxolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  betaxolol and aspirin both increase serum potassium. Use Caution/Monitor.

• betrixaban

  Monitor Closely (1)aspirin, betrixaban. Either increases levels of the other by anticoagulation. Use Caution/Monitor.

• bimatoprost

  Monitor Closely (1)bimatoprost, aspirin. unspecified interaction mechanism. Use Caution/Monitor. There are conflicting reports from studies of either increased or decreased IOP when ophthalmic prostaglandins are coadministered with NSAIDs (either systemic or ophthalmic).

• bismuth subsalicylate

  Minor (1)bismuth subsalicylate increases effects of aspirin by pharmacodynamic synergism. Minor/Significance Unknown.

• bisoprolol

  Monitor Closely (2)aspirin decreases effects of bisoprolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  bisoprolol and aspirin both increase serum potassium. Use Caution/Monitor.

• bivalirudin

  Monitor Closely (2)aspirin, bivalirudin. Either increases toxicity of the other by anticoagulation. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; monitor closely.
  
  bivalirudin and aspirin both increase anticoagulation. Modify Therapy/Monitor Closely.

• bremelanotide

  Serious - Use Alternative (1)bremelanotide will decrease the level or effect of codeine by Other (see comment). Avoid or Use Alternate Drug. Bremelanotide may slow gastric emptying and potentially reduces the rate and extent of absorption of concomitantly administered oral medications. Avoid use when taking any oral drug that is dependent on threshold concentrations for efficacy. Interactions listed are representative examples and do not include all possible clinical examples.

• brexanolone

  Monitor Closely (2)brexanolone, carisoprodol. Either increases toxicity of the other by sedation. Use Caution/Monitor.
  
  brexanolone, codeine. Either increases toxicity of the other by sedation. Use Caution/Monitor.

• brexpiprazole

  Monitor Closely (2)brexpiprazole and carisoprodol both increase sedation. Use Caution/Monitor.
  
  brexpiprazole and codeine both increase sedation. Use Caution/Monitor.

• brimonidine

  Monitor Closely (1)brimonidine and carisoprodol both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)brimonidine and codeine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequateMinor (1)brimonidine increases effects of codeine by pharmacodynamic synergism. Minor/Significance Unknown. Increased CNS depression.

• brinzolamide

  Monitor Closely (1)brinzolamide, aspirin. Either increases levels of the other by Other (see comment). Use Caution/Monitor. Comment: Carbonic anhydrase inhibitors (CAIs) and salicylates inhibit each other's renal tubular secretion, resulting in increased plasma levels. CAIs also shift salicylates from plasma to the CNS, leading to potential neurotoxicity.

• brivaracetam

  Monitor Closely (2)brivaracetam and carisoprodol both increase sedation. Use Caution/Monitor.
  
  brivaracetam and codeine both increase sedation. Use Caution/Monitor.

• brompheniramine

  Monitor Closely (2)brompheniramine and carisoprodol both increase sedation. Use Caution/Monitor.
  
  brompheniramine and codeine both increase sedation. Use Caution/Monitor.

• bumetanide

  Monitor Closely (2)aspirin decreases effects of bumetanide by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.
  
  aspirin increases and bumetanide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)aspirin, bumetanide. Other (see comment). Minor/Significance Unknown. Comment: Salicylates are less likely than other NSAIDs to interact w/bumetanide.

• buprenorphine

  Monitor Closely (2)buprenorphine and codeine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and buprenorphine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)buprenorphine, codeine. Other (see comment). Avoid or Use Alternate Drug. Comment: Mixed opiate agonist/antagonists usually produce additive sedation with narcotics; however, in narcotic addicted pts., the antagonist activity may provoke withdrawal Sx.

• buprenorphine buccal

  Monitor Closely (2)carisoprodol and buprenorphine buccal both increase sedation. Use Caution/Monitor.
  
  buprenorphine buccal and codeine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)buprenorphine buccal, codeine. Other (see comment). Avoid or Use Alternate Drug. Comment: Mixed opiate agonist/antagonists usually produce additive sedation with narcotics; however, in narcotic addicted pts., the antagonist activity may provoke withdrawal Sx.

• buprenorphine subdermal implant

  Serious - Use Alternative (2)buprenorphine subdermal implant and carisoprodol both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate
  
  buprenorphine subdermal implant and codeine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate

• buprenorphine, long-acting injection

  Monitor Closely (2)buprenorphine, long-acting injection increases effects of carisoprodol by Other (see comment). Modify Therapy/Monitor Closely. Comment: Buprenorphine may enhance the neuromuscular blocking action of skeletal muscle relaxants and increase risk for respiratory depression. Monitor for signs of respiratory depression that may be greater than otherwise expected and decrease muscle relaxant dosage as necessary.
  
  codeine increases toxicity of buprenorphine, long-acting injection by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of buprenorphine and benzodiazepines or other CNS depressants increases risk of adverse reactions including overdose, respiratory depression, and death. Cessation of benzodiazepines or other CNS depressants is preferred in most cases. In some cases, monitoring at a higher level of care for tapering CNS depressants may be appropriate. In others, gradually tapering a patient off of a prescribed benzodiazepine or other CNS depressant or decreasing to the lowest effective dose may be appropriate.

• bupropion

  Monitor Closely (1)bupropion will decrease the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents the conversion of codeine to its active metabolite morphine.

• butabarbital

  Monitor Closely (2)butabarbital and codeine both increase sedation. Use Caution/Monitor.
  
  butabarbital and carisoprodol both increase sedation. Use Caution/Monitor.

• butalbital

  Monitor Closely (2)butalbital and codeine both increase sedation. Use Caution/Monitor.
  
  butalbital and carisoprodol both increase sedation. Use Caution/Monitor.

• butorphanol

  Monitor Closely (2)butorphanol and codeine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and butorphanol both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)butorphanol, codeine. Other (see comment). Avoid or Use Alternate Drug. Comment: Mixed opiate agonist/antagonists usually produce additive sedation with narcotics; however, in narcotic addicted pts., the antagonist activity may provoke withdrawal Sx.

• caffeine

  Monitor Closely (1)codeine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• calcium carbonate

  Minor (1)calcium carbonate, aspirin. Mechanism: passive renal tubular reabsorption due to increased pH. Minor/Significance Unknown. Salicylate levels increased at moderate doses; salicylate levels decreased at large doses (d/t increased renal excretion of unchanged salicylic acid).

• calcium/magnesium/potassium/sodium oxybates

  Serious - Use Alternative (2)carisoprodol, calcium/magnesium/potassium/sodium oxybates. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.
  
  codeine, calcium/magnesium/potassium/sodium oxybates. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

• candesartan

  Monitor Closely (3)candesartan, aspirin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  aspirin decreases effects of candesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  candesartan and aspirin both increase serum potassium. Use Caution/Monitor.

• cannabidiol

  Monitor Closely (1)cannabidiol will increase the level or effect of carisoprodol by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Consider reducing the dose of sensitive CYP2C19 substrates, as clinically appropriate, when coadministered with cannabidiol.

• caplacizumab

  Serious - Use Alternative (1)caplacizumab, aspirin. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug.

• captopril

  Monitor Closely (1)captopril, aspirin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly with high dose aspirin, elderly or volume depleted individuals.Serious - Use Alternative (1)aspirin, captopril. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Coadministration may result in a significant decrease in renal function. NSAIDs may diminish the antihypertensive effect of ACE inhibitors. The mechanism of these interactions is likely related to the ability of NSAIDs to reduce the synthesis of vasodilating renal prostaglandins.

• carbenoxolone

  Monitor Closely (1)aspirin increases and carbenoxolone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• carbinoxamine

  Monitor Closely (2)carbinoxamine and codeine both increase sedation. Use Caution/Monitor.
  
  carbinoxamine and carisoprodol both increase sedation. Use Caution/Monitor.

• carisoprodol

  Monitor Closely (1)carisoprodol and codeine both increase sedation. Use Caution/Monitor.

• carvedilol

  Monitor Closely (2)aspirin decreases effects of carvedilol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  carvedilol and aspirin both increase serum potassium. Use Caution/Monitor.

• cefadroxil

  Minor (1)cefadroxil will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• cefamandole

  Minor (1)cefamandole will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• cefepime

  Minor (1)cefepime will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• cefixime

  Minor (1)cefixime will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• cefpirome

  Minor (1)cefpirome will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• cefprozil

  Minor (1)cefprozil will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• ceftazidime

  Minor (1)ceftazidime will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• ceftibuten

  Minor (1)ceftibuten will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• celecoxib

  Monitor Closely (3)aspirin and celecoxib both increase serum potassium. Use Caution/Monitor.
  
  celecoxib decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.
  
  aspirin and celecoxib both increase anticoagulation. Use Caution/Monitor.Minor (1)aspirin will increase the level or effect of celecoxib by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• celiprolol

  Monitor Closely (2)aspirin decreases effects of celiprolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  celiprolol and aspirin both increase serum potassium. Use Caution/Monitor.

• cenobamate

  Monitor Closely (3)cenobamate will increase the level or effect of carisoprodol by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Consider a dose reduction of CYP2C19 substrates, as clinically appropriate, when used concomitantly with cenobamate.
  
  cenobamate, carisoprodol. Either increases effects of the other by sedation. Use Caution/Monitor.
  
  cenobamate, codeine. Either increases effects of the other by sedation. Use Caution/Monitor.

• cephalexin

  Minor (1)cephalexin will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• ceritinib

  Minor (1)aspirin will decrease the level or effect of ceritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• chloral hydrate

  Monitor Closely (2)chloral hydrate and codeine both increase sedation. Use Caution/Monitor.
  
  chloral hydrate and carisoprodol both increase sedation. Use Caution/Monitor.

• chlordiazepoxide

  Monitor Closely (2)chlordiazepoxide and codeine both increase sedation. Use Caution/Monitor.
  
  chlordiazepoxide and carisoprodol both increase sedation. Use Caution/Monitor.

• chloroquine

  Monitor Closely (1)chloroquine will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• chlorothiazide

  Monitor Closely (1)aspirin increases and chlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)chlorothiazide will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• chlorpheniramine

  Monitor Closely (2)chlorpheniramine and codeine both increase sedation. Use Caution/Monitor.
  
  chlorpheniramine and carisoprodol both increase sedation. Use Caution/Monitor.

• chlorpromazine

  Monitor Closely (3)chlorpromazine will decrease the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine
  
  codeine and chlorpromazine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and chlorpromazine both increase sedation. Use Caution/Monitor.

• chlorpropamide

  Monitor Closely (1)aspirin increases effects of chlorpropamide by unknown mechanism. Use Caution/Monitor. Risk of hypoglycemia.Minor (2)aspirin will increase the level or effect of chlorpropamide by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
  
  aspirin increases effects of chlorpropamide by plasma protein binding competition. Minor/Significance Unknown. Large dose of salicylate.

• chlorthalidone

  Monitor Closely (1)aspirin increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)chlorthalidone will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• chlorzoxazone

  Monitor Closely (1)chlorzoxazone and codeine both increase sedation. Use Caution/Monitor.

• choline magnesium trisalicylate

  Monitor Closely (2)aspirin and choline magnesium trisalicylate both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and choline magnesium trisalicylate both increase serum potassium. Use Caution/Monitor.Minor (1)aspirin will increase the level or effect of choline magnesium trisalicylate by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• chromium

  Minor (1)aspirin increases levels of chromium by unspecified interaction mechanism. Minor/Significance Unknown.

• cilostazol

  Monitor Closely (1)aspirin, cilostazol. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; monitor closely.

• cimetidine

  Monitor Closely (1)cimetidine will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• cinacalcet

  Monitor Closely (1)cinacalcet decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• cinnamon

  Monitor Closely (1)aspirin and cinnamon both increase anticoagulation. Use Caution/Monitor.

• cinnarizine

  Monitor Closely (2)cinnarizine and codeine both increase sedation. Use Caution/Monitor.
  
  cinnarizine and carisoprodol both increase sedation. Use Caution/Monitor.

• ciprofloxacin

  Monitor Closely (1)aspirin decreases levels of ciprofloxacin by Other (see comment). Use Caution/Monitor. Comment: Buffered aspirin may decrease absorption of quinolones. Consider administering 2 hr before or 6 hr after, buffered aspirin administration.

• citalopram

  Monitor Closely (1)citalopram, aspirin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. If possible, avoid concurrent use.

• clemastine

  Monitor Closely (2)clemastine and carisoprodol both increase sedation. Use Caution/Monitor.
  
  clemastine and codeine both increase sedation. Use Caution/Monitor.

• clobazam

  Monitor Closely (3)carisoprodol, clobazam. Other (see comment). Use Caution/Monitor. Comment: Concomitant administration can increase the potential for CNS effects (e.g., increased sedation or respiratory depression).
  
  codeine, clobazam. Other (see comment). Use Caution/Monitor. Comment: Concomitant administration can increase the potential for CNS effects (e.g., increased sedation or respiratory depression).
  
  clobazam decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• clomipramine

  Monitor Closely (4)clomipramine, aspirin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. Clomipramine inhib. serotonin uptake by platelets.
  
  codeine and clomipramine both increase sedation. Use Caution/Monitor.
  
  clomipramine decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.
  
  carisoprodol and clomipramine both increase sedation. Use Caution/Monitor.

• clonazepam

  Monitor Closely (2)clonazepam and carisoprodol both increase sedation. Use Caution/Monitor.
  
  clonazepam and codeine both increase sedation. Use Caution/Monitor.

• clonidine

  Serious - Use Alternative (1)clonidine, codeine. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration enhances CNS depressant effects.

• clopidogrel

  Monitor Closely (1)aspirin, clopidogrel. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; monitor closely.

