Dosing & Uses
Dosage Forms & Strengths
orphenadrine/aspirin/caffeine
tablet
- 50mg/770mg/60mg
Musculoskeletal Pain
Indicated for symptomatic relief of mild-to-moderate pain caused by acute musculoskeletal disorders as an adjunct to rest, physical therapy, and other measures
0.5-1 tablet (25mg/385mg/30mg to 50mg/770mg/60mg) PO TID/QID
Dosage Forms & Strengths
orphenadrine/aspirin/caffeine
tablet
- 50mg/770mg/60mg
Musculoskeletal Pain
Indicated for symptomatic relief of mild-to-moderate pain caused by acute musculoskeletal disorders as an adjunct to rest, physical therapy, and other measures
<12 years: Safety and efficacy not established
≥12 years: 0.5-1 tablet (25mg/385mg/30mg to 50mg/770mg/60mg) PO TID/QID
Interactions
Interaction Checker
No Results

Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor

Contraindicated (7)
- 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.
- 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.
- fezolinetant
caffeine will increase the level or effect of fezolinetant by affecting hepatic enzyme CYP1A2 metabolism. Contraindicated. Fezolinetant AUC and peak plasma concentration are increased if coadministered with drugs that are weak, moderate, or strong CYP1A2 inhibitors
- isocarboxazid
isocarboxazid increases effects of caffeine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.
- linezolid
linezolid increases effects of caffeine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.
- mifepristone
aspirin, mifepristone. Other (see comment). Contraindicated. Comment: Aspirin induced antiplatelet activity may induce excessive bleeding after an abortion w/mifepristone (RU 486).
- phenelzine
phenelzine increases effects of caffeine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.
Serious - Use Alternative (46)
- 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, orphenadrine. 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 orphenadrine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate - buprenorphine subdermal implant
buprenorphine subdermal implant and orphenadrine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate
- buprenorphine transdermal
buprenorphine transdermal and orphenadrine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate
- buprenorphine, long-acting injection
buprenorphine, long-acting injection and orphenadrine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate
- bupropion
caffeine increases toxicity of bupropion by unspecified interaction mechanism. Avoid or Use Alternate Drug. May lower seizure threshold; keep bupropion dose as low as possible.
- calcium/magnesium/potassium/sodium oxybates
orphenadrine, 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, orphenadrine. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Enhanced CNS depressant effects.
- dipyridamole
caffeine decreases effects of dipyridamole by pharmacodynamic antagonism. Contraindicated.
- 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.
- fedratinib
orphenadrine will increase the level or effect of fedratinib by Other (see comment). Avoid or Use Alternate Drug. Avoid coadministration of fedratinib (a CYP3A4 and CYP2C19 substrate) with dual CYP3A4 and CYP2C19 inhibitor. Effect of coadministration of a dual CYP3A4 and CYP2C19 inhibitor with fedratinib has not been studied.
- fentanyl
fentanyl and orphenadrine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate
- fentanyl intranasal
fentanyl intranasal and orphenadrine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate
- fentanyl iontophoretic transdermal system
fentanyl iontophoretic transdermal system and orphenadrine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate
- fentanyl transdermal
fentanyl transdermal and orphenadrine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate
- 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.
- givosiran
givosiran will increase the level or effect of caffeine by affecting hepatic enzyme CYP1A2 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sensitive CYP1A2 substrates with givosiran. If unavoidable, decrease the CYP1A2 substrate dosage in accordance with approved product labeling.
- glucagon
glucagon increases toxicity of orphenadrine by Other (see comment). Avoid or Use Alternate Drug. Comment: Coadministration of anticholinergic drugs and glucagon increase the risk of gastrointestinal adverse reactions due to additive effects on inhibition of gastrointestinal motility. .
- glucagon intranasal
glucagon intranasal increases toxicity of orphenadrine by Other (see comment). Avoid or Use Alternate Drug. Comment: Coadministration of anticholinergic drugs and glucagon increase the risk of gastrointestinal adverse reactions due to additive effects on inhibition of gastrointestinal motility. .
- hydrocodone
hydrocodone, orphenadrine. 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. - iobenguane I 131
caffeine will decrease the level or effect of iobenguane I 131 by Other (see comment). Avoid or Use Alternate Drug. Based on the mechanism of action of iobenguane, drugs that reduce catecholamine uptake or that deplete catecholamine stores may interfere with iobenguane uptake into cells, and thus, reduce iobenguane efficacy. Discontinue interfering drugs for at least 5 half-lives before administration of either the dosimetry or an iobenguane dose. Do not administer these drugs until at least 7 days after each iobenguane dose.
- 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.
- 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
orphenadrine will increase the level or effect of lonafarnib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of lonafarnib (a sensitive CYP3A substrate) with weak CYP3A inhibitors is unavoidable, reduce to, or continue lonafarnib at starting dose. Closely monitor for arrhythmias and events (eg, syncope, heart palpitations) since lonafarnib effect on QT interval is unknown.
- 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.
- metoclopramide intranasal
orphenadrine, 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.
- olopatadine intranasal
orphenadrine 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 increases toxicity of caffeine by 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.
- 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.
- 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.
- 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.
- regadenoson
caffeine decreases effects of regadenoson by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Avoid methylxanthines for 12 hours before regadenoson administration.
- sodium oxybate
orphenadrine, 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.
Monitor Closely (552)
- 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.
