acetaminophen/dextromethorphan/pseudoephedrine/guaifenesin (OTC)

Symptomatic Relief of Cough & Congestion

2 tablets PO q6hr; not to exceed 8 tablets/day

Symptomatic Relief of Cough & Congestion

<12 Years Old

• Not recommended

>12 Years Old

• 2 tablets PO q6hr; not to exceed 8 tablets/day

Contraindicated (15)

• dihydroergotamine

  dihydroergotamine increases effects of pseudoephedrine by pharmacodynamic synergism. Contraindicated. Ergot derivatives may enhance the vasoconstricting effect of pseudoephedrine and eventually significantly increasing blood pressure.

• dihydroergotamine inhaled

  dihydroergotamine inhaled increases effects of pseudoephedrine by pharmacodynamic synergism. Contraindicated. Ergot derivatives may enhance the vasoconstricting effect of pseudoephedrine and eventually significantly increasing blood pressure.

• dihydroergotamine intranasal

  dihydroergotamine intranasal increases effects of pseudoephedrine by pharmacodynamic synergism. Contraindicated. Ergot derivatives may enhance the vasoconstricting effect of pseudoephedrine and eventually significantly increasing blood pressure.

• ergoloid mesylates

  ergoloid mesylates increases effects of pseudoephedrine by pharmacodynamic synergism. Contraindicated. Ergot derivatives may enhance the vasoconstricting effect of pseudoephedrine and eventually significantly increasing blood pressure.

• ergonovine

  ergonovine increases effects of pseudoephedrine by pharmacodynamic synergism. Contraindicated. Ergot derivatives may enhance the vasoconstricting effect of pseudoephedrine and eventually significantly increasing blood pressure.

• ergotamine

  ergotamine increases effects of pseudoephedrine by pharmacodynamic synergism. Contraindicated. Ergot derivatives may enhance the vasoconstricting effect of pseudoephedrine and eventually significantly increasing blood pressure.

• isocarboxazid

  isocarboxazid increases effects of pseudoephedrine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.

• linezolid

  linezolid increases effects of pseudoephedrine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.

• methylergonovine

  methylergonovine increases effects of pseudoephedrine by pharmacodynamic synergism. Contraindicated. Ergot derivatives may enhance the vasoconstricting effect of pseudoephedrine and eventually significantly increasing blood pressure.

• phenelzine

  phenelzine increases effects of pseudoephedrine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.

• procarbazine

  procarbazine increases effects of pseudoephedrine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.

• rasagiline

  rasagiline increases effects of pseudoephedrine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.

• selegiline

  selegiline increases effects of pseudoephedrine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.

• selegiline transdermal

  selegiline transdermal increases effects of pseudoephedrine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.

• tranylcypromine

  tranylcypromine increases effects of pseudoephedrine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.

Serious - Use Alternative (25)

• amitriptyline

  amitriptyline increases effects of pseudoephedrine by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Avoid or Use Alternate Drug. Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.

• amoxapine

  amoxapine increases effects of pseudoephedrine by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Avoid or Use Alternate Drug. Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.

• cabergoline

  cabergoline, pseudoephedrine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension.

• clomipramine

  clomipramine increases effects of pseudoephedrine by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Avoid or Use Alternate Drug. Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.

• cocaine topical

  cocaine topical increases effects of pseudoephedrine by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Avoid or Use Alternate Drug.

• desipramine

  desipramine increases effects of pseudoephedrine by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Avoid or Use Alternate Drug. Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.

• desvenlafaxine

  desvenlafaxine increases effects of pseudoephedrine by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Avoid or Use Alternate Drug.

• doxapram

  doxapram increases effects of pseudoephedrine by pharmacodynamic synergism. Avoid or Use Alternate Drug. Additive pressor effect.

• doxepin

  doxepin increases effects of pseudoephedrine by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Avoid or Use Alternate Drug. Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.

• duloxetine

  duloxetine increases effects of pseudoephedrine by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Avoid or Use Alternate Drug.

• imipramine

  imipramine increases effects of pseudoephedrine by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Avoid or Use Alternate Drug. Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.

• iobenguane I 123

  pseudoephedrine decreases effects of iobenguane I 123 by receptor binding competition. Avoid or Use Alternate Drug. If clinically appropriate, discontinue drugs that compete for NE receptor sites for at least 5 half-lives; may cause false-negative imaging results. Do not administer pseudoephedrine until at least 7 days after each iobenguane dose.

• iobenguane I 131

  pseudoephedrine decreases effects of iobenguane I 131 by receptor binding competition. Avoid or Use Alternate Drug. If clinically appropriate, discontinue drugs that compete for NE receptor sites for at least 5 half-lives; may cause false-negative imaging results. Do not administer pseudoephedrine until at least 7 days after each iobenguane dose.

• isoflurane

  isoflurane increases toxicity of pseudoephedrine by Mechanism: unknown. Avoid or Use Alternate Drug. Risk of V tach, HTN.

• levomilnacipran

  levomilnacipran increases effects of pseudoephedrine by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Avoid or Use Alternate Drug.

• lofepramine

  lofepramine, pseudoephedrine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.

• lonafarnib

  acetaminophen 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.

• maprotiline

  maprotiline, pseudoephedrine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.

• methoxyflurane

  methoxyflurane increases toxicity of pseudoephedrine by Mechanism: unknown. Avoid or Use Alternate Drug. Risk of V tach, HTN.

• milnacipran

  milnacipran increases effects of pseudoephedrine by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Avoid or Use Alternate Drug.

• nortriptyline

  nortriptyline increases effects of pseudoephedrine by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Avoid or Use Alternate Drug. Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.

• ozanimod

  ozanimod increases toxicity of pseudoephedrine 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.

• pexidartinib

  acetaminophen and pexidartinib both increase Other (see comment). Avoid or Use Alternate Drug. Pexidartinib can cause hepatotoxicity. Avoid coadministration of pexidartinib with other products know to cause hepatoxicity.

• pretomanid

  acetaminophen, pretomanid. Either increases toxicity of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Pretomanid regimen associated with hepatotoxicity. Avoid alcohol and hepatotoxic agents, including herbal supplements and drugs other than bedaquiline and linezolid.

• protriptyline

  protriptyline increases effects of pseudoephedrine by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Avoid or Use Alternate Drug. Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.

Monitor Closely (99)

• acetazolamide

  acetazolamide will increase the level or effect of pseudoephedrine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

• albuterol

  albuterol and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• alfuzosin

  pseudoephedrine decreases effects of alfuzosin by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• aluminum hydroxide

  aluminum hydroxide will increase the level or effect of pseudoephedrine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor. Caution advised with frequent or high dose antacids

• ammonium chloride

  ammonium chloride decreases effects of pseudoephedrine by unknown mechanism