• clorazepate

  Monitor Closely (2)clorazepate and codeine both increase sedation. Use Caution/Monitor.
  
  clorazepate and carisoprodol both increase sedation. Use Caution/Monitor.

• clozapine

  Monitor Closely (3)codeine and clozapine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and clozapine both increase sedation. Use Caution/Monitor.
  
  clozapine decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• cocaine topical

  Monitor Closely (1)cocaine topical decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• codeine

  Monitor Closely (1)carisoprodol and codeine both increase sedation. Use Caution/Monitor.

• collagenase clostridium histolyticum

  Monitor Closely (1)aspirin increases toxicity of collagenase clostridium histolyticum by anticoagulation. Use Caution/Monitor. Collagenase clostridium histolyticum has high incidence of ecchymosis/contusion at injection site; avoid concomitant anticoagulants (except for low-dose aspirin, ie, up to 150 mg/day).

• cordyceps

  Monitor Closely (1)aspirin and cordyceps both increase anticoagulation. Use Caution/Monitor.

• cortisone

  Monitor Closely (1)aspirin, cortisone. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of GI ulceration.Minor (1)cortisone decreases levels of aspirin by increasing renal clearance. Minor/Significance Unknown.

• creatine

  Minor (1)creatine, aspirin. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. (Theoretical interaction) Combination may have additive nephrotoxic effects.

• cyanocobalamin

  Minor (1)aspirin decreases levels of cyanocobalamin by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• cyclizine

  Monitor Closely (2)cyclizine and carisoprodol both increase sedation. Use Caution/Monitor.
  
  cyclizine and codeine both increase sedation. Use Caution/Monitor.

• cyclobenzaprine

  Monitor Closely (2)cyclobenzaprine and codeine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and cyclobenzaprine both increase sedation. Use Caution/Monitor.

• cyclopenthiazide

  Monitor Closely (1)aspirin increases and cyclopenthiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)cyclopenthiazide will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• cyclophosphamide

  Minor (1)aspirin will decrease the level or effect of cyclophosphamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• cyproheptadine

  Monitor Closely (2)cyproheptadine and codeine both increase sedation. Use Caution/Monitor.
  
  cyproheptadine and carisoprodol both increase sedation. Use Caution/Monitor.

• dabigatran

  Monitor Closely (1)dabigatran and aspirin both increase anticoagulation. Modify Therapy/Monitor Closely. Both drugs have the potential to cause bleeding. The need for simultaneous use of low-dose aspirin (<100 mg/day) with anticoagulants are common for patients with cardiovascular disease, but may result in increased bleeding; monitor closely. Promptly evaluate any signs or symptoms of blood loss if treated concomitantly with low-dose aspirin. Avoid coadministration with chronic use of higher dose aspirin

• dacomitinib

  Serious - Use Alternative (1)dacomitinib will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. Avoid use with CYP2D6 substrates where minimal increases in concentration of the CYP2D6 substrate may lead to serious or life-threatening toxicities.

• dalteparin

  Monitor Closely (2)aspirin, dalteparin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; monitor closely.
  
  dalteparin and aspirin both increase anticoagulation. Modify Therapy/Monitor Closely.

• danshen

  Minor (1)aspirin and danshen both increase anticoagulation. Minor/Significance Unknown.

• dantrolene

  Monitor Closely (2)dantrolene and codeine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and dantrolene both increase sedation. Use Caution/Monitor.

• daridorexant

  Monitor Closely (2)codeine and daridorexant both increase sedation. Modify Therapy/Monitor Closely. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment.
  
  carisoprodol and daridorexant both increase sedation. Modify Therapy/Monitor Closely. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment.

• darifenacin

  Monitor Closely (1)darifenacin decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• deferasirox

  Monitor Closely (1)deferasirox, aspirin. Other (see comment). Use Caution/Monitor. Comment: Combination may increase GI bleeding, ulceration and irritation. Use with caution.

• defibrotide

  Monitor Closely (1)defibrotide increases effects of aspirin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Defibrotide may enhance effects of platelet inhibitors.

• deflazacort

  Monitor Closely (1)aspirin, deflazacort. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of GI ulceration.Minor (1)deflazacort decreases levels of aspirin by increasing renal clearance. Minor/Significance Unknown.

• desflurane

  Monitor Closely (1)desflurane and codeine both increase sedation. Use Caution/Monitor. Opioids may decrease MAC requirements, less inhalation anesthetic may be required.

• desipramine

  Monitor Closely (3)codeine and desipramine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and desipramine both increase sedation. Use Caution/Monitor.
  
  desipramine decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• desirudin

  Monitor Closely (1)aspirin, desirudin. Either increases levels of the other by pharmacodynamic synergism. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; monitor closely.

• desvenlafaxine

  Monitor Closely (1)desvenlafaxine will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Desvenlafaxine inhibits CYP2D6; with higher desvenlafaxine doses (ie, 400 mg) decrease the CYP2D6 substrate dose by up to 50%; no dosage adjustment needed with desvenlafaxine doses <100 mg

• deutetrabenazine

  Monitor Closely (1)codeine and deutetrabenazine both increase sedation. Use Caution/Monitor.

• devil's claw

  Minor (1)aspirin and devil's claw both increase anticoagulation. Minor/Significance Unknown.

• dexamethasone

  Monitor Closely (1)aspirin, dexamethasone. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of GI ulceration.Minor (1)dexamethasone decreases levels of aspirin by increasing renal clearance. Minor/Significance Unknown.

• dexchlorpheniramine

  Monitor Closely (2)dexchlorpheniramine and carisoprodol both increase sedation. Use Caution/Monitor.
  
  dexchlorpheniramine and codeine both increase sedation. Use Caution/Monitor.

• dexfenfluramine

  Monitor Closely (2)codeine increases and dexfenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  carisoprodol increases and dexfenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• dexmedetomidine

  Monitor Closely (2)dexmedetomidine and carisoprodol both increase sedation. Use Caution/Monitor.
  
  dexmedetomidine and codeine both increase sedation. Use Caution/Monitor.

• dexmethylphenidate

  Monitor Closely (1)codeine increases and dexmethylphenidate decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• dextroamphetamine

  Monitor Closely (1)codeine increases and dextroamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)dextroamphetamine increases effects of codeine by unspecified interaction mechanism. Minor/Significance Unknown.

• dextromoramide

  Monitor Closely (2)codeine and dextromoramide both increase sedation. Use Caution/Monitor.
  
  carisoprodol and dextromoramide both increase sedation. Use Caution/Monitor.

• diamorphine

  Monitor Closely (2)carisoprodol and diamorphine both increase sedation. Use Caution/Monitor.
  
  codeine and diamorphine both increase sedation. Use Caution/Monitor.

• diazepam

  Monitor Closely (2)diazepam and carisoprodol both increase sedation. Use Caution/Monitor.
  
  diazepam and codeine both increase sedation. Use Caution/Monitor.

• diazepam intranasal

  Monitor Closely (1)diazepam intranasal, carisoprodol. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration may potentiate the CNS-depressant effects of each drug.Serious - Use Alternative (1)diazepam intranasal, codeine. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

• dichlorphenamide

  Contraindicated (1)dichlorphenamide increases levels of aspirin by unknown mechanism. Contraindicated. Coadministration of dichlorphenamide with high-dose aspirin may increase salicylate levels. Anorexia, tachypnea, lethargy, and coma reported.

• diclofenac

  Monitor Closely (2)aspirin and diclofenac both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and diclofenac both increase serum potassium. Use Caution/Monitor.Minor (1)aspirin will increase the level or effect of diclofenac by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• diclofenac topical

  Minor (1)diclofenac topical, aspirin. Either increases effects of the other by pharmacodynamic synergism. Minor/Significance Unknown. Although low, there is systemic exposure to diclofenac topical; theoretically, concomitant administration with systemic NSAIDS or aspirin may result in increased NSAID adverse effects.

• dicloxacillin

  Monitor Closely (1)dicloxacillin, aspirin. Either increases levels of the other by plasma protein binding competition. Use Caution/Monitor.

• diethylpropion

  Monitor Closely (1)codeine increases and diethylpropion decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• difelikefalin

  Monitor Closely (2)difelikefalin and codeine both increase sedation. Use Caution/Monitor.
  
  difelikefalin and carisoprodol both increase sedation. Use Caution/Monitor.

• difenoxin hcl

  Monitor Closely (2)carisoprodol and difenoxin hcl both increase sedation. Use Caution/Monitor.
  
  codeine and difenoxin hcl both increase sedation. Use Caution/Monitor.

• diflunisal

  Monitor Closely (2)aspirin and diflunisal both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and diflunisal both increase serum potassium. Use Caution/Monitor.Minor (1)aspirin will increase the level or effect of diflunisal by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• digoxin

  Monitor Closely (1)aspirin and digoxin both increase serum potassium. Use Caution/Monitor.

• diltiazem

  Minor (1)diltiazem increases effects of aspirin by unknown mechanism. Minor/Significance Unknown. Enhanced antiplatelet activity.

• dimenhydrinate

  Monitor Closely (2)dimenhydrinate and carisoprodol both increase sedation. Use Caution/Monitor.
  
  dimenhydrinate and codeine both increase sedation. Use Caution/Monitor.

• diphenhydramine

  Monitor Closely (3)diphenhydramine decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.
  
  diphenhydramine and codeine both increase sedation. Use Caution/Monitor.
  
  diphenhydramine and carisoprodol both increase sedation. Use Caution/Monitor.

• diphenoxylate hcl

  Monitor Closely (2)codeine and diphenoxylate hcl both increase sedation. Use Caution/Monitor.
  
  carisoprodol and diphenoxylate hcl both increase sedation. Use Caution/Monitor.

• dipipanone

  Monitor Closely (2)codeine and dipipanone both increase sedation. Use Caution/Monitor.
  
  carisoprodol and dipipanone both increase sedation. Use Caution/Monitor.

• dipyridamole

  Monitor Closely (1)aspirin, dipyridamole. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; monitor closely.

• dobutamine

  Monitor Closely (2)codeine increases and dobutamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  aspirin increases and dobutamine decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• dong quai

  Monitor Closely (1)aspirin and dong quai both increase anticoagulation. Use Caution/Monitor.

• dopamine

  Monitor Closely (1)codeine increases and dopamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• dopexamine

  Monitor Closely (3)carisoprodol increases and dopexamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  aspirin increases and dopexamine decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  codeine increases and dopexamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• dosulepin

  Monitor Closely (2)codeine and dosulepin both increase sedation. Use Caution/Monitor.
  
  carisoprodol and dosulepin both increase sedation. Use Caution/Monitor.

• doxazosin

  Monitor Closely (1)aspirin decreases effects of doxazosin by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.

• doxepin

  Monitor Closely (2)codeine and doxepin both increase sedation. Use Caution/Monitor.
  
  carisoprodol and doxepin both increase sedation. Use Caution/Monitor.

• doxylamine

  Monitor Closely (2)doxylamine and codeine both increase sedation. Use Caution/Monitor.
  
  doxylamine and carisoprodol both increase sedation. Use Caution/Monitor.

• dronedarone

  Monitor Closely (1)dronedarone decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• droperidol

  Monitor Closely (2)codeine and droperidol both increase sedation. Use Caution/Monitor.
  
  carisoprodol and droperidol both increase sedation. Use Caution/Monitor.

• drospirenone

  Monitor Closely (1)drospirenone and aspirin both increase serum potassium. Modify Therapy/Monitor Closely.

• duloxetine

  Monitor Closely (2)duloxetine, aspirin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.
  
  duloxetine decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• edoxaban

  Monitor Closely (1)edoxaban, aspirin. Either increases toxicity of the other by anticoagulation. Modify Therapy/Monitor Closely. Both drugs have the potential to cause bleeding. The need for simultaneous use of low-dose aspirin (<100 mg/day) with anticoagulants are common for patients with cardiovascular disease, but may result in increased bleeding; monitor closely. Promptly evaluate any signs or symptoms of blood loss if treated concomitantly with low-dose aspirin. Avoid coadministration with chronic use of higher dose aspirin.

• elagolix

  Monitor Closely (1)elagolix will increase the level or effect of carisoprodol by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Elagolix is a weak CYP2C19 inhibitor. Caution with sensitive CYP2C19 substrates.

• eluxadoline

  Serious - Use Alternative (1)codeine, eluxadoline. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Avoid coadministration with other drugs that cause constipation. Increases risk for constipation related serious adverse reactions. .

• elvitegravir/cobicistat/emtricitabine/tenofovir DF

  Monitor Closely (2)elvitegravir/cobicistat/emtricitabine/tenofovir DF, aspirin. Either increases toxicity of the other by decreasing renal clearance. Modify Therapy/Monitor Closely. Toxicity may result from coadministration of emtricitabine and tenofovir with other drugs that are also primarily excreted by glomerular filtration and/or active tubular secretion including high-dose or multiple-dose NSAIDs; alternatives to NSAIDs should be considered.
  
  elvitegravir/cobicistat/emtricitabine/tenofovir DF increases levels of codeine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Cobicistat is a CYP2D6 inhibitor; caution with CYP2D6 substrates for which elevated plasma concentrations are associated with serious and/or life-threatening events.

• enalapril

  Monitor Closely (1)enalapril, aspirin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly with high dose aspirin, in elderly or volume depleted individuals.Serious - Use Alternative (1)aspirin, enalapril. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Coadministration may result in a significant decrease in renal function. NSAIDs may diminish the antihypertensive effect of ACE inhibitors. The mechanism of these interactions is likely related to the ability of NSAIDs to reduce the synthesis of vasodilating renal prostaglandins.

• enoxaparin

  Monitor Closely (2)enoxaparin and aspirin both increase anticoagulation. Use Caution/Monitor. Additive effects are intended when both drugs are prescribed as indicated for unstable angina, non-Q-wave MI, and STEMI
  
  aspirin, enoxaparin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; monitor closely.