- abobotulinumtoxinA
orphenadrine increases effects of abobotulinumtoxinA by pharmacodynamic synergism. Use Caution/Monitor. Muscle relaxants may enhance botulinum toxin effects. Closely monitor for increased neuromuscular blockade.
abobotulinumtoxinA increases effects of orphenadrine by pharmacodynamic synergism. Use Caution/Monitor. Use of anticholinergic drugs after administration of botulinum toxin-containing products may potentiate systemic anticholinergic effects. - 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). - aclidinium
aclidinium and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- acrivastine
acrivastine and orphenadrine both increase sedation. Use Caution/Monitor.
- agrimony
aspirin and agrimony both increase anticoagulation. Use Caution/Monitor.
- albuterol
aspirin increases and albuterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
albuterol and caffeine both decrease sedation. Use Caution/Monitor. - alfalfa
aspirin and alfalfa both increase anticoagulation. Use Caution/Monitor.
- alfentanil
alfentanil increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- alfentanil
orphenadrine and alfentanil 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 increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
alprazolam and orphenadrine 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.
- amitriptyline
amitriptyline increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- American ginseng
aspirin and American ginseng both increase anticoagulation. Use Caution/Monitor.
- amiloride
amiloride and aspirin both increase serum potassium. Modify Therapy/Monitor Closely.
- amisulpride
amisulpride and orphenadrine both increase sedation. Use Caution/Monitor.
- amitriptyline
amitriptyline and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
orphenadrine and amitriptyline both increase sedation. Use Caution/Monitor. - amobarbital
amobarbital increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
amobarbital and orphenadrine both increase sedation. Use Caution/Monitor. - amoxapine
amoxapine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
amoxapine and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
orphenadrine 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. - arformoterol
arformoterol and caffeine both decrease sedation. 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. - anticholinergic/sedative combos
anticholinergic/sedative combos and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- 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
orphenadrine and apomorphine both increase sedation. Use Caution/Monitor.
- arformoterol
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
aripiprazole increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
orphenadrine and aripiprazole both increase sedation. Use Caution/Monitor. - armodafinil
armodafinil and caffeine both decrease sedation. Use Caution/Monitor.
- asenapine
asenapine and orphenadrine both increase sedation. Use Caution/Monitor.
aspirin decreases effects of asenapine by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis. - asenapine transdermal
asenapine transdermal and orphenadrine 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. - atracurium
atracurium and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- atropine
atropine and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- atropine IV/IM
atropine IV/IM and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- avapritinib
orphenadrine will increase the level or effect of avapritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
avapritinib and orphenadrine both increase sedation. Use Caution/Monitor. - axitinib
orphenadrine increases levels of axitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- azelastine
azelastine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
azelastine and orphenadrine 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. .
- belladonna and opium
belladonna and opium increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- 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 orphenadrine both increase sedation. Use Caution/Monitor.
- belladonna alkaloids
belladonna alkaloids and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- belladonna and opium
belladonna and opium and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
orphenadrine 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
orphenadrine and benperidol both increase sedation. Use Caution/Monitor.
benperidol increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - benzphetamine
orphenadrine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
caffeine and benzphetamine both decrease sedation. Use Caution/Monitor. - benztropine
benztropine and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor. Additive anticholinergic adverse effects may be seen with concurrent use.
- brompheniramine
brompheniramine increases and caffeine 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. - bethanechol
bethanechol increases and orphenadrine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- 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, orphenadrine. Either increases toxicity of the other by sedation. Use Caution/Monitor.
- brexpiprazole
brexpiprazole and orphenadrine both increase sedation. Use Caution/Monitor.
- brimonidine
brimonidine and orphenadrine 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 orphenadrine both increase sedation. Use Caution/Monitor.
- brompheniramine
brompheniramine and orphenadrine 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
orphenadrine and buprenorphine both increase sedation. Use Caution/Monitor.
- buprenorphine buccal
orphenadrine and buprenorphine buccal both increase sedation. Use Caution/Monitor.
buprenorphine buccal increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - buprenorphine, long-acting injection
buprenorphine, long-acting injection increases effects of orphenadrine 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.
- butabarbital
butabarbital increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- butabarbital
butabarbital and orphenadrine both increase sedation. Use Caution/Monitor.
- butalbital
butalbital increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
butalbital and orphenadrine both increase sedation. Use Caution/Monitor. - butorphanol
orphenadrine and butorphanol both increase sedation. Use Caution/Monitor.
butorphanol 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. - carbinoxamine
carbinoxamine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- 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.
- carbachol
carbachol increases and orphenadrine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- carbenoxolone
aspirin increases and carbenoxolone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- carbinoxamine
carbinoxamine and orphenadrine both increase sedation. Use Caution/Monitor.
- carisoprodol
carisoprodol and orphenadrine 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. - cevimeline
cevimeline increases and orphenadrine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- chloral hydrate
chloral hydrate increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
chloral hydrate and orphenadrine both increase sedation. Use Caution/Monitor. - chlordiazepoxide
chlordiazepoxide and orphenadrine both increase sedation. Use Caution/Monitor.
chlordiazepoxide increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - chlorothiazide
aspirin increases and chlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- chlorpheniramine
chlorpheniramine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- chlorpheniramine
chlorpheniramine and orphenadrine both increase sedation. Use Caution/Monitor.
- chlorpromazine
orphenadrine and chlorpromazine both increase sedation. Use Caution/Monitor.
chlorpromazine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - chlorpropamide
aspirin increases effects of chlorpropamide by unknown mechanism. Use Caution/Monitor. Risk of hypoglycemia.
- cinnarizine
cinnarizine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- chlorthalidone
aspirin increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- chlorzoxazone
chlorzoxazone and orphenadrine 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 orphenadrine 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.
ciprofloxacin will increase the level or effect of caffeine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor. The hepatic metabolism of caffeine may be decreased by ciprofloxacin; pharmacologic effects of caffeine may be increased. - cisatracurium
cisatracurium and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- clemastine
clemastine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- 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 orphenadrine both increase sedation. Use Caution/Monitor.