• ephedrine

  Monitor Closely (2)aspirin increases and ephedrine decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  codeine increases and ephedrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• epinephrine

  Monitor Closely (2)aspirin increases and epinephrine decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  codeine increases and epinephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• epinephrine racemic

  Monitor Closely (2)codeine increases and epinephrine racemic decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  aspirin increases and epinephrine racemic decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• eplerenone

  Minor (1)aspirin decreases effects of eplerenone by pharmacodynamic antagonism. Minor/Significance Unknown. NSAIDs decrease prostaglandin synthesis.

• epoprostenol

  Monitor Closely (1)aspirin and epoprostenol both increase anticoagulation. Use Caution/Monitor.

• eprosartan

  Monitor Closely (3)aspirin decreases effects of eprosartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  eprosartan and aspirin both increase serum potassium. Use Caution/Monitor.
  
  eprosartan, aspirin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.

• eptifibatide

  Monitor Closely (1)aspirin, eptifibatide. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; monitor closely.

• escitalopram

  Monitor Closely (1)escitalopram, aspirin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• esketamine intranasal

  Monitor Closely (2)esketamine intranasal, codeine. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely.
  
  esketamine intranasal, carisoprodol. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely.

• eslicarbazepine acetate

  Monitor Closely (1)eslicarbazepine acetate will increase the level or effect of carisoprodol by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.

• esmolol

  Monitor Closely (2)aspirin decreases effects of esmolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  esmolol and aspirin both increase serum potassium. Use Caution/Monitor.

• estazolam

  Monitor Closely (2)estazolam and codeine both increase sedation. Use Caution/Monitor.
  
  estazolam and carisoprodol both increase sedation. Use Caution/Monitor.

• ethacrynic acid

  Monitor Closely (1)aspirin increases and ethacrynic acid decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• ethanol

  Monitor Closely (2)carisoprodol and ethanol both increase sedation. Use Caution/Monitor.
  
  codeine and ethanol both increase sedation. Use Caution/Monitor.Minor (1)ethanol increases toxicity of aspirin by pharmacodynamic synergism. Minor/Significance Unknown. Increased risk of GI bleeding.

• etodolac

  Monitor Closely (2)aspirin and etodolac both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and etodolac both increase serum potassium. Use Caution/Monitor.Minor (1)aspirin will increase the level or effect of etodolac by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• etomidate

  Monitor Closely (2)etomidate and codeine both increase sedation. Use Caution/Monitor.
  
  etomidate and carisoprodol both increase sedation. Use Caution/Monitor.

• eucalyptus

  Minor (2)codeine and eucalyptus both increase sedation. Minor/Significance Unknown.
  
  carisoprodol and eucalyptus both increase sedation. Minor/Significance Unknown.

• fedratinib

  Monitor Closely (2)fedratinib will increase the level or effect of carisoprodol by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP2C19 substrates as necessary.
  
  fedratinib will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP2D6 substrates as necessary.

• fenbufen

  Monitor Closely (2)aspirin and fenbufen both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and fenbufen both increase serum potassium. Use Caution/Monitor.Minor (1)aspirin will increase the level or effect of fenbufen by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• fenfluramine

  Monitor Closely (2)carisoprodol increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  codeine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• fennel

  Monitor Closely (1)aspirin and fennel both increase anticoagulation. Use Caution/Monitor.

• fenoprofen

  Monitor Closely (2)aspirin and fenoprofen both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and fenoprofen both increase serum potassium. Use Caution/Monitor.Minor (1)aspirin will increase the level or effect of fenoprofen by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• fentanyl

  Serious - Use Alternative (1)fentanyl, codeine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration with other CNS depressants, such as skeletal muscle relaxants, may cause respiratory depression, hypotension, profound sedation, coma, and/or death. Consider dose reduction of either or both agents to avoid serious adverse effects. Monitor for hypotension, respiratory depression, and profound sedation.

• fentanyl intranasal

  Serious - Use Alternative (1)fentanyl intranasal, codeine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration with other CNS depressants, such as skeletal muscle relaxants, may cause respiratory depression, hypotension, profound sedation, coma, and/or death. Consider dose reduction of either or both agents to avoid serious adverse effects. Monitor for hypotension, respiratory depression, and profound sedation.

• fentanyl transdermal

  Serious - Use Alternative (1)fentanyl transdermal, codeine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration with other CNS depressants, such as skeletal muscle relaxants, may cause respiratory depression, hypotension, profound sedation, coma, and/or death. Consider dose reduction of either or both agents to avoid serious adverse effects. Monitor for hypotension, respiratory depression, and profound sedation.

• fentanyl transmucosal

  Serious - Use Alternative (1)fentanyl transmucosal, codeine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration with other CNS depressants, such as skeletal muscle relaxants, may cause respiratory depression, hypotension, profound sedation, coma, and/or death. Consider dose reduction of either or both agents to avoid serious adverse effects. Monitor for hypotension, respiratory depression, and profound sedation.

• feverfew

  Monitor Closely (1)aspirin and feverfew both increase anticoagulation. Use Caution/Monitor.Minor (1)aspirin decreases effects of feverfew by pharmacodynamic antagonism. Minor/Significance Unknown.

• fexinidazole

  Monitor Closely (1)fexinidazole will increase the level or effect of carisoprodol by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.

• fish oil

  Monitor Closely (1)fish oil, aspirin. Other (see comment). Use Caution/Monitor. Comment: Patients taking fish oil and an anticoagulant or other drug affecting coagulation should be monitored periodically due to potential increased risk of bleeding. .

• fish oil triglycerides

  Monitor Closely (1)fish oil triglycerides will increase the level or effect of aspirin by anticoagulation. Use Caution/Monitor. Prolonged bleeding reported in patients taking antiplatelet agents or anticoagulants and oral omega-3 fatty acids. Periodically monitor bleeding time in patients receiving fish oil triglycerides and concomitant antiplatelet agents or anticoagulants.

• flibanserin

  Monitor Closely (1)codeine and flibanserin both increase sedation. Modify Therapy/Monitor Closely. Risk for sedation increased if flibanserin is coadministration with other CNS depressants.

• fludrocortisone

  Monitor Closely (1)aspirin, fludrocortisone. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of GI ulceration.Minor (1)fludrocortisone decreases levels of aspirin by increasing renal clearance. Minor/Significance Unknown.

• fluoxetine

  Monitor Closely (2)fluoxetine, aspirin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.
  
  fluoxetine will decrease the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphineMinor (1)fluoxetine decreases effects of codeine by decreasing metabolism. Minor/Significance Unknown. Decreased conversion of codeine to active metabolite morphine.

• fluphenazine

  Monitor Closely (2)carisoprodol and fluphenazine both increase sedation. Use Caution/Monitor.
  
  codeine and fluphenazine both increase sedation. Use Caution/Monitor.

• flurazepam

  Monitor Closely (2)flurazepam and codeine both increase sedation. Use Caution/Monitor.
  
  flurazepam and carisoprodol both increase sedation. Use Caution/Monitor.

• flurbiprofen

  Monitor Closely (2)aspirin and flurbiprofen both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and flurbiprofen both increase serum potassium. Use Caution/Monitor.Minor (1)aspirin will increase the level or effect of flurbiprofen by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• fluvoxamine

  Monitor Closely (1)fluvoxamine, aspirin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding SSRIs inhib. serotonin uptake by platelets.

• folic acid

  Minor (1)aspirin decreases levels of folic acid by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• fondaparinux

  Monitor Closely (1)fondaparinux and aspirin both increase anticoagulation. Modify Therapy/Monitor Closely.

• formoterol

  Monitor Closely (2)codeine increases and formoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  aspirin increases and formoterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• forskolin

  Monitor Closely (1)aspirin and forskolin both increase anticoagulation. Use Caution/Monitor.

• fosinopril

  Monitor Closely (1)fosinopril, aspirin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly with high dose aspirin, in elderly or volume depleted individuals.Serious - Use Alternative (1)aspirin, fosinopril. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Coadministration may result in a significant decrease in renal function. NSAIDs may diminish the antihypertensive effect of ACE inhibitors. The mechanism of these interactions is likely related to the ability of NSAIDs to reduce the synthesis of vasodilating renal prostaglandins.

• furosemide

  Monitor Closely (1)aspirin increases and furosemide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)aspirin decreases effects of furosemide by pharmacodynamic antagonism. Minor/Significance Unknown. NSAIDs decrease prostaglandin synthesis.

• gabapentin

  Monitor Closely (1)gabapentin, codeine. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of CNS depressants can result in serious, life-threatening, and fatal respiratory depression. Use lowest dose possible and monitor for respiratory depression and sedation.

• gabapentin enacarbil

  Monitor Closely (1)gabapentin enacarbil, codeine. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of CNS depressants can result in serious, life-threatening, and fatal respiratory depression. Use lowest dose possible and monitor for respiratory depression and sedation.

• ganaxolone

  Monitor Closely (2)codeine and ganaxolone both increase sedation. Use Caution/Monitor.
  
  carisoprodol and ganaxolone both increase sedation. Use Caution/Monitor.

• ganciclovir

  Minor (1)aspirin will increase the level or effect of ganciclovir by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• garlic

  Monitor Closely (1)aspirin and garlic both increase anticoagulation. Use Caution/Monitor.

• gentamicin

  Monitor Closely (1)aspirin increases and gentamicin decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)aspirin increases levels of gentamicin by decreasing renal clearance. Minor/Significance Unknown. Interaction mainly occurs in preterm infants.

• ginger

  Monitor Closely (1)aspirin and ginger both increase anticoagulation. Use Caution/Monitor.

• ginkgo biloba

  Monitor Closely (1)aspirin and ginkgo biloba both increase anticoagulation. Use Caution/Monitor.

• givosiran

  Serious - Use Alternative (1)givosiran will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sensitive CYP2D6 substrates with givosiran. If unavoidable, decrease the CYP2D6 substrate dosage in accordance with approved product labeling.

• glimepiride

  Monitor Closely (1)aspirin increases effects of glimepiride by unknown mechanism. Use Caution/Monitor. Risk of hypoglycemia.Minor (1)aspirin increases effects of glimepiride by plasma protein binding competition. Minor/Significance Unknown. Large dose of salicylate.

• glipizide

  Monitor Closely (1)aspirin increases effects of glipizide by unknown mechanism. Use Caution/Monitor. Risk of hypoglycemia.Minor (1)aspirin increases effects of glipizide by plasma protein binding competition. Minor/Significance Unknown. Large dose of salicylate.

• glyburide

  Monitor Closely (1)aspirin increases effects of glyburide by unknown mechanism. Use Caution/Monitor. Risk of hypoglycemia.Minor (1)aspirin increases effects of glyburide by plasma protein binding competition. Minor/Significance Unknown. Large dose of salicylate.

• green tea

  Monitor Closely (1)green tea increases effects of aspirin by pharmacodynamic synergism. Use Caution/Monitor. (Theoretical, due to caffeine content). Combination may increase risk of bleeding.

• griseofulvin

  Monitor Closely (1)griseofulvin decreases levels of aspirin by unknown mechanism. Use Caution/Monitor.

• haloperidol

  Monitor Closely (3)codeine and haloperidol both increase sedation. Use Caution/Monitor.
  
  carisoprodol and haloperidol both increase sedation. Use Caution/Monitor.
  
  haloperidol decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• heparin

  Monitor Closely (2)aspirin, heparin. Either increases toxicity of the other by anticoagulation. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; monitor closely.
  
  heparin and aspirin both increase anticoagulation. Modify Therapy/Monitor Closely.

• horse chestnut seed

  Monitor Closely (1)aspirin and horse chestnut seed both increase anticoagulation. Use Caution/Monitor.

• hyaluronidase

  Monitor Closely (1)aspirin decreases effects of hyaluronidase by Other (see comment). Use Caution/Monitor. Comment: Salicylates, when given in large systemic doses, may render tissues partially resistant to the action of hyaluronidase. Patients may require larger amounts of hyaluronidase for equivalent dispersing effect.

• hydralazine

  Monitor Closely (1)aspirin decreases effects of hydralazine by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.

• hydrochlorothiazide

  Monitor Closely (1)aspirin increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)hydrochlorothiazide will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• hydrocodone

  Serious - Use Alternative (2)hydrocodone, codeine. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.
  
  hydrocodone, carisoprodol. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

• hydrocortisone

  Monitor Closely (1)aspirin, hydrocortisone. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of GI ulceration.Minor (1)hydrocortisone decreases levels of aspirin by increasing renal clearance. Minor/Significance Unknown.

• hydromorphone

  Monitor Closely (2)carisoprodol and hydromorphone both increase sedation. Use Caution/Monitor.
  
  codeine and hydromorphone both increase sedation. Use Caution/Monitor.

• hydroxyzine

  Monitor Closely (2)hydroxyzine and codeine both increase sedation. Use Caution/Monitor.
  
  hydroxyzine and carisoprodol both increase sedation. Use Caution/Monitor.

• ibrutinib

  Monitor Closely (1)ibrutinib will increase the level or effect of aspirin by anticoagulation. Use Caution/Monitor. Ibrutinib may increase the risk of hemorrhage in patients receiving antiplatelet or anticoagulant therapies and monitor for signs of bleeding.