- 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.
clomipramine and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
orphenadrine and clomipramine both increase sedation. Use Caution/Monitor.
clomipramine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - clonazepam
clonazepam and orphenadrine both increase sedation. Use Caution/Monitor.
clonazepam increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. 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 increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- clorazepate
clorazepate and orphenadrine both increase sedation. Use Caution/Monitor.
- clozapine
clozapine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
orphenadrine and clozapine both increase sedation. Use Caution/Monitor. - codeine
orphenadrine and codeine both increase sedation. Use Caution/Monitor.
codeine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. 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).
- cyclizine
cyclizine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- 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 orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
cyclizine and orphenadrine both increase sedation. Use Caution/Monitor. - cyclobenzaprine
cyclobenzaprine and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
cyclobenzaprine and orphenadrine 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 increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
cyproheptadine and orphenadrine 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
- deferasirox
deferasirox increases levels of caffeine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
- 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 orphenadrine both increase sedation. Use Caution/Monitor.
- daridorexant
orphenadrine 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 and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- 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
desipramine and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
orphenadrine and desipramine both increase sedation. Use Caution/Monitor.
desipramine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - 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.
- dexchlorpheniramine
dexchlorpheniramine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. 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 orphenadrine both increase sedation. Use Caution/Monitor.
- dexfenfluramine
caffeine and dexfenfluramine both decrease sedation. Use Caution/Monitor.
orphenadrine increases and dexfenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - dexmedetomidine
dexmedetomidine and orphenadrine both increase sedation. Use Caution/Monitor.
dexmedetomidine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - dexmethylphenidate
caffeine and dexmethylphenidate both decrease sedation. Use Caution/Monitor.
- dextromoramide
orphenadrine and dextromoramide both increase sedation. Use Caution/Monitor.
- dextroamphetamine
caffeine and dextroamphetamine both decrease sedation. Use Caution/Monitor.
- dextromoramide
dextromoramide increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- diamorphine
diamorphine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
orphenadrine and diamorphine both increase sedation. Use Caution/Monitor. - diazepam
diazepam and orphenadrine both increase sedation. Use Caution/Monitor.
- diethylpropion
caffeine and diethylpropion both decrease sedation. Use Caution/Monitor.
- 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.
- dicyclomine
dicyclomine and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- difelikefalin
difelikefalin and orphenadrine both increase sedation. Use Caution/Monitor.
- difenoxin hcl
difenoxin hcl increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
orphenadrine 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. - dimenhydrinate
dimenhydrinate increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- digoxin
aspirin and digoxin both increase serum potassium. Use Caution/Monitor.
- dimenhydrinate
dimenhydrinate and orphenadrine both increase sedation. Use Caution/Monitor.
- diphenhydramine
diphenhydramine and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
diphenhydramine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
diphenhydramine and orphenadrine both increase sedation. Use Caution/Monitor. - diphenoxylate hcl
orphenadrine and diphenoxylate hcl both increase sedation. Use Caution/Monitor.
diphenoxylate hcl increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - dipipanone
orphenadrine and dipipanone both increase sedation. Use Caution/Monitor.
dipipanone increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. 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
dobutamine and caffeine both decrease sedation. Use Caution/Monitor.
- dobutamine
aspirin increases and dobutamine decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- donepezil
donepezil increases and orphenadrine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- dong quai
aspirin and dong quai both increase anticoagulation. Use Caution/Monitor.
- dopamine
caffeine and dopamine both decrease sedation. Use Caution/Monitor.
- dopexamine
aspirin increases and dopexamine decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
dopexamine and caffeine both decrease sedation. Use Caution/Monitor.
orphenadrine increases and dopexamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - dosulepin
orphenadrine and dosulepin both increase sedation. Use Caution/Monitor.
- doxepin
doxepin increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- doxazosin
aspirin decreases effects of doxazosin by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.
- doxepin
doxepin and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
orphenadrine and doxepin both increase sedation. Use Caution/Monitor. - doxylamine
doxylamine and orphenadrine both increase sedation. Use Caution/Monitor.
- droperidol
orphenadrine and droperidol both increase sedation. Use Caution/Monitor.
droperidol increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - drospirenone
drospirenone and aspirin both increase serum potassium. Modify Therapy/Monitor Closely.
- droxidopa
caffeine and droxidopa both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. May increase risk for supine hypertension
- 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.
- echothiophate iodide
echothiophate iodide increases and orphenadrine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- 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.
- 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.
- 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.
- 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.
ephedrine and caffeine both decrease sedation. Use Caution/Monitor. - epinephrine
epinephrine and caffeine both decrease sedation. Use Caution/Monitor.
aspirin increases and epinephrine decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor. - epinephrine inhaled
caffeine, epinephrine inhaled. Either increases effects of the other by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.
- epinephrine racemic
aspirin increases and epinephrine racemic decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- epinephrine racemic
epinephrine racemic and caffeine both decrease sedation. Use Caution/Monitor.
- epoprostenol
aspirin and epoprostenol both increase anticoagulation. Use Caution/Monitor.
- 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.
- esketamine intranasal
esketamine intranasal, orphenadrine. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely.
esketamine intranasal, caffeine. Either increases toxicity of the other by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. Closely monitor blood pressure with concomitant use of esketamine nasal with stimulants. . - 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 increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- estazolam
estazolam and orphenadrine 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
ethanol increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
orphenadrine and ethanol both increase sedation. Use Caution/Monitor. - ethinylestradiol
ethinylestradiol will increase the level or effect of caffeine by affecting hepatic enzyme CYP1A2 metabolism. 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 orphenadrine both increase sedation. Use Caution/Monitor.