• ibuprofen

  Monitor Closely (2)aspirin and ibuprofen both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and ibuprofen both increase serum potassium. Use Caution/Monitor.Serious - Use Alternative (2)ibuprofen increases toxicity of aspirin by anticoagulation. Avoid or Use Alternate Drug. increases risk of bleeding.
  
  ibuprofen decreases effects of aspirin by Other (see comment). Avoid or Use Alternate Drug. Comment: Ibuprofen decreases the antiplatelet effects of low-dose aspirin by blocking the active site of platelet cyclooxygenase. Administer ibuprofen 8 h before aspirin or at least 2-4 h after aspirin. The effect of other NSAIDs on aspirin is not established.Minor (1)aspirin will increase the level or effect of ibuprofen by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• ibuprofen IV

  Monitor Closely (3)aspirin will increase the level or effect of ibuprofen IV by acidic (anionic) drug competition for renal tubular clearance. Modify Therapy/Monitor Closely.
  
  aspirin and ibuprofen IV both increase anticoagulation. Modify Therapy/Monitor Closely.
  
  aspirin and ibuprofen IV both increase serum potassium. Use Caution/Monitor.Serious - Use Alternative (2)ibuprofen IV increases toxicity of aspirin by anticoagulation. Avoid or Use Alternate Drug. increases risk of bleeding.
  
  ibuprofen IV decreases effects of aspirin by Other (see comment). Avoid or Use Alternate Drug. Comment: Ibuprofen decreases the antiplatelet effects of low-dose aspirin by blocking the active site of platelet cyclooxygenase. Administer ibuprofen 8 h before aspirin or at least 2-4 h after aspirin. The effect of other NSAIDs on aspirin is not established.

• icosapent

  Monitor Closely (1)icosapent, aspirin. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Icosapent may prolong bleeding time; monitor periodically if coadministered with other drugs that affect bleeding.

• iloperidone

  Monitor Closely (2)codeine and iloperidone both increase sedation. Use Caution/Monitor.
  
  carisoprodol and iloperidone both increase sedation. Use Caution/Monitor.

• imatinib

  Monitor Closely (1)imatinib, aspirin. Either increases toxicity of the other by Other (see comment). Modify Therapy/Monitor Closely. Comment: Imatinib may cause thrombocytopenia; bleeding risk increased when imatinib is coadministered with anticoagulants, NSAIDs, platelet inhibitors, and thrombolytic agents.Minor (2)imatinib decreases effects of codeine by decreasing metabolism. Minor/Significance Unknown. Decreased conversion of codeine to active metabolite morphine.
  
  imatinib will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• imidapril

  Minor (1)aspirin decreases effects of imidapril by pharmacodynamic antagonism. Minor/Significance Unknown. NSAIDs decrease prostaglandin synthesis.

• imipramine

  Monitor Closely (3)codeine and imipramine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and imipramine both increase sedation. Use Caution/Monitor.
  
  imipramine decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• incobotulinumtoxinA

  Monitor Closely (1)carisoprodol, incobotulinumtoxinA. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Muscle relaxants may enhance botulinum toxin effects. Closely monitor for increased neuromuscular blockade.

• indapamide

  Monitor Closely (1)aspirin increases and indapamide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)indapamide will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• indomethacin

  Monitor Closely (2)aspirin and indomethacin both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and indomethacin both increase serum potassium. Use Caution/Monitor.Minor (1)aspirin will increase the level or effect of indomethacin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• insulin aspart

  Monitor Closely (1)aspirin increases effects of insulin aspart by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of insulin with high doses of salicylates (3 g/day or more) may increase risk for hypoglycemia. Insulin dose adjustment and increased frequency of glucose monitoring may be required.

• insulin aspart protamine/insulin aspart

  Monitor Closely (1)aspirin increases effects of insulin aspart protamine/insulin aspart by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of insulin with high doses of salicylates (3 g/day or more) may increase risk for hypoglycemia. Insulin dose adjustment and increased frequency of glucose monitoring may be required.

• insulin degludec

  Monitor Closely (1)aspirin increases effects of insulin degludec by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of insulin with high doses of salicylates (3 g/day or more) may increase risk for hypoglycemia. Insulin dose adjustment and increased frequency of glucose monitoring may be required.

• insulin degludec/insulin aspart

  Monitor Closely (1)aspirin, insulin degludec/insulin aspart. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Both drugs decrease blood glucose.

• insulin detemir

  Monitor Closely (1)aspirin increases effects of insulin detemir by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of insulin with high doses of salicylates (3 g/day or more) may increase risk for hypoglycemia. Insulin dose adjustment and increased frequency of glucose monitoring may be required.

• insulin glargine

  Monitor Closely (1)aspirin increases effects of insulin glargine by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of insulin with high doses of salicylates (3 g/day or more) may increase risk for hypoglycemia. Insulin dose adjustment and increased frequency of glucose monitoring may be required.

• insulin glulisine

  Monitor Closely (1)aspirin increases effects of insulin glulisine by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of insulin with high doses of salicylates (3 g/day or more) may increase risk for hypoglycemia. Insulin dose adjustment and increased frequency of glucose monitoring may be required.

• insulin inhaled

  Monitor Closely (1)aspirin increases effects of insulin inhaled by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of insulin with high doses of salicylates (3 g/day or more) may increase risk for hypoglycemia. Insulin dose adjustment and increased frequency of glucose monitoring may be required.

• insulin isophane human/insulin regular human

  Monitor Closely (1)aspirin increases effects of insulin isophane human/insulin regular human by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of insulin with high doses of salicylates (3 g/day or more) may increase risk for hypoglycemia. Insulin dose adjustment and increased frequency of glucose monitoring may be required.

• insulin lispro

  Monitor Closely (1)aspirin increases effects of insulin lispro by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of insulin with high doses of salicylates (3 g/day or more) may increase risk for hypoglycemia. Insulin dose adjustment and increased frequency of glucose monitoring may be required.

• insulin lispro protamine/insulin lispro

  Monitor Closely (1)aspirin increases effects of insulin lispro protamine/insulin lispro by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of insulin with high doses of salicylates (3 g/day or more) may increase risk for hypoglycemia. Insulin dose adjustment and increased frequency of glucose monitoring may be required.

• insulin NPH

  Monitor Closely (1)aspirin increases effects of insulin NPH by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of insulin with high doses of salicylates (3 g/day or more) may increase risk for hypoglycemia. Insulin dose adjustment and increased frequency of glucose monitoring may be required.

• insulin regular human

  Monitor Closely (1)aspirin increases effects of insulin regular human by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of insulin with high doses of salicylates (3 g/day or more) may increase risk for hypoglycemia. Insulin dose adjustment and increased frequency of glucose monitoring may be required.

• irbesartan

  Monitor Closely (3)irbesartan, aspirin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  aspirin decreases effects of irbesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  irbesartan and aspirin both increase serum potassium. Use Caution/Monitor.

• isocarboxazid

  Serious - Use Alternative (1)isocarboxazid increases toxicity of codeine by unknown mechanism. Avoid or Use Alternate Drug. Risk of hypotension, hyperpyrexia, somnolence, or death; separate by 14 d.

• isoniazid

  Monitor Closely (1)isoniazid decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• isoproterenol

  Monitor Closely (2)codeine increases and isoproterenol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  aspirin increases and isoproterenol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• ketamine

  Monitor Closely (2)ketamine and codeine both increase sedation. Use Caution/Monitor.
  
  ketamine and carisoprodol both increase sedation. Use Caution/Monitor.

• ketoconazole

  Monitor Closely (1)ketoconazole decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• ketoprofen

  Monitor Closely (2)aspirin and ketoprofen both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and ketoprofen both increase serum potassium. Use Caution/Monitor.Minor (1)aspirin will increase the level or effect of ketoprofen by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• ketorolac

  Monitor Closely (2)aspirin and ketorolac both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and ketorolac both increase serum potassium. Use Caution/Monitor.Serious - Use Alternative (1)aspirin, ketorolac. Either increases toxicity of the other by pharmacodynamic synergism. Contraindicated.Minor (1)aspirin will increase the level or effect of ketorolac by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• ketorolac intranasal

  Monitor Closely (2)aspirin and ketorolac intranasal both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and ketorolac intranasal both increase serum potassium. Use Caution/Monitor.Serious - Use Alternative (1)aspirin, ketorolac intranasal. Either increases toxicity of the other by pharmacodynamic synergism. Contraindicated.Minor (1)aspirin will increase the level or effect of ketorolac intranasal by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• ketotifen, ophthalmic

  Monitor Closely (2)codeine and ketotifen, ophthalmic both increase sedation. Use Caution/Monitor.
  
  carisoprodol and ketotifen, ophthalmic both increase sedation. Use Caution/Monitor.

• L-methylfolate

  Minor (1)aspirin decreases levels of L-methylfolate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• labetalol

  Monitor Closely (2)aspirin decreases effects of labetalol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  labetalol and aspirin both increase serum potassium. Use Caution/Monitor.

• larotrectinib

  Minor (1)aspirin will decrease the level or effect of larotrectinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• lasmiditan

  Monitor Closely (2)lasmiditan, codeine. Either increases effects of the other by sedation. Use Caution/Monitor. Coadministration of lasmiditan and other CNS depressant drugs, including alcohol have not been evaluated in clinical studies. Lasmiditan may cause sedation, as well as other cognitive and/or neuropsychiatric adverse reactions.
  
  lasmiditan, carisoprodol. Either increases effects of the other by sedation. Use Caution/Monitor. Coadministration of lasmiditan and other CNS depressant drugs, including alcohol have not been evaluated in clinical studies. Lasmiditan may cause sedation, as well as other cognitive and/or neuropsychiatric adverse reactions.

• latanoprost

  Monitor Closely (1)latanoprost, aspirin. unspecified interaction mechanism. Use Caution/Monitor. There are conflicting reports from studies of either increased or decreased IOP when ophthalmic prostaglandins are coadministered with NSAIDs (either systemic or ophthalmic).

• latanoprostene bunod ophthalmic

  Monitor Closely (1)latanoprostene bunod ophthalmic, aspirin. unspecified interaction mechanism. Use Caution/Monitor. There are conflicting reports from studies of either increased or decreased IOP when ophthalmic prostaglandins are coadministered with NSAIDs (either systemic or ophthalmic).

• lemborexant

  Monitor Closely (2)lemborexant, codeine. Either increases effects of the other by sedation. Modify Therapy/Monitor Closely. Dosage adjustment may be necessary if lemborexant is coadministered with other CNS depressants because of potentially additive effects.
  
  lemborexant, carisoprodol. Either increases effects of the other by sedation. Modify Therapy/Monitor Closely. Dosage adjustment may be necessary if lemborexant is coadministered with other CNS depressants because of potentially additive effects.

• lesinurad

  Serious - Use Alternative (1)aspirin decreases effects of lesinurad by unspecified interaction mechanism. Avoid or Use Alternate Drug. Aspirin at doses >325 mg/day may decrease lesinurad efficacy. Aspirin doses 325 mg/day or less (ie, for cardiovascular event prophylaxis) does not decrease lesinurad efficacy and can be coadministered.

• letermovir

  Monitor Closely (1)letermovir increases levels of codeine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• levalbuterol

  Monitor Closely (2)aspirin increases and levalbuterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  codeine increases and levalbuterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• levoketoconazole

  Monitor Closely (1)levoketoconazole decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.Minor (1)aspirin will decrease the level or effect of levoketoconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• levomilnacipran

  Monitor Closely (1)levomilnacipran, aspirin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. SNRIs may further impair platelet activity in patients taking antiplatelet or anticoagulant drugs.

• levorphanol

  Monitor Closely (2)codeine and levorphanol both increase sedation. Use Caution/Monitor.
  
  carisoprodol and levorphanol both increase sedation. Use Caution/Monitor.

• lidocaine

  Minor (1)lidocaine increases toxicity of codeine by pharmacodynamic synergism. Minor/Significance Unknown. Risk of increased CNS depression.

• linezolid

  Serious - Use Alternative (1)linezolid increases toxicity of codeine by unknown mechanism. Avoid or Use Alternate Drug. Risk of hypotension, hyperpyrexia, somnolence, or death; separate by 14 d.

• lisdexamfetamine

  Monitor Closely (1)codeine increases and lisdexamfetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• lisinopril

  Monitor Closely (1)lisinopril, aspirin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly with high dose aspirin, in elderly or volume depleted individuals.Serious - Use Alternative (1)aspirin, lisinopril. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Coadministration may result in a significant decrease in renal function. NSAIDs may diminish the antihypertensive effect of ACE inhibitors. The mechanism of these interactions is likely related to the ability of NSAIDs to reduce the synthesis of vasodilating renal prostaglandins.

• lithium

  Monitor Closely (1)aspirin increases levels of lithium by decreasing renal clearance. Use Caution/Monitor.

• lofepramine

  Monitor Closely (2)carisoprodol and lofepramine both increase sedation. Use Caution/Monitor.
  
  codeine and lofepramine both increase sedation. Use Caution/Monitor.

• lofexidine

  Monitor Closely (2)codeine and lofexidine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and lofexidine both increase sedation. Use Caution/Monitor.

• lonafarnib

  Serious - Use Alternative (1)lonafarnib will increase the level or effect of carisoprodol by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug. Lonafarnib may increase the AUC and peak concentration of CYP2C19 substrates. If coadministration unavoidable, monitor for adverse reactions and reduce the CYP2C19 substrate dose in accordance with its approved product labeling.

• lopinavir

  Monitor Closely (1)lopinavir decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• loprazolam

  Monitor Closely (2)loprazolam and codeine both increase sedation. Use Caution/Monitor.
  
  loprazolam and carisoprodol both increase sedation. Use Caution/Monitor.

• lorazepam

  Monitor Closely (2)lorazepam and carisoprodol both increase sedation. Use Caution/Monitor.
  
  lorazepam and codeine both increase sedation. Use Caution/Monitor.

• lorcaserin

  Monitor Closely (1)lorcaserin will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• lormetazepam

  Monitor Closely (2)lormetazepam and codeine both increase sedation. Use Caution/Monitor.
  
  lormetazepam and carisoprodol both increase sedation. Use Caution/Monitor.

• lornoxicam

  Monitor Closely (2)aspirin and lornoxicam both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and lornoxicam both increase serum potassium. Use Caution/Monitor.Minor (1)aspirin will increase the level or effect of lornoxicam by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• losartan

  Monitor Closely (3)losartan, aspirin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  aspirin decreases effects of losartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  losartan and aspirin both increase serum potassium. Use Caution/Monitor.

• loxapine

  Monitor Closely (2)codeine and loxapine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and loxapine both increase sedation. Use Caution/Monitor.

• loxapine inhaled

  Monitor Closely (2)codeine and loxapine inhaled both increase sedation. Use Caution/Monitor.
  
  carisoprodol and loxapine inhaled both increase sedation. Use Caution/Monitor.

• lumacaftor/ivacaftor

  Monitor Closely (1)lumacaftor/ivacaftor, carisoprodol. affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. In vitro studies suggest that lumacaftor may induce and ivacaftor may inhibit CYP2C19 substrates. .

• lumefantrine

  Monitor Closely (1)lumefantrine will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

• lurasidone

  Monitor Closely (2)lurasidone, carisoprodol. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Potential for increased CNS depressant effects when used concurrently; monitor for increased adverse effects and toxicity.
  
  lurasidone, codeine. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Potential for increased CNS depressant effects when used concurrently; monitor for increased adverse effects and toxicity.

• macimorelin

  Serious - Use Alternative (1)aspirin, macimorelin. unspecified interaction mechanism. Avoid or Use Alternate Drug. Drugs that directly affect the pituitary secretion of growth hormone (GH) may impact the accuracy of the macimorelin diagnostic test. Allow sufficient washout time of drugs affecting GH release before administering macimorelin. .

• maprotiline

  Monitor Closely (2)carisoprodol and maprotiline both increase sedation. Use Caution/Monitor.
  
  codeine and maprotiline both increase sedation. Use Caution/Monitor.

• maraviroc

  Minor (1)maraviroc will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• marijuana

  Monitor Closely (2)carisoprodol and marijuana both increase sedation. Use Caution/Monitor.
  
  codeine and marijuana both increase sedation. Use Caution/Monitor.Minor (1)marijuana will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• measles, mumps, rubella and varicella vaccine, live

  Serious - Use Alternative (1)aspirin, measles, mumps, rubella and varicella vaccine, live. Mechanism: unspecified interaction mechanism. Avoid or Use Alternate Drug. Risk of Reye's Syndrome with combination; avoid salicylate use for 6 wks after vaccination.

• meclofenamate

  Monitor Closely (2)aspirin and meclofenamate both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and meclofenamate both increase serum potassium. Use Caution/Monitor.Minor (1)aspirin will increase the level or effect of meclofenamate by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• mefenamic acid

  Monitor Closely (2)aspirin and mefenamic acid both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and mefenamic acid both increase serum potassium. Use Caution/Monitor.Minor (1)aspirin will increase the level or effect of mefenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• melatonin

  Monitor Closely (3)carisoprodol and melatonin both increase sedation. Use Caution/Monitor.
  
  melatonin increases effects of aspirin by anticoagulation. Use Caution/Monitor. Melatonin may decrease prothrombin time.
  
  codeine and melatonin both increase sedation. Use Caution/Monitor.

• meloxicam

  Monitor Closely (2)aspirin and meloxicam both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and meloxicam both increase serum potassium. Use Caution/Monitor.Minor (1)aspirin will increase the level or effect of meloxicam by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• meperidine

  Monitor Closely (2)codeine and meperidine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and meperidine both increase sedation. Use Caution/Monitor.

• meprobamate

  Monitor Closely (2)codeine and meprobamate both increase sedation. Use Caution/Monitor.
  
  carisoprodol and meprobamate both increase sedation. Use Caution/Monitor.

• mesalamine

  Monitor Closely (1)mesalamine, aspirin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Additive nephrotoxicity.Minor (1)aspirin will increase the level or effect of mesalamine by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• metaproterenol

  Monitor Closely (2)aspirin increases and metaproterenol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  codeine increases and metaproterenol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• metaxalone

  Monitor Closely (2)carisoprodol and metaxalone both increase sedation. Use Caution/Monitor.
  
  metaxalone and codeine both increase sedation. Use Caution/Monitor.

• methadone

  Monitor Closely (2)codeine and methadone both increase sedation. Use Caution/Monitor.
  
  carisoprodol and methadone both increase sedation. Use Caution/Monitor.

• methamphetamine

  Monitor Closely (1)codeine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• methazolamide

  Monitor Closely (1)methazolamide, aspirin. Either increases levels of the other by Other (see comment). Use Caution/Monitor. Comment: Carbonic anhydrase inhibitors (CAIs) and salicylates inhibit each other's renal tubular secretion, resulting in increased plasma levels. CAIs also shift salicylates from plasma to the CNS, leading to potential neurotoxicity.

• methocarbamol

  Monitor Closely (2)carisoprodol and methocarbamol both increase sedation. Use Caution/Monitor.
  
  methocarbamol and codeine both increase sedation. Use Caution/Monitor.

• methotrexate

  Serious - Use Alternative (1)aspirin increases levels of methotrexate by decreasing renal clearance. Avoid or Use Alternate Drug. Caution should be exercised when salicylates are given in combination with methotrexate. Risk for drug interactions with methotrexate is greatest during high-dose methotrexate therapy, it has been recommended that any of these drugs be used cautiously with methotrexate even when methotrexate is used in low doses.

• methyclothiazide

  Monitor Closely (1)aspirin increases and methyclothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor. .Minor (1)methyclothiazide will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• methylene blue

  Serious - Use Alternative (1)methylene blue and codeine both increase serotonin levels. Avoid or Use Alternate Drug. If drug combination must be administered, monitor for evidence of serotonergic or opioid-related toxicities

• methylenedioxymethamphetamine

  Monitor Closely (2)codeine increases and methylenedioxymethamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  carisoprodol increases and methylenedioxymethamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• methylprednisolone

  Monitor Closely (1)aspirin, methylprednisolone. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of GI ulceration.Minor (1)methylprednisolone decreases levels of aspirin by increasing renal clearance. Minor/Significance Unknown.

• metoclopramide intranasal

  Serious - Use Alternative (2)codeine, metoclopramide intranasal. Either increases effects of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Avoid use of metoclopramide intranasal or interacting drug, depending on importance of drug to patient.
  
  carisoprodol, metoclopramide intranasal. Either increases effects of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Avoid use of metoclopramide intranasal or interacting drug, depending on importance of drug to patient.

• metolazone

  Monitor Closely (1)aspirin increases and metolazone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.Minor (1)metolazone will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• metoprolol

  Monitor Closely (2)aspirin decreases effects of metoprolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  metoprolol and aspirin both increase serum potassium. Use Caution/Monitor.

• midazolam

  Monitor Closely (2)midazolam and carisoprodol both increase sedation. Use Caution/Monitor.
  
  midazolam and codeine both increase sedation. Use Caution/Monitor.

• midazolam intranasal

  Monitor Closely (2)midazolam intranasal, codeine. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Concomitant use of barbiturates, alcohol, or other CNS depressants may increase the risk of hypoventilation, airway obstruction, desaturation, or apnea and may contribute to profound and/or prolonged drug effect.
  
  midazolam intranasal, carisoprodol. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Concomitant use of barbiturates, alcohol, or other CNS depressants may increase the risk of hypoventilation, airway obstruction, desaturation, or apnea and may contribute to profound and/or prolonged drug effect.

• midodrine

  Monitor Closely (1)codeine increases and midodrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• mifepristone

  Contraindicated (1)aspirin, mifepristone. Other (see comment). Contraindicated. Comment: Aspirin induced antiplatelet activity may induce excessive bleeding after an abortion w/mifepristone (RU 486).Serious - Use Alternative (1)aspirin will decrease the level or effect of mifepristone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• milnacipran

  Monitor Closely (1)milnacipran, aspirin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• mirabegron

  Monitor Closely (1)mirabegron will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

• mirtazapine

  Monitor Closely (2)codeine and mirtazapine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and mirtazapine both increase sedation. Use Caution/Monitor.

• mistletoe

  Monitor Closely (1)aspirin increases and mistletoe decreases anticoagulation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• mitotane

  Serious - Use Alternative (1)aspirin will decrease the level or effect of mitotane by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• modafinil

  Monitor Closely (1)codeine increases and modafinil decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• moexipril

  Monitor Closely (1)moexipril, aspirin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly with high dose aspirin, in elderly or volume depleted individuals.Serious - Use Alternative (1)aspirin, moexipril. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Coadministration may result in a significant decrease in renal function. NSAIDs may diminish the antihypertensive effect of ACE inhibitors. The mechanism of these interactions is likely related to the ability of NSAIDs to reduce the synthesis of vasodilating renal prostaglandins.

• morphine

  Monitor Closely (2)codeine and morphine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and morphine both increase sedation. Use Caution/Monitor.

• motherwort

  Monitor Closely (2)codeine and motherwort both increase sedation. Use Caution/Monitor.
  
  carisoprodol and motherwort both increase sedation. Use Caution/Monitor.

• moxisylyte

  Monitor Closely (1)aspirin decreases effects of moxisylyte by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.

• moxonidine

  Monitor Closely (2)codeine and moxonidine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and moxonidine both increase sedation. Use Caution/Monitor.

• mycophenolate

  Monitor Closely (1)aspirin will increase the level or effect of mycophenolate by acidic (anionic) drug competition for renal tubular clearance. Use Caution/Monitor.

• nabilone

  Monitor Closely (2)codeine and nabilone both increase sedation. Use Caution/Monitor.
  
  carisoprodol and nabilone both increase sedation. Use Caution/Monitor.

• nabumetone

  Monitor Closely (2)aspirin and nabumetone both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and nabumetone both increase serum potassium. Use Caution/Monitor.Minor (1)aspirin will increase the level or effect of nabumetone by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• nadolol

  Monitor Closely (2)aspirin decreases effects of nadolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  nadolol and aspirin both increase serum potassium. Use Caution/Monitor.

• nafcillin

  Monitor Closely (2)nafcillin, aspirin. Either increases levels of the other by plasma protein binding competition. Use Caution/Monitor.
  
  nafcillin, aspirin. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor.

• nalbuphine

  Monitor Closely (2)codeine and nalbuphine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and nalbuphine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)nalbuphine, codeine. Other (see comment). Avoid or Use Alternate Drug. Comment: Mixed opiate agonist/antagonists usually produce additive sedation with narcotics; however, in narcotic addicted pts., the antagonist activity may provoke withdrawal Sx.

• naproxen

  Monitor Closely (2)aspirin and naproxen both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and naproxen both increase serum potassium. Use Caution/Monitor.Minor (1)aspirin will increase the level or effect of naproxen by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• nebivolol

  Monitor Closely (2)aspirin decreases effects of nebivolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  nebivolol and aspirin both increase serum potassium. Use Caution/Monitor.

• nefazodone

  Monitor Closely (1)nefazodone, aspirin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.

• neomycin PO

  Minor (1)aspirin increases levels of neomycin PO by decreasing renal clearance. Minor/Significance Unknown. Interaction mainly occurs in preterm infants.

• nettle

  Monitor Closely (1)aspirin increases and nettle decreases anticoagulation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• nilotinib

  Minor (1)nilotinib will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• nitazoxanide

  Monitor Closely (1)nitazoxanide, aspirin. Either increases levels of the other by Mechanism: plasma protein binding competition. Use Caution/Monitor.

• nitroglycerin rectal

  Monitor Closely (1)aspirin will increase the level or effect of nitroglycerin rectal by Other (see comment). Use Caution/Monitor. The pharmacological effects of nitroglycerin may be enhanced by concomitant administration of aspirin.

• nitroglycerin sublingual

  Monitor Closely (1)aspirin increases effects of nitroglycerin sublingual by additive vasodilation. Use Caution/Monitor. Vasodilatory and hemodynamic effects of NTG may be enhanced by coadministration with aspirin (additive effect desirable for emergent treatment).

• noni juice

  Minor (1)aspirin and noni juice both increase serum potassium. Minor/Significance Unknown.

• norepinephrine

  Monitor Closely (2)aspirin increases and norepinephrine decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  codeine increases and norepinephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• nortriptyline

  Monitor Closely (2)codeine and nortriptyline both increase sedation. Use Caution/Monitor.
  
  carisoprodol and nortriptyline both increase sedation. Use Caution/Monitor.

• ofloxacin

  Minor (1)ofloxacin, aspirin. Other (see comment). Minor/Significance Unknown. Comment: Risk of CNS stimulation/seizure. Mechanism: Displacement of GABA from receptors in brain.

• olanzapine

  Monitor Closely (2)codeine and olanzapine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and olanzapine both increase sedation. Use Caution/Monitor.

• oliceridine

  Monitor Closely (3)oliceridine, carisoprodol. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.
  
  carisoprodol increases toxicity of oliceridine by Other (see comment). Modify Therapy/Monitor Closely. Comment: Anticholinergic drugs may increase risk of urinary retention and/or severe constipation, which may lead to paralytic ileus. Monitor for signs of urinary retention or reduced gastric motility if oliceridine is coadministered with anticholinergics.
  
  oliceridine, codeine. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

• olmesartan

  Monitor Closely (3)olmesartan, aspirin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  aspirin decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  olmesartan and aspirin both increase serum potassium. Use Caution/Monitor.

• olopatadine intranasal

  Serious - Use Alternative (2)codeine and olopatadine intranasal both increase sedation. Avoid or Use Alternate Drug. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment.
  
  carisoprodol and olopatadine intranasal both increase sedation. Avoid or Use Alternate Drug. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment.