- fenbufen
aspirin and fenbufen both increase anticoagulation. Use Caution/Monitor.
aspirin and fenbufen both increase serum potassium. Use Caution/Monitor. - fenfluramine
caffeine and fenfluramine both decrease sedation. Use Caution/Monitor.
orphenadrine 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.
- fexinidazole
fexinidazole will increase the level or effect of caffeine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
- fenoprofen
aspirin and fenoprofen both increase anticoagulation. Use Caution/Monitor.
aspirin and fenoprofen both increase serum potassium. Use Caution/Monitor. - fesoterodine
fesoterodine and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- feverfew
aspirin and feverfew both increase anticoagulation. Use Caution/Monitor.
- finerenone
orphenadrine will increase the level or effect of finerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor serum potassium during initiation and dosage adjustment of either finererone or weak CYP3A4 inhibitors. Adjust finererone dosage as needed.
- 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.
- flavoxate
flavoxate and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- flibanserin
orphenadrine will increase the level or effect of flibanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Increased flibanserin adverse effects may occur if coadministered with multiple weak CYP3A4 inhibitors.
- 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.
- fluphenazine
fluphenazine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
orphenadrine and fluphenazine both increase sedation. Use Caution/Monitor. - flurazepam
flurazepam and orphenadrine both increase sedation. Use Caution/Monitor.
flurazepam increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - flurbiprofen
aspirin and flurbiprofen both increase anticoagulation. Use Caution/Monitor.
aspirin and flurbiprofen both increase serum potassium. Use Caution/Monitor. - fluvoxamine
fluvoxamine will increase the level or effect of caffeine by affecting hepatic enzyme CYP1A2 metabolism. 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
aspirin increases and formoterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
formoterol and caffeine both decrease sedation. Use Caution/Monitor. - forskolin
aspirin and forskolin both increase anticoagulation. Use Caution/Monitor.
- green tea
green tea increases effects of caffeine by Other (see comment). Use Caution/Monitor. Comment: Potential for increased risk of CNS stimulation due to caffeine component of green tea. Caution advised.
- 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.
- furosemide
aspirin increases and furosemide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- galantamine
galantamine increases and orphenadrine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- ganaxolone
orphenadrine and ganaxolone both increase sedation. 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.
- glycopyrrolate
glycopyrrolate and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- glycopyrrolate inhaled
glycopyrrolate inhaled and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- 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.
- guselkumab
guselkumab, caffeine. Other (see comment). Use Caution/Monitor. Comment: Formation of CYP450 enzymes can be altered by increased levels of certain cytokines during chronic inflammation; thus, normalizing the formation of CYP450 enzymes. Upon initiation or discontinuation of guselkumab in patients who are receiving concomitant CYP450 substrates, particularly those with a narrow therapeutic index, consider monitoring for therapeutic effect.
- haloperidol
haloperidol increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
orphenadrine and haloperidol both increase sedation. 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. - hydromorphone
hydromorphone increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- homatropine
homatropine and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- horse chestnut seed
aspirin and horse chestnut seed both increase anticoagulation. Use Caution/Monitor.
- huperzine A
huperzine A increases and orphenadrine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. 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
orphenadrine and hydromorphone both increase sedation. Use Caution/Monitor.
- hydroxyzine
hydroxyzine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
hydroxyzine and orphenadrine both increase sedation. Use Caution/Monitor. - hyoscyamine
hyoscyamine and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- iloperidone
iloperidone increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- hyoscyamine spray
hyoscyamine spray and orphenadrine both decrease cholinergic effects/transmission. 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. Periodically monitor if coadministered with other drugs that affect bleeding.
- iloperidone
orphenadrine 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
orphenadrine and imipramine both increase sedation. Use Caution/Monitor.
imipramine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
imipramine and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor. - incobotulinumtoxinA
orphenadrine, 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.
- isoproterenol
isoproterenol and caffeine both decrease sedation. Use Caution/Monitor.
- 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.
- ipratropium
ipratropium and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- 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. - isavuconazonium sulfate
orphenadrine will increase the level or effect of isavuconazonium sulfate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- isoproterenol
aspirin increases and isoproterenol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- ivacaftor
orphenadrine increases levels of ivacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor when coadministered with weak CYP3A4 inhibitors .
- ketamine
ketamine and orphenadrine 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. - 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
orphenadrine and ketotifen, ophthalmic both increase sedation. Use Caution/Monitor.
ketotifen, ophthalmic increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. 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. - letermovir
letermovir increases levels of caffeine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- 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
orphenadrine will increase the level or effect of lemborexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Lower nightly dose of lemborexant recommended if coadministered with weak CYP3A4 inhibitors. See drug monograph for specific dosage modification.
- levalbuterol
aspirin increases and levalbuterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
levalbuterol and caffeine both decrease sedation. 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
levorphanol increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- levorphanol
orphenadrine and levorphanol both increase sedation. Use Caution/Monitor.
- levothyroxine
caffeine decreases levels of levothyroxine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Caffeine (a sympathomimetic) concomitantly used with oral levothyroxine may increase the effects of sympathomimetics or thyroid hormone. Thyroid hormones may increase the risk of coronary insufficiency when sympathomimetic agents are administered to patients with coronary artery disease.
- lisdexamfetamine
caffeine and lisdexamfetamine both decrease sedation. 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
lofepramine and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
lofepramine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
orphenadrine and lofepramine both increase sedation. Use Caution/Monitor. - lofexidine
orphenadrine and lofexidine both increase sedation. Use Caution/Monitor.
lofexidine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - lomitapide
orphenadrine increases levels of lomitapide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Lomitapide dose should not exceed 30 mg/day.