• ombitasvir/paritaprevir/ritonavir & dasabuvir (DSC)

  Monitor Closely (1)ombitasvir/paritaprevir/ritonavir & dasabuvir (DSC) decreases effects of carisoprodol by unspecified interaction mechanism. Modify Therapy/Monitor Closely. Increase dose if clinically indicated.

• omega 3 carboxylic acids

  Monitor Closely (1)omega 3 carboxylic acids, aspirin. Other (see comment). Use Caution/Monitor. Comment: Patients taking omega-3 acids and an anticoagulant or other drug affecting coagulation should be monitored periodically due to potential increased risk of bleeding.

• omega 3 fatty acids

  Monitor Closely (1)omega 3 fatty acids, aspirin. Other (see comment). Use Caution/Monitor. Comment: Patients taking omega-3-fatty acids and an anticoagulant or other drug affecting coagulation should be monitored periodically due to potential increased risk of bleeding. .

• opium tincture

  Monitor Closely (2)carisoprodol and opium tincture both increase sedation. Use Caution/Monitor.
  
  codeine and opium tincture both increase sedation. Use Caution/Monitor.

• orphenadrine

  Monitor Closely (2)carisoprodol and orphenadrine both increase sedation. Use Caution/Monitor.
  
  orphenadrine and codeine both increase sedation. Use Caution/Monitor.

• ospemifene

  Monitor Closely (1)aspirin, ospemifene. Either increases levels of the other by plasma protein binding competition. Modify Therapy/Monitor Closely.

• oxacillin

  Monitor Closely (2)oxacillin, aspirin. Either increases levels of the other by plasma protein binding competition. Use Caution/Monitor.
  
  oxacillin, aspirin. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor.

• oxaprozin

  Monitor Closely (2)aspirin and oxaprozin both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and oxaprozin both increase serum potassium. Use Caution/Monitor.Minor (1)aspirin will increase the level or effect of oxaprozin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• oxazepam

  Monitor Closely (2)oxazepam and codeine both increase sedation. Use Caution/Monitor.
  
  oxazepam and carisoprodol both increase sedation. Use Caution/Monitor.

• oxycodone

  Monitor Closely (2)carisoprodol and oxycodone both increase sedation. Use Caution/Monitor.
  
  codeine and oxycodone both increase sedation. Use Caution/Monitor.

• oxymorphone

  Monitor Closely (2)codeine and oxymorphone both increase sedation. Use Caution/Monitor.
  
  carisoprodol and oxymorphone both increase sedation. Use Caution/Monitor.

• ozanimod

  Serious - Use Alternative (1)ozanimod and codeine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Avoid or Use Alternate Drug. Because the active metabolite of ozanimod inhibits MAO-B in vitro, there is a potential for serious adverse reactions, including hypertensive crisis. Therefore, coadministration of ozanimod with drugs that can increase norepinephrine or serotonin is not recommended. Monitor for hypertension with concomitant use.

• paliperidone

  Monitor Closely (2)carisoprodol and paliperidone both increase sedation. Use Caution/Monitor.
  
  codeine and paliperidone both increase sedation. Use Caution/Monitor.

• panax ginseng

  Monitor Closely (1)aspirin and panax ginseng both increase anticoagulation. Use Caution/Monitor.

• papaveretum

  Monitor Closely (2)codeine and papaveretum both increase sedation. Use Caution/Monitor.
  
  carisoprodol and papaveretum both increase sedation. Use Caution/Monitor.

• papaverine

  Monitor Closely (2)carisoprodol and papaverine both increase sedation. Use Caution/Monitor.
  
  codeine and papaverine both increase sedation. Use Caution/Monitor.

• parecoxib

  Monitor Closely (2)aspirin and parecoxib both increase serum potassium. Use Caution/Monitor.
  
  aspirin and parecoxib both increase anticoagulation. Use Caution/Monitor.Minor (2)parecoxib will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.
  
  aspirin will increase the level or effect of parecoxib by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• paromomycin

  Minor (1)aspirin increases levels of paromomycin by decreasing renal clearance. Minor/Significance Unknown. Interaction mainly occurs in preterm infants.

• paroxetine

  Monitor Closely (2)paroxetine, aspirin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.
  
  paroxetine will decrease the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• pau d'arco

  Monitor Closely (1)aspirin and pau d'arco both increase anticoagulation. Use Caution/Monitor.

• pegaspargase

  Monitor Closely (1)pegaspargase increases effects of aspirin by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of bleeding events.

• peginterferon alfa 2b

  Monitor Closely (1)peginterferon alfa 2b, codeine. Other (see comment). Use Caution/Monitor. Comment: When patients are administered peginterferon alpha-2b with CYP2D6 substrates, the therapeutic effect of these drugs may be altered. Peginterferon alpha-2b may increase or decrease levels of CYP2D6 substrate.

• pegvisomant

  Monitor Closely (1)codeine decreases effects of pegvisomant by unknown mechanism. Use Caution/Monitor.

• pemetrexed

  Serious - Use Alternative (1)aspirin increases levels of pemetrexed by unspecified interaction mechanism. Avoid or Use Alternate Drug. Interrupt dosing in all patients taking NSAIDs with long elimination half-lives for at least 5d before, the day of, and 2d following pemetrexed administration. If coadministration of an NSAID is necessary, closely monitor patients for toxicity, especially myelosuppression, renal toxicity, and GI toxicity.

• penbutolol

  Monitor Closely (2)aspirin decreases effects of penbutolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  penbutolol and aspirin both increase serum potassium. Use Caution/Monitor.

• penicillin G aqueous

  Monitor Closely (2)penicillin G aqueous, aspirin. Either increases levels of the other by plasma protein binding competition. Use Caution/Monitor.
  
  penicillin G aqueous, aspirin. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor.

• penicillin VK

  Minor (1)penicillin VK, aspirin. Either increases levels of the other by decreasing renal clearance. Minor/Significance Unknown.

• pentazocine

  Monitor Closely (2)codeine and pentazocine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and pentazocine both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)pentazocine, codeine. Other (see comment). Avoid or Use Alternate Drug. Comment: Mixed opiate agonist/antagonists usually produce additive sedation with narcotics; however, in narcotic addicted pts., the antagonist activity may provoke withdrawal Sx.Minor (1)aspirin, pentazocine. Either increases toxicity of the other by pharmacodynamic synergism. Minor/Significance Unknown. Possible risk of renal papillary necrosis w/chronic Tx.

• pentobarbital

  Monitor Closely (2)pentobarbital and carisoprodol both increase sedation. Use Caution/Monitor.
  
  pentobarbital and codeine both increase sedation. Use Caution/Monitor.

• perampanel

  Monitor Closely (1)perampanel and codeine both increase sedation. Use Caution/Monitor.

• perindopril

  Monitor Closely (1)perindopril, aspirin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly with high doses of aspirin,in elderly or volume depleted individuals.Serious - Use Alternative (1)aspirin, perindopril. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Coadministration may result in a significant decrease in renal function. NSAIDs may diminish the antihypertensive effect of ACE inhibitors. The mechanism of these interactions is likely related to the ability of NSAIDs to reduce the synthesis of vasodilating renal prostaglandins.

• perphenazine

  Monitor Closely (2)codeine and perphenazine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and perphenazine both increase sedation. Use Caution/Monitor.Minor (2)perphenazine will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.
  
  perphenazine decreases effects of codeine by decreasing metabolism. Minor/Significance Unknown. Decreased conversion of codeine to active metabolite morphine.

• phendimetrazine

  Monitor Closely (1)codeine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• phenelzine

  Serious - Use Alternative (1)phenelzine increases toxicity of codeine by unknown mechanism. Avoid or Use Alternate Drug. Risk of hypotension, hyperpyrexia, somnolence, or death; separate by 14 d.

• phenindione

  Monitor Closely (1)phenindione and aspirin both increase anticoagulation. Modify Therapy/Monitor Closely.

• phenobarbital

  Monitor Closely (2)phenobarbital and codeine both increase sedation. Use Caution/Monitor.
  
  phenobarbital and carisoprodol both increase sedation. Use Caution/Monitor.

• phenoxybenzamine

  Monitor Closely (1)aspirin decreases effects of phenoxybenzamine by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.

• phentermine

  Monitor Closely (1)codeine increases and phentermine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• phentolamine

  Monitor Closely (1)aspirin decreases effects of phentolamine by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.

• phenylephrine

  Monitor Closely (1)codeine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• phenylephrine PO

  Monitor Closely (2)codeine increases and phenylephrine PO decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. .
  
  carisoprodol increases and phenylephrine PO decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. .

• pholcodine

  Monitor Closely (2)carisoprodol and pholcodine both increase sedation. Use Caution/Monitor.
  
  codeine and pholcodine both increase sedation. Use Caution/Monitor.

• phytoestrogens

  Monitor Closely (1)aspirin and phytoestrogens both increase anticoagulation. Use Caution/Monitor.

• pimozide

  Monitor Closely (2)codeine and pimozide both increase sedation. Use Caution/Monitor.
  
  carisoprodol and pimozide both increase sedation. Use Caution/Monitor.

• pindolol

  Monitor Closely (2)aspirin decreases effects of pindolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  pindolol and aspirin both increase serum potassium. Use Caution/Monitor.

• piperacillin

  Minor (1)piperacillin, aspirin. Either increases effects of the other by receptor binding competition. Minor/Significance Unknown. Salicylic acid could be displaced from protein binding sites or it could itself displace other protein-bound drugs and result in an enhanced effect of the displaced drug.

• pirbuterol

  Monitor Closely (2)aspirin increases and pirbuterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  codeine increases and pirbuterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• piroxicam

  Monitor Closely (2)aspirin and piroxicam both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and piroxicam both increase serum potassium. Use Caution/Monitor.Minor (1)aspirin will increase the level or effect of piroxicam by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• pivmecillinam

  Monitor Closely (2)pivmecillinam, aspirin. Either increases levels of the other by plasma protein binding competition. Use Caution/Monitor.
  
  pivmecillinam, aspirin. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor.

• potassium acid phosphate

  Monitor Closely (1)aspirin and potassium acid phosphate both increase serum potassium. Modify Therapy/Monitor Closely.

• potassium chloride

  Monitor Closely (1)aspirin and potassium chloride both increase serum potassium. Modify Therapy/Monitor Closely.

• potassium citrate

  Monitor Closely (1)aspirin and potassium citrate both increase serum potassium. Use Caution/Monitor.

• potassium iodide

  Monitor Closely (1)potassium iodide and aspirin both increase serum potassium. Use Caution/Monitor.

• prabotulinumtoxinA

  Monitor Closely (1)carisoprodol increases effects of prabotulinumtoxinA by pharmacodynamic synergism. Use Caution/Monitor. Muscle relaxants may enhance botulinum toxin effects. Closely monitor for increased neuromuscular blockade.

• prasugrel

  Monitor Closely (1)aspirin, prasugrel. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; monitor closely.Serious - Use Alternative (1)codeine will decrease the level or effect of prasugrel by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Co-administration of opioid agonists delay and reduce absorption of prasugrel and its active metabolite presumably by slowing gastric emptying; consider the use of a parenteral anti-platelet agent in acute coronary syndrome patients requiring co-administration of opioid agonists

• prazosin

  Monitor Closely (1)aspirin decreases effects of prazosin by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.

• prednisolone

  Monitor Closely (1)aspirin, prednisolone. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of GI ulceration.Minor (1)prednisolone decreases levels of aspirin by increasing renal clearance. Minor/Significance Unknown.

• prednisone

  Monitor Closely (1)aspirin, prednisone. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of GI ulceration.Minor (1)prednisone decreases levels of aspirin by increasing renal clearance. Minor/Significance Unknown.

• pregabalin

  Monitor Closely (1)pregabalin, codeine. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of CNS depressants can result in serious, life-threatening, and fatal respiratory depression. Use lowest dose possible and monitor for respiratory depression and sedation.

• primidone

  Monitor Closely (2)primidone and carisoprodol both increase sedation. Use Caution/Monitor.
  
  primidone and codeine both increase sedation. Use Caution/Monitor.

• probenecid

  Serious - Use Alternative (1)aspirin decreases effects of probenecid by acidic (anionic) drug competition for renal tubular clearance. Avoid or Use Alternate Drug. Aspirin decreases uricosuric action of probenecid.

• procarbazine

  Serious - Use Alternative (1)procarbazine increases toxicity of codeine by unknown mechanism. Avoid or Use Alternate Drug. MAOIs may potentiate CNS depression and hypotension. Do not use within 14 days of MAOI use. .

• prochlorperazine

  Monitor Closely (2)codeine and prochlorperazine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and prochlorperazine both increase sedation. Use Caution/Monitor.

• promethazine

  Monitor Closely (2)promethazine and carisoprodol both increase sedation. Use Caution/Monitor.
  
  promethazine and codeine both increase sedation. Use Caution/Monitor.

• propafenone

  Minor (2)propafenone will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.
  
  propafenone decreases effects of codeine by decreasing metabolism. Minor/Significance Unknown. Decreased conversion of codeine to active metabolite morphine.

• propofol

  Monitor Closely (2)propofol and carisoprodol both increase sedation. Use Caution/Monitor.
  
  propofol and codeine both increase sedation. Use Caution/Monitor.

• propranolol

  Monitor Closely (2)aspirin decreases effects of propranolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  propranolol and aspirin both increase serum potassium. Use Caution/Monitor.

• propylhexedrine

  Monitor Closely (2)codeine increases and propylhexedrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  carisoprodol increases and propylhexedrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• protamine

  Monitor Closely (1)protamine and aspirin both increase anticoagulation. Modify Therapy/Monitor Closely.

• protriptyline

  Monitor Closely (2)codeine and protriptyline both increase sedation. Use Caution/Monitor.
  
  carisoprodol and protriptyline both increase sedation. Use Caution/Monitor.

• quazepam

  Monitor Closely (2)quazepam and codeine both increase sedation. Use Caution/Monitor.
  
  quazepam and carisoprodol both increase sedation. Use Caution/Monitor.

• quetiapine

  Monitor Closely (2)codeine and quetiapine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and quetiapine both increase sedation. Use Caution/Monitor.

• quinacrine

  Minor (2)quinacrine will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.
  
  quinacrine decreases effects of codeine by decreasing metabolism. Minor/Significance Unknown. Decreased conversion of codeine to active metabolite morphine.

• quinapril

  Monitor Closely (1)quinapril, aspirin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly with high doses of aspirin, in elderly or volume depleted individuals.Serious - Use Alternative (1)aspirin, quinapril. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Coadministration may result in a significant decrease in renal function. NSAIDs may diminish the antihypertensive effect of ACE inhibitors. The mechanism of these interactions is likely related to the ability of NSAIDs to reduce the synthesis of vasodilating renal prostaglandins.

• quinidine

  Monitor Closely (1)quinidine will decrease the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• ramelteon

  Monitor Closely (2)codeine and ramelteon both increase sedation. Use Caution/Monitor.
  
  carisoprodol and ramelteon both increase sedation. Use Caution/Monitor.

• ramipril

  Monitor Closely (1)ramipril, aspirin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly with high doses of aspirin, in elderly or volume depleted individuals.Serious - Use Alternative (1)aspirin, ramipril. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Coadministration may result in a significant decrease in renal function. NSAIDs may diminish the antihypertensive effect of ACE inhibitors. The mechanism of these interactions is likely related to the ability of NSAIDs to reduce the synthesis of vasodilating renal prostaglandins.

• ranolazine

  Minor (1)ranolazine will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• rasagiline

  Serious - Use Alternative (1)rasagiline increases toxicity of codeine by unknown mechanism. Avoid or Use Alternate Drug. Risk of hypotension, hyperpyrexia, somnolence, or death.

• reishi

  Monitor Closely (1)aspirin and reishi both increase anticoagulation. Use Caution/Monitor.

• remimazolam

  Monitor Closely (2)remimazolam, carisoprodol. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely. Coadministration may result in profound sedation, respiratory depression, coma, and/or death. Continuously monitor vital signs during sedation and recovery period if coadministered. Carefully titrate remimazolam dose if administered with opioid analgesics and/or sedative/hypnotics.
  
  remimazolam, codeine. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely. Coadministration may result in profound sedation, respiratory depression, coma, and/or death. Continuously monitor vital signs during sedation and recovery period if coadministered. Carefully titrate remimazolam dose if administered with opioid analgesics and/or sedative/hypnotics.

• reteplase

  Monitor Closely (1)aspirin, reteplase. Either increases toxicity of the other by anticoagulation. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; monitor closely.

• ribociclib

  Monitor Closely (1)ribociclib will increase the level or effect of codeine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• risperidone

  Monitor Closely (2)codeine and risperidone both increase sedation. Use Caution/Monitor.
  
  carisoprodol and risperidone both increase sedation. Use Caution/Monitor.

• ritonavir

  Monitor Closely (1)ritonavir will decrease the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• rivaroxaban

  Monitor Closely (1)aspirin, rivaroxaban. Either increases toxicity of the other by anticoagulation. Use Caution/Monitor. Both drugs have the potential to cause bleeding. The need for simultaneous use of low-dose aspirin (<100 mg/day) with anticoagulants are common for patients with cardiovascular disease, but may result in increased bleeding; monitor closely. Promptly evaluate any signs or symptoms of blood loss if treated concomitantly with low-dose aspirin. Avoid coadministration with chronic use of higher dose aspirin.

• rivastigmine

  Monitor Closely (1)rivastigmine increases toxicity of aspirin by pharmacodynamic synergism. Use Caution/Monitor. Monitor patients for symptoms of active or occult gastrointestinal bleeding.

• rolapitant

  Monitor Closely (1)rolapitant will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Rolapitant may increase plasma concentrations of CYP2D6 substrates for at least 28 days following rolapitant administration.

• rose hips

  Minor (3)rose hips will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
  
  aspirin decreases levels of rose hips by increasing renal clearance. Minor/Significance Unknown.
  
  rose hips increases levels of aspirin by decreasing renal clearance. Minor/Significance Unknown.

• rucaparib

  Monitor Closely (1)rucaparib will increase the level or effect of carisoprodol by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Adjust dosage of CYP2C19 substrates, if clinically indicated.

• sacubitril/valsartan

  Monitor Closely (3)sacubitril/valsartan, aspirin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  aspirin decreases effects of sacubitril/valsartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  sacubitril/valsartan and aspirin both increase serum potassium. Use Caution/Monitor.

• sage

  Minor (2)codeine and sage both increase sedation. Minor/Significance Unknown.
  
  carisoprodol and sage both increase sedation. Minor/Significance Unknown.

• salicylates (non-asa)

  Monitor Closely (2)aspirin and salicylates (non-asa) both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and salicylates (non-asa) both increase serum potassium. Use Caution/Monitor.Minor (1)aspirin will increase the level or effect of salicylates (non-asa) by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• salmeterol

  Monitor Closely (2)codeine increases and salmeterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  aspirin increases and salmeterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• salsalate

  Monitor Closely (2)aspirin and salsalate both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and salsalate both increase serum potassium. Use Caution/Monitor.Minor (1)aspirin will increase the level or effect of salsalate by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• saw palmetto

  Monitor Closely (1)saw palmetto increases toxicity of aspirin by unspecified interaction mechanism. Use Caution/Monitor. May increase risk of bleeding.

• scullcap

  Monitor Closely (2)codeine and scullcap both increase sedation. Use Caution/Monitor.
  
  carisoprodol and scullcap both increase sedation. Use Caution/Monitor.

• secobarbital

  Monitor Closely (2)secobarbital and codeine both increase sedation. Use Caution/Monitor.
  
  secobarbital and carisoprodol both increase sedation. Use Caution/Monitor.

• selegiline

  Monitor Closely (1)selegiline increases toxicity of codeine by unknown mechanism. Modify Therapy/Monitor Closely. Potential for increased CNS depression, drowsiness, dizziness or hypotension, so use with any MAOI should be cautious.

• selegiline transdermal

  Serious - Use Alternative (1)selegiline transdermal increases toxicity of codeine by unknown mechanism. Avoid or Use Alternate Drug. Risk of hypotension, hyperpyrexia, somnolence, or death.

• selinexor

  Serious - Use Alternative (2)selinexor, codeine. unspecified interaction mechanism. Avoid or Use Alternate Drug. Patients treated with selinexor may experience neurological toxicities. Avoid taking selinexor with other medications that may cause dizziness or confusion.
  
  selinexor, carisoprodol. unspecified interaction mechanism. Avoid or Use Alternate Drug. Patients treated with selinexor may experience neurological toxicities. Avoid taking selinexor with other medications that may cause dizziness or confusion.

• selumetinib

  Monitor Closely (1)aspirin and selumetinib both increase anticoagulation. Modify Therapy/Monitor Closely. An increased risk of bleeding may occur in patients taking a vitamin-K antagonist or an antiplatelet agent with selumetinib. Monitor for bleeding and INR or PT in patients coadministered a vitamin-K antagonist or an antiplatelet agent with selumetinib.

• sertraline

  Monitor Closely (2)sertraline decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.
  
  sertraline, aspirin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.Minor (1)sertraline decreases effects of codeine by decreasing metabolism. Minor/Significance Unknown. Decreased conversion of codeine to active metabolite morphine.

• sevoflurane

  Monitor Closely (1)sevoflurane and codeine both increase sedation. Use Caution/Monitor.

• shepherd's purse

  Monitor Closely (2)carisoprodol and shepherd's purse both increase sedation. Use Caution/Monitor.
  
  codeine and shepherd's purse both increase sedation. Use Caution/Monitor.

• Siberian ginseng

  Monitor Closely (1)aspirin and Siberian ginseng both increase anticoagulation. Use Caution/Monitor.

• silodosin

  Monitor Closely (1)aspirin decreases effects of silodosin by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.

• sodium bicarbonate

  Minor (1)sodium bicarbonate, aspirin. Mechanism: passive renal tubular reabsorption due to increased pH. Minor/Significance Unknown. Salicylate levels increased at moderate doses; salicylate levels decreased at large doses (d/t increased renal excretion of unchanged salicylic acid).

• sodium citrate/citric acid

  Minor (1)sodium citrate/citric acid, aspirin. Mechanism: passive renal tubular reabsorption due to increased pH. Minor/Significance Unknown. Salicylate levels increased at moderate doses; salicylate levels decreased at large doses (d/t increased renal excretion of unchanged salicylic acid).

• sodium oxybate

  Serious - Use Alternative (2)codeine, sodium oxybate. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.
  
  carisoprodol, sodium oxybate. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

• sodium picosulfate/magnesium oxide/anhydrous citric acid

  Monitor Closely (1)aspirin, sodium picosulfate/magnesium oxide/anhydrous citric acid. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May be associated with fluid and electrolyte imbalances.

• sodium sulfate/?magnesium sulfate/potassium chloride

  Monitor Closely (1)sodium sulfate/?magnesium sulfate/potassium chloride increases toxicity of aspirin by Other (see comment). Use Caution/Monitor. Comment: Coadministration with medications that cause fluid and electrolyte abnormalities may increase the risk of adverse events of seizure, arrhythmias, and renal impairment.

• sodium sulfate/potassium sulfate/magnesium sulfate

  Monitor Closely (1)sodium sulfate/potassium sulfate/magnesium sulfate increases toxicity of aspirin by Other (see comment). Use Caution/Monitor. Comment: Coadministration with medications that cause fluid and electrolyte abnormalities may increase the risk of adverse events of seizure, arrhythmias, and renal impairment.

• sotalol

  Monitor Closely (2)aspirin decreases effects of sotalol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  sotalol and aspirin both increase serum potassium. Use Caution/Monitor.

• sparsentan

  Monitor Closely (2)sparsentan will decrease the level or effect of carisoprodol by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. Sparsentan (a CYP2C19 inducer) decreases exposure of CYP2C19 substrates and reduces efficacy related to these substrates.
  
  aspirin and sparsentan both increase nephrotoxicity and/or ototoxicity. Use Caution/Monitor. Coadministration of NSAIDS, including selective COX-2 inhibitors, may result in deterioration of kidney function (eg, possible kidney failure). Monitor for signs of worsening renal function with concomitant use with NSAIDs.

• spironolactone

  Monitor Closely (2)aspirin decreases effects of spironolactone by unspecified interaction mechanism. Use Caution/Monitor. When used concomitantly, spironolactone dose may need to be titrated to higher maintenance dose and the patient should be observed closely to determine if the desired effect is obtained.
  
  spironolactone and aspirin both increase serum potassium. Modify Therapy/Monitor Closely.

• stiripentol

  Monitor Closely (3)stiripentol, carisoprodol. Either increases effects of the other by sedation. Use Caution/Monitor. Concurrent use of medications with CNS depressant effects together with thalidomide should be avoided due to the risk for additive sedative effects.
  
  stiripentol will increase the level or effect of carisoprodol by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Consider reducing the dose of CYP2C19 substrates, if adverse reactions are experienced when administered concomitantly with stiripentol.
  
  stiripentol, codeine. Either increases effects of the other by sedation. Use Caution/Monitor. Concomitant use stiripentol with other CNS depressants, including alcohol, may increase the risk of sedation and somnolence.Minor (1)aspirin will decrease the level or effect of stiripentol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• streptomycin

  Minor (1)aspirin increases levels of streptomycin by decreasing renal clearance. Minor/Significance Unknown. Interaction mainly occurs in preterm infants.

• succinylcholine

  Monitor Closely (1)aspirin and succinylcholine both increase serum potassium. Use Caution/Monitor.

• sufentanil

  Monitor Closely (2)codeine and sufentanil both increase sedation. Use Caution/Monitor.
  
  carisoprodol and sufentanil both increase sedation. Use Caution/Monitor.

• sufentanil SL

  Serious - Use Alternative (2)sufentanil SL, codeine. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration may result in hypotension, profound sedation, respiratory depression, coma, and death. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.
  
  sufentanil SL, carisoprodol. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration may result in hypotension, profound sedation, respiratory depression, coma, and death. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

• sulfadiazine

  Minor (1)aspirin increases levels of sulfadiazine by unspecified interaction mechanism. Minor/Significance Unknown.

• sulfamethoxazole

  Monitor Closely (1)aspirin, sulfamethoxazole. Either increases effects of the other by plasma protein binding competition. Use Caution/Monitor. Due to high protein binding capacity of both drugs, one may displace the other when coadministered leading to an enhanced effect of the displaced drug; risk is low with low dose aspirin.

• sulfasalazine

  Monitor Closely (2)aspirin and sulfasalazine both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and sulfasalazine both increase serum potassium. Use Caution/Monitor.Minor (1)aspirin will increase the level or effect of sulfasalazine by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• sulfisoxazole

  Minor (1)aspirin increases levels of sulfisoxazole by unspecified interaction mechanism. Minor/Significance Unknown.

• sulindac

  Monitor Closely (2)aspirin and sulindac both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and sulindac both increase serum potassium. Use Caution/Monitor.Minor (1)aspirin will increase the level or effect of sulindac by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• suvorexant

  Monitor Closely (1)suvorexant and codeine both increase sedation. Modify Therapy/Monitor Closely. Dosage adjustments of suvorexant and concomitant CNS depressants may be necessary

• tafluprost

  Monitor Closely (1)tafluprost, aspirin. unspecified interaction mechanism. Use Caution/Monitor. There are conflicting reports from studies of either increased or decreased IOP when ophthalmic prostaglandins are coadministered with NSAIDs (either systemic or ophthalmic).