- loprazolam
loprazolam increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- loprazolam
loprazolam and orphenadrine both increase sedation. Use Caution/Monitor.
- lorazepam
lorazepam increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
lorazepam and orphenadrine both increase sedation. Use Caution/Monitor. - lormetazepam
lormetazepam and orphenadrine both increase sedation. Use Caution/Monitor.
lormetazepam increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - lornoxicam
aspirin and lornoxicam both increase anticoagulation. Use Caution/Monitor.
aspirin and lornoxicam both increase serum potassium. Use Caution/Monitor. - loxapine
loxapine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. 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 inhaled
orphenadrine and loxapine inhaled both increase sedation. Use Caution/Monitor.
loxapine inhaled increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - lurasidone
lurasidone, orphenadrine. 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
maprotiline increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- maprotiline
maprotiline and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
orphenadrine and maprotiline both increase sedation. Use Caution/Monitor. - marijuana
marijuana increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
orphenadrine and marijuana both increase sedation. Use Caution/Monitor. - mavacamten
orphenadrine will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.
- melatonin
melatonin increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- meclizine
meclizine and orphenadrine both decrease cholinergic effects/transmission. 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.
orphenadrine 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
orphenadrine and meperidine both increase sedation. Use Caution/Monitor.
meperidine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - meprobamate
meprobamate increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
orphenadrine 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
metaproterenol and caffeine both decrease sedation. Use Caution/Monitor.
- metaproterenol
aspirin increases and metaproterenol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- metaxalone
metaxalone and orphenadrine both increase sedation. Use Caution/Monitor.
- methadone
orphenadrine and methadone both increase sedation. Use Caution/Monitor.
methadone increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - methamphetamine
caffeine and methamphetamine both decrease 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.
- methocarbamol
methocarbamol and orphenadrine both increase sedation. Use Caution/Monitor.
- methotrexate
caffeine decreases effects of methotrexate by pharmacodynamic antagonism. Use Caution/Monitor.
- methscopolamine
methscopolamine and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- methyclothiazide
aspirin increases and methyclothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor. .
- methylenedioxymethamphetamine
caffeine and methylenedioxymethamphetamine both decrease sedation. Use Caution/Monitor.
orphenadrine increases and methylenedioxymethamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - methylphenidate
caffeine increases effects of methylphenidate by pharmacodynamic synergism. Use Caution/Monitor. Risk of acute hypertensive episode.
- 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 increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
midazolam and orphenadrine both increase sedation. Use Caution/Monitor. - midazolam intranasal
orphenadrine will increase the level or effect of midazolam intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of mild CYP3A4 inhibitors with midazolam intranasal may cause higher midazolam systemic exposure, which may prolong sedation.
midazolam intranasal, orphenadrine. Either increases toxicity 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
caffeine and midodrine both decrease sedation. 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
orphenadrine and mirtazapine both increase sedation. Use Caution/Monitor.
mirtazapine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - mistletoe
aspirin increases and mistletoe decreases anticoagulation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- modafinil
caffeine and modafinil both decrease sedation. 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
orphenadrine and morphine both increase sedation. Use Caution/Monitor.
morphine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - motherwort
orphenadrine and motherwort both increase sedation. Use Caution/Monitor.
motherwort increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - moxisylyte
aspirin decreases effects of moxisylyte by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.
- moxonidine
moxonidine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- moxonidine
orphenadrine 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
orphenadrine and nabilone both increase sedation. Use Caution/Monitor.
nabilone increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - nabumetone
aspirin and nabumetone both increase anticoagulation. Use Caution/Monitor.
aspirin and nabumetone both increase serum potassium. Use Caution/Monitor. - nalbuphine
nalbuphine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. 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
orphenadrine 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.
- neostigmine
neostigmine increases and orphenadrine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- 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
norepinephrine and caffeine both decrease sedation. Use Caution/Monitor.
aspirin increases and norepinephrine decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor. - nortriptyline
nortriptyline and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
orphenadrine and nortriptyline both increase sedation. Use Caution/Monitor.
nortriptyline increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - olanzapine
orphenadrine and olanzapine both increase sedation. Use Caution/Monitor.
olanzapine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - oliceridine
oliceridine, orphenadrine. 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.
orphenadrine 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. - opium tincture
opium tincture increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. 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. - 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. .
- onabotulinumtoxinA
onabotulinumtoxinA and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- opium tincture
orphenadrine and opium tincture 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 increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
oxazepam and orphenadrine both increase sedation. Use Caution/Monitor. - oxybutynin
oxybutynin and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- oxycodone
oxycodone increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- oxybutynin topical
oxybutynin topical and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- oxybutynin transdermal
oxybutynin transdermal and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- oxycodone
orphenadrine and oxycodone both increase sedation. Use Caution/Monitor.
- oxymorphone
oxymorphone increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
orphenadrine and oxymorphone both increase sedation. Use Caution/Monitor. - paliperidone
orphenadrine and paliperidone both increase sedation. Use Caution/Monitor.
paliperidone increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - panax ginseng
aspirin and panax ginseng both increase anticoagulation. Use Caution/Monitor.
- papaveretum
papaveretum increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- pancuronium
pancuronium and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- papaveretum
orphenadrine and papaveretum both increase sedation. Use Caution/Monitor.
- papaverine
orphenadrine 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.
- pau d'arco
aspirin and pau d'arco both increase anticoagulation. Use Caution/Monitor.
- pefloxacin
pefloxacin will increase the level or effect of caffeine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
- pegaspargase
pegaspargase increases effects of aspirin by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of bleeding events.