• tapentadol

  Monitor Closely (2)codeine and tapentadol both increase sedation. Use Caution/Monitor.
  
  carisoprodol and tapentadol both increase sedation. Use Caution/Monitor.

• tecovirimat

  Monitor Closely (1)tecovirimat will increase the level or effect of carisoprodol by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. Tecovirimat is a weak inhibitor of CYP2C8 and CYP2C19. Monitor for adverse effects if coadministered with sensitive substrates of these enzymes.

• telmisartan

  Monitor Closely (3)telmisartan, aspirin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  aspirin decreases effects of telmisartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  telmisartan and aspirin both increase serum potassium. Use Caution/Monitor.

• temazepam

  Monitor Closely (2)temazepam and codeine both increase sedation. Use Caution/Monitor.
  
  temazepam and carisoprodol both increase sedation. Use Caution/Monitor.

• temocillin

  Monitor Closely (2)temocillin, aspirin. Either increases levels of the other by plasma protein binding competition. Use Caution/Monitor.
  
  temocillin, aspirin. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor.

• tenecteplase

  Monitor Closely (1)aspirin, tenecteplase. Either increases toxicity of the other by anticoagulation. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; monitor closely.

• teniposide

  Minor (1)aspirin increases levels of teniposide by unspecified interaction mechanism. Minor/Significance Unknown.

• terazosin

  Monitor Closely (1)aspirin decreases effects of terazosin by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.

• terbinafine

  Monitor Closely (1)terbinafine will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Assess need to reduce dose of CYP2D6-metabolized drug.

• terbutaline

  Monitor Closely (2)codeine increases and terbutaline decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  aspirin increases and terbutaline decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• thioridazine

  Monitor Closely (3)thioridazine decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.
  
  codeine and thioridazine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and thioridazine both increase sedation. Use Caution/Monitor.Minor (1)thioridazine decreases effects of codeine by decreasing metabolism. Minor/Significance Unknown. Decreased conversion of codeine to active metabolite morphine.

• thiothixene

  Monitor Closely (2)codeine and thiothixene both increase sedation. Use Caution/Monitor.
  
  carisoprodol and thiothixene both increase sedation. Use Caution/Monitor.

• ticagrelor

  Monitor Closely (1)aspirin, ticagrelor. Other (see comment). Use Caution/Monitor. Comment: Maintenance doses of aspirin above 100 mg decreases effectiveness of ticagrelor. Therefore, after the initial loading dose of aspirin (usually 325 mg), use ticagrelor with a maintenance dose of aspirin of 75-100 mg.Serious - Use Alternative (1)codeine will decrease the level or effect of ticagrelor by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Co-administration of opioid agonists delay and reduce absorption of ticagrelor and its active metabolite presumably by slowing gastric emptying; consider the use of a parenteral anti-platelet agent in acute coronary syndrome patients requiring co-administration of opioid agonists

• ticarcillin

  Monitor Closely (2)ticarcillin, aspirin. Either increases levels of the other by plasma protein binding competition. Use Caution/Monitor.
  
  ticarcillin, aspirin. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor.

• ticlopidine

  Monitor Closely (1)ticlopidine decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.Serious - Use Alternative (1)aspirin increases effects of ticlopidine by pharmacodynamic synergism. Avoid or Use Alternate Drug. Enhanced risk of hemorrhage.

• tiludronate

  Minor (1)aspirin decreases levels of tiludronate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• timolol

  Monitor Closely (2)aspirin decreases effects of timolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis.
  
  timolol and aspirin both increase serum potassium. Use Caution/Monitor.

• tipranavir

  Minor (1)tipranavir will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

• tirofiban

  Monitor Closely (1)aspirin, tirofiban. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. The need for simultaneous use of low-dose aspirin and anticoagulant or antiplatelet agents are common for patients with cardiovascular disease; monitor closely.

• tobramycin

  Minor (1)aspirin increases levels of tobramycin by decreasing renal clearance. Minor/Significance Unknown. Interaction mainly occurs in preterm infants.

• tobramycin inhaled

  Monitor Closely (1)tobramycin inhaled and aspirin both increase nephrotoxicity and/or ototoxicity. Modify Therapy/Monitor Closely. Avoid concurrent or sequential use to decrease risk for ototoxicity

• tolazamide

  Monitor Closely (1)aspirin increases effects of tolazamide by unknown mechanism. Use Caution/Monitor. Risk of hypoglycemia.Minor (1)aspirin increases effects of tolazamide by plasma protein binding competition. Minor/Significance Unknown. Large dose of salicylate.

• tolbutamide

  Monitor Closely (1)aspirin increases effects of tolbutamide by unknown mechanism. Use Caution/Monitor. Risk of hypoglycemia.Minor (1)aspirin increases effects of tolbutamide by plasma protein binding competition. Minor/Significance Unknown. Large dose of salicylate.

• tolfenamic acid

  Monitor Closely (2)aspirin and tolfenamic acid both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and tolfenamic acid both increase serum potassium. Use Caution/Monitor.Minor (1)aspirin will increase the level or effect of tolfenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• tolmetin

  Monitor Closely (2)aspirin and tolmetin both increase anticoagulation. Use Caution/Monitor.
  
  aspirin and tolmetin both increase serum potassium. Use Caution/Monitor.Minor (1)aspirin will increase the level or effect of tolmetin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• tolvaptan

  Monitor Closely (1)aspirin and tolvaptan both increase serum potassium. Use Caution/Monitor.

• topiramate

  Monitor Closely (2)codeine and topiramate both increase sedation. Modify Therapy/Monitor Closely.
  
  carisoprodol and topiramate both increase sedation. Modify Therapy/Monitor Closely.

• torsemide

  Monitor Closely (1)aspirin increases and torsemide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• tramadol

  Monitor Closely (2)carisoprodol and tramadol both increase sedation. Use Caution/Monitor.
  
  codeine and tramadol both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)tramadol, codeine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tramadol may reinitiate opiate dependence in pts. previously addicted to other opiates; it may also provoke withdrawal Sx. in pts. who are currently opiate dependent.

• trandolapril

  Monitor Closely (1)trandolapril, aspirin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly with high dose aspirin, in elderly and volume depleted.Serious - Use Alternative (1)aspirin, trandolapril. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Coadministration may result in a significant decrease in renal function. NSAIDs may diminish the antihypertensive effect of ACE inhibitors. The mechanism of these interactions is likely related to the ability of NSAIDs to reduce the synthesis of vasodilating renal prostaglandins.

• tranylcypromine

  Monitor Closely (1)tranylcypromine decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.Serious - Use Alternative (1)tranylcypromine increases toxicity of codeine by unknown mechanism. Avoid or Use Alternate Drug. Risk of hypotension, hyperpyrexia, somnolence, or death; separate by 14 d.

• travoprost ophthalmic

  Monitor Closely (1)travoprost ophthalmic, aspirin. unspecified interaction mechanism. Use Caution/Monitor. There are conflicting reports from studies of either increased or decreased IOP when ophthalmic prostaglandins are coadministered with NSAIDs (either systemic or ophthalmic).

• trazodone

  Monitor Closely (3)trazodone, aspirin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.
  
  codeine and trazodone both increase sedation. Use Caution/Monitor.
  
  carisoprodol and trazodone both increase sedation. Use Caution/Monitor.

• triamcinolone acetonide injectable suspension

  Monitor Closely (1)aspirin, triamcinolone acetonide injectable suspension. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Aspirin in conjunction with corticosteroids in hypoprothrombinemia should used with caution. Clearance of salicylates may increase with concurrent use of corticosteroids.Minor (1)triamcinolone acetonide injectable suspension decreases levels of aspirin by increasing renal clearance. Minor/Significance Unknown.

• triamterene

  Monitor Closely (1)triamterene and aspirin both increase serum potassium. Modify Therapy/Monitor Closely.Minor (2)triamterene, aspirin. Other (see comment). Minor/Significance Unknown. Comment: Risk of acute renal failure. Mechanism: NSAIDs decrease prostaglandin synthesis, which normally protect against nephrotoxicity.
  
  aspirin increases toxicity of triamterene by pharmacodynamic antagonism. Minor/Significance Unknown. NSAIDs decrease prostaglandin synthesis, increasing the risk of nephrotoxicity.

• triazolam

  Monitor Closely (2)triazolam and carisoprodol both increase sedation. Use Caution/Monitor.
  
  triazolam and codeine both increase sedation. Use Caution/Monitor.

• triclabendazole

  Monitor Closely (1)triclabendazole will increase the level or effect of carisoprodol by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. If plasma concentrations of the CYP2C19 substrates are elevated during triclabendazole, recheck plasma concentration of the CYP2C19 substrates after discontinuation of triclabendazole.

• triclofos

  Monitor Closely (2)triclofos and codeine both increase sedation. Use Caution/Monitor.
  
  triclofos and carisoprodol both increase sedation. Use Caution/Monitor.

• trifluoperazine

  Monitor Closely (2)codeine and trifluoperazine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and trifluoperazine both increase sedation. Use Caution/Monitor.

• trimipramine

  Monitor Closely (2)codeine and trimipramine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and trimipramine both increase sedation. Use Caution/Monitor.

• triprolidine

  Monitor Closely (1)triprolidine and codeine both increase sedation. Use Caution/Monitor.

• valerian

  Serious - Use Alternative (1)valerian and codeine both increase sedation. Avoid or Use Alternate Drug.

• valganciclovir

  Minor (1)aspirin will increase the level or effect of valganciclovir by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.

• valproic acid

  Monitor Closely (1)aspirin increases levels of valproic acid by plasma protein binding competition. Use Caution/Monitor.

• valsartan

  Monitor Closely (3)valsartan, aspirin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
  
  aspirin decreases effects of valsartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
  
  valsartan and aspirin both increase serum potassium. Use Caution/Monitor.

• vancomycin

  Minor (1)aspirin increases levels of vancomycin by decreasing renal clearance. Minor/Significance Unknown. Interaction mainly occurs in neonates.

• varicella virus vaccine live

  Serious - Use Alternative (1)aspirin, varicella virus vaccine live. Mechanism: unspecified interaction mechanism. Avoid or Use Alternate Drug. Risk of Reye's Syndrome with combination; avoid salicylate use for 6 wks after vaccination.

• venlafaxine

  Monitor Closely (2)venlafaxine will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
  
  venlafaxine, aspirin. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.Minor (1)venlafaxine decreases effects of codeine by decreasing metabolism. Minor/Significance Unknown. Decreased conversion of codeine to active metabolite morphine.

• verapamil

  Minor (1)verapamil increases effects of aspirin by unknown mechanism. Minor/Significance Unknown. Enhanced antiplatelet activity.

• voclosporin

  Monitor Closely (1)voclosporin, aspirin. Either increases toxicity of the other by nephrotoxicity and/or ototoxicity. Modify Therapy/Monitor Closely. Coadministration with drugs associated with nephrotoxicity may increase the risk for acute and/or chronic nephrotoxicity.

• vorapaxar

  Monitor Closely (2)aspirin, vorapaxar. Either increases effects of the other by anticoagulation. Use Caution/Monitor. Coadministration of anticoagulants, antiplatelets, or other drug affecting coagulation should be monitored periodically due to potential increased risk of bleeding.
  
  aspirin, vorapaxar. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Additive antiplatelet effect may occur.

• vortioxetine

  Monitor Closely (1)aspirin, vortioxetine. Either increases effects of the other by anticoagulation. Use Caution/Monitor. Risk minimal with low-dose aspirin.

• warfarin

  Monitor Closely (1)aspirin increases effects of warfarin by anticoagulation. Modify Therapy/Monitor Closely. Avoid coadministration of chronic high-dose aspirin. Aspirin's antiplatelet properties may increase anticoagulation effect of warfarin. The need for simultaneous use of low-dose aspirin and warfarin is common for patients with cardiovascular disease. .

• willow bark

  Minor (2)aspirin will increase the level or effect of willow bark by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
  
  willow bark increases effects of aspirin by pharmacodynamic synergism. Minor/Significance Unknown. Willow bark contains salicylic acid, which may have additive effects/toxicity with salicylate drugs.

• xylometazoline

  Monitor Closely (2)codeine increases and xylometazoline decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
  
  carisoprodol increases and xylometazoline decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• yohimbine

  Monitor Closely (1)codeine increases and yohimbine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

• zafirlukast

  Minor (1)aspirin increases levels of zafirlukast by unknown mechanism. Minor/Significance Unknown.

• zanubrutinib

  Monitor Closely (1)aspirin, zanubrutinib. Either increases effects of the other by anticoagulation. Modify Therapy/Monitor Closely. Zanubrutinib-induced cytopenias increases risk of hemorrhage. Coadministration of zanubritinib with antiplatelets or anticoagulants may further increase this risk.

• ziconotide

  Monitor Closely (2)codeine and ziconotide both increase sedation. Use Caution/Monitor.
  
  carisoprodol and ziconotide both increase sedation. Use Caution/Monitor.Minor (1)ziconotide, codeine. Mechanism: unspecified interaction mechanism. Minor/Significance Unknown. Additive decreased GI motility. Additive analgesia. Ziconotide does NOT potentiate opioid induced respiratory depression.

• ziprasidone

  Monitor Closely (2)codeine and ziprasidone both increase sedation. Use Caution/Monitor.
  
  carisoprodol and ziprasidone both increase sedation. Use Caution/Monitor.

• zoledronic acid

  Minor (1)aspirin decreases levels of zoledronic acid by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• zotepine

  Monitor Closely (3)aspirin decreases effects of zotepine by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.
  
  codeine and zotepine both increase sedation. Use Caution/Monitor.
  
  carisoprodol and zotepine both increase sedation. Use Caution/Monitor.