- 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. - pentazocine
orphenadrine and pentazocine both increase sedation. Use Caution/Monitor.
pentazocine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - pentobarbital
pentobarbital and orphenadrine both increase sedation. Use Caution/Monitor.
pentobarbital increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. 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
perphenazine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- perphenazine
orphenadrine and perphenazine both increase sedation. Use Caution/Monitor.
- phendimetrazine
caffeine and phendimetrazine both decrease sedation. Use Caution/Monitor.
- phenindione
phenindione and aspirin both increase anticoagulation. Modify Therapy/Monitor Closely.
- phenobarbital
phenobarbital increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
phenobarbital and orphenadrine both increase sedation. Use Caution/Monitor. - phenoxybenzamine
aspirin decreases effects of phenoxybenzamine by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.
- phentermine
caffeine and phentermine both decrease sedation. Use Caution/Monitor.
- phentolamine
aspirin decreases effects of phentolamine by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.
- phenylephrine
caffeine and phenylephrine both decrease sedation. Use Caution/Monitor.
- phenylephrine PO
caffeine and phenylephrine PO both decrease sedation. Use Caution/Monitor.
orphenadrine increases and phenylephrine PO decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. . - pholcodine
pholcodine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
orphenadrine and pholcodine both increase sedation. Use Caution/Monitor. - physostigmine
physostigmine increases and orphenadrine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- pimozide
pimozide increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- phytoestrogens
aspirin and phytoestrogens both increase anticoagulation. Use Caution/Monitor.
- pilocarpine
pilocarpine increases and orphenadrine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- pimozide
orphenadrine 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.
pirbuterol and caffeine both decrease sedation. Use Caution/Monitor. - piroxicam
aspirin and piroxicam both increase anticoagulation. Use Caution/Monitor.
aspirin and piroxicam both increase serum potassium. Use Caution/Monitor. - primidone
primidone increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- 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.
- prabotulinumtoxinA
orphenadrine increases effects of prabotulinumtoxinA by pharmacodynamic synergism. Use Caution/Monitor. Muscle relaxants may enhance botulinum toxin effects. Closely monitor for increased neuromuscular blockade.
- pralidoxime
pralidoxime and orphenadrine both decrease cholinergic effects/transmission. 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.
- primidone
primidone and orphenadrine both increase sedation. Use Caution/Monitor.
- prochlorperazine
orphenadrine and prochlorperazine both increase sedation. Use Caution/Monitor.
prochlorperazine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - promethazine
promethazine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
promethazine and orphenadrine both increase sedation. Use Caution/Monitor. - propantheline
propantheline and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- propylhexedrine
caffeine and propylhexedrine both decrease sedation. Use Caution/Monitor.
- propofol
propofol and orphenadrine 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
orphenadrine 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
protriptyline and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
orphenadrine and protriptyline both increase sedation. Use Caution/Monitor.
protriptyline increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - pyridostigmine
pyridostigmine increases and orphenadrine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- quazepam
quazepam increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- quazepam
quazepam and orphenadrine both increase sedation. Use Caution/Monitor.
- quetiapine
quetiapine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
orphenadrine 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.
- rasagiline
rasagiline increases effects of caffeine by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Risk of acute hypertensive episode.
- ramelteon
orphenadrine 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.
- rapacuronium
rapacuronium and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- reishi
aspirin and reishi both increase anticoagulation. Use Caution/Monitor.
- remimazolam
remimazolam, orphenadrine. 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.
- risperidone
orphenadrine and risperidone both increase sedation. Use Caution/Monitor.
risperidone increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - 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.
- rucaparib
rucaparib will increase the level or effect of caffeine by affecting hepatic enzyme CYP1A2 metabolism. Modify Therapy/Monitor Closely. Adjust dosage of CYP1A2 substrates, if clinically indicated.
- rivastigmine
rivastigmine increases toxicity of aspirin by pharmacodynamic synergism. Use Caution/Monitor. Monitor patients for symptoms of active or occult gastrointestinal bleeding.
- rocuronium
rocuronium and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- 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
aspirin increases and salmeterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
salmeterol and caffeine both decrease sedation. Use Caution/Monitor. - salsalate
aspirin and salsalate both increase anticoagulation. Use Caution/Monitor.
aspirin and salsalate both increase serum potassium. Use Caution/Monitor. - scullcap
scullcap increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- saw palmetto
saw palmetto increases toxicity of aspirin by unspecified interaction mechanism. Use Caution/Monitor. May increase risk of bleeding.
- scopolamine
scopolamine and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- scullcap
orphenadrine and scullcap both increase sedation. Use Caution/Monitor.
- secobarbital
secobarbital increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
secobarbital and orphenadrine both increase sedation. Use Caution/Monitor. - selegiline
selegiline increases effects of caffeine by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Risk of acute hypertensive episode.
- 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
shepherd's purse increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
orphenadrine 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.
- solriamfetol
caffeine and solriamfetol both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.
- 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.
- solifenacin
solifenacin and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- 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
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, caffeine. affecting hepatic enzyme CYP1A2 metabolism. Modify Therapy/Monitor Closely. Stiripentol is a CYP1A2 inhibitor and inducer. Monitor CYP1A2 substrates coadministered with stiripentol for increased or decreased effects. CYP1A2 substrates may require dosage adjustment.
stiripentol, orphenadrine. 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. - succinylcholine
aspirin and succinylcholine both increase serum potassium. Use Caution/Monitor.
succinylcholine increases and orphenadrine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor. - sufentanil
sufentanil increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- sufentanil
orphenadrine 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. - 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
orphenadrine and tapentadol both increase sedation. Use Caution/Monitor.
tapentadol increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - tazemetostat
orphenadrine will increase the level or effect of tazemetostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- temazepam
temazepam increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- 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 orphenadrine 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.
- terbutaline
terbutaline and caffeine both decrease sedation. Use Caution/Monitor.
aspirin increases and terbutaline decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor. - teriflunomide
teriflunomide decreases levels of caffeine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
- thioridazine
orphenadrine and thioridazine both increase sedation. Use Caution/Monitor.
- thioridazine
thioridazine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- thiothixene
orphenadrine and thiothixene both increase sedation. Use Caution/Monitor.
thiothixene increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. 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.
- topiramate
topiramate increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Modify Therapy/Monitor Closely.
- 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. - 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. - tinidazole
orphenadrine will increase the level or effect of tinidazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- tiotropium
tiotropium and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- 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. - tolterodine
tolterodine and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- tolvaptan
aspirin and tolvaptan both increase serum potassium. Use Caution/Monitor.
- topiramate
orphenadrine 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
tramadol increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
orphenadrine 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.
- trazodone
trazodone increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- 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.
trazodone and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
orphenadrine 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.
- triazolam
triazolam increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
triazolam and orphenadrine both increase sedation. Use Caution/Monitor. - triamterene
triamterene and aspirin both increase serum potassium. Modify Therapy/Monitor Closely.
- triclofos
triclofos increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- triclofos
triclofos and orphenadrine both increase sedation. Use Caution/Monitor.
- trifluoperazine
orphenadrine and trifluoperazine both increase sedation. Use Caution/Monitor.
trifluoperazine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - trihexyphenidyl
trihexyphenidyl and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor. Potential for additive anticholinergic effects.
- trimipramine
trimipramine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- trimipramine
trimipramine and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
orphenadrine and trimipramine both increase sedation. Use Caution/Monitor. - triprolidine
triprolidine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- trospium chloride
trospium chloride and orphenadrine both decrease cholinergic effects/transmission. 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. - vecuronium
vecuronium and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- 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
caffeine and xylometazoline both decrease sedation. Use Caution/Monitor.
orphenadrine increases and xylometazoline decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - yohimbine
caffeine and yohimbine both decrease sedation. 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
orphenadrine and ziconotide both increase sedation. Use Caution/Monitor.
ziconotide increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - ziprasidone
orphenadrine and ziprasidone both increase sedation. Use Caution/Monitor.
ziprasidone increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - zotepine
aspirin decreases effects of zotepine by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.
orphenadrine and zotepine both increase sedation. Use Caution/Monitor.
Minor (132)
- 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.
- adenosine
caffeine decreases effects of adenosine by pharmacodynamic antagonism. 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).
- amantadine
amantadine, caffeine. Either increases effects of the other by pharmacodynamic synergism. Minor/Significance Unknown. Potential for additive CNS stimulation.
- American ginseng
American ginseng increases effects of caffeine by pharmacodynamic synergism. Minor/Significance Unknown.
- 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.
- amobarbital
amobarbital will decrease the level or effect of caffeine by affecting hepatic enzyme CYP1A2 metabolism. 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.
- armodafinil
armodafinil will decrease the level or effect of caffeine by affecting hepatic enzyme CYP1A2 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. - 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.
- bumetanide
aspirin, bumetanide. Other (see comment). Minor/Significance Unknown. Comment: Salicylates are less likely than other NSAIDs to interact w/bumetanide.
- butabarbital
butabarbital will decrease the level or effect of caffeine by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.
- butalbital
butalbital will decrease the level or effect of caffeine by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.
- calcium acetate
caffeine decreases levels of calcium acetate by increasing renal clearance. Minor/Significance Unknown.
- 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).
caffeine decreases levels of calcium carbonate by increasing renal clearance. Minor/Significance Unknown. - calcium chloride
caffeine decreases levels of calcium chloride by increasing renal clearance. Minor/Significance Unknown.
- cefadroxil
cefadroxil will increase the level or effect of aspirin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- calcium citrate
caffeine decreases levels of calcium citrate by increasing renal clearance. Minor/Significance Unknown.
- calcium gluconate
caffeine decreases levels of calcium gluconate by increasing renal clearance. Minor/Significance Unknown.
- carbamazepine
carbamazepine will decrease the level or effect of caffeine by affecting hepatic enzyme CYP1A2 metabolism. 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.
- chlorpromazine
orphenadrine decreases levels of chlorpromazine by unknown mechanism. Minor/Significance Unknown. Excessive anticholinergic effects and/or hypoglycemia possible.
- 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.
- cigarette smoking
cigarette smoking will decrease the level or effect of caffeine by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.
- cimetidine
cimetidine will increase the level or effect of caffeine by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.
- clotrimazole
clotrimazole increases levels of caffeine by decreasing metabolism. 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.
- 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
eucalyptus increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Minor/Significance Unknown.
orphenadrine 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.
- fluconazole
fluconazole increases levels of caffeine by decreasing metabolism. 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.
- 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.
- grapefruit
grapefruit increases levels of caffeine by decreasing metabolism. Minor/Significance Unknown.
- guarana
guarana increases effects of caffeine by pharmacodynamic synergism. Minor/Significance Unknown.
- 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.
- itraconazole
itraconazole increases levels of caffeine by decreasing metabolism. Minor/Significance Unknown.
- ketoconazole
ketoconazole increases levels of caffeine by decreasing metabolism. 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
levoketoconazole increases levels of caffeine by decreasing metabolism. Minor/Significance Unknown.
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.
- mexiletine
mexiletine will increase the level or effect of caffeine by affecting hepatic enzyme CYP1A2 metabolism. 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.
- miconazole vaginal
miconazole vaginal increases levels of caffeine by decreasing metabolism. 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.
- peginterferon alfa 2a
peginterferon alfa 2a will increase the level or effect of caffeine by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.
- 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.
- pentobarbital
pentobarbital will decrease the level or effect of caffeine by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.
- phenobarbital
phenobarbital will decrease the level or effect of caffeine by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.
- pipemidic acid
pipemidic acid will increase the level or effect of caffeine by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.
- 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.
- posaconazole
posaconazole increases levels of caffeine by decreasing metabolism. 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.
- primidone
primidone will decrease the level or effect of caffeine by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.
- rifampin
rifampin will decrease the level or effect of caffeine by affecting hepatic enzyme CYP1A2 metabolism. 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. - ruxolitinib
orphenadrine will increase the level or effect of ruxolitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- ruxolitinib topical
orphenadrine will increase the level or effect of ruxolitinib topical by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- sage
sage increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Minor/Significance Unknown.
orphenadrine 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.
- secobarbital
secobarbital will decrease the level or effect of caffeine by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.
- smoking
smoking will decrease the level or effect of caffeine by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.
Adverse Effects
Frequency Not Defined
Tachycardia
Palpitation
Urinary hesitancy or retention
Dry mouth
Blurred vision
Dilated pupils
Increased intraocular tension
Weakness
Nausea
Vomiting
Headache
Dizziness
Constipation
Drowsiness
Urticaria (rare)
Other dermatosis (rare)
Confusion in elderly individuals (infrequent)
Mild central excitation and occasional hallucinations
Aplastic anemia (single case)
Gastrointestinal hemorrhage (rare)
Transient episodes of light-headedness, dizziness, or syncope
Warnings
Contraindications
Glaucoma
Pyloric or duodenal obstruction
Achalasia
Prostatic hypertrophy or bladder neck obstructions
Myasthenia gravis
Hypersensitivity to orphenadrine, aspirin, or caffeine
Cautions
Not recommended for use in patients with chicken pox, influenza, or flu symptoms; Reye syndrome may develop in individuals who have chicken pox, influenza, or flu symptoms; studies suggest association between Reye syndrome and use of medicines containing salicylate or aspirin
May impair patient’s ability to engage in potentially hazardous activities (eg, operating machinery, driving a motor vehicle)
Aspirin should be used with extreme caution in the presence of peptic ulcers and coagulation abnormalities
Safety of continuous long term therapy has not been established; therefore, if prescribed for prolonged use, periodic monitoring recommended of blood, urine, and liver function values
Mild adverse effects may respond to dose reduction
Drug reaction with eosinophilia and systemic symptoms
- Drug Reaction reported in patients taking NSAIDs; some of these events have been fatal or life-threatening; DRESS typically, although not exclusively, presents with fever, rash, lymphadenopathy, and/or facial swelling
- Other clinical manifestations may include hepatitis, nephritis, hematological abnormalities, myocarditis, or myositis; sometimes symptoms of DRESS may resemble an acute viral infection
- Eosinophilia is often present; because this disorder is variable in its presentation, other organ systems not noted here may be involved
- Early manifestations of hypersensitivity, such as fever or lymphadenopathy, may be present even though rash is not evident; if such signs or symptoms are present, discontinue therapy and evaluate the patient immediately
Pregnancy & Lactation
Pregnancy
Use of NSAIDs can cause premature closure of fetal ductus arteriosus and fetal renal dysfunction leading to oligohydramnios and, in some cases, neonatal renal impairment
Because of these risks, limit dose and duration of drug combination between about 20 and 30 weeks of gestation, and avoid use at about 30 weeks of gestation and later in pregnancy
Use of NSAIDs at about 20 weeks gestation or later in pregnancy has been associated with cases of fetal renal dysfunction leading to oligohydramnios, and in some cases, neonatal renal impairment
If an NSAID is necessary at about 20 weeks gestation or later in pregnancy, limit use to the lowest effective dose and shortest duration possible; if drug combination treatment extends beyond 48 hours, consider monitoring with ultrasound for oligohydramnios; if oligohydramnios occurs, discontinue drug use and follow up according to clinical practice
If an NSAID is necessary at about 20 weeks gestation or later in pregnancy, limit the use to the lowest effective dose and shortest duration possible. If treatment extends beyond 48 hours, consider monitoring with ultrasound for oligohydramnios. If oligohydramnios occurs, discontinue treatment and follow up according to clinical practice
Data from observational studies regarding other potential embryofetal risks of NSAID use in women in the first or second trimesters of pregnancy are inconclusive
Animal data
- Based on animal data, prostaglandins have been shown to have important role in endometrial vascular permeability, blastocyst implantation, and decidualization; in animal studies, administration of prostaglandin synthesis inhibitors such as aspirin, resulted in increased pre-and post-implantation loss
- Prostaglandins also have been shown to have an important role in fetal kidney development; in published animal studies, prostaglandin synthesis inhibitors have been reported to impair kidney development when administered at clinically relevant doses
Lactation
Safety during lactation has not been established
Pregnancy Categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk. C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done. D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk. X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist. NA: Information not available.Pharmacology
Mechanism of Action
Orphenadrine: Indirect skeletal muscle relaxant; exact mechanism unknown, but may antagonize N-methyl-D-aspartate (NMDA) receptors
Aspirin: Inhibits synthesis of prostaglandin by cyclooxygenase; has antiinflammatory and analgesic activity
Caffeine: Mild, direct stimulant effect of the CNS, heart, and cardiovascular system; stimulates the respiratory center of the medulla
Administration
Oral Administration
May take with or without food
Storage
Store below 30ºC (86ºF)
Images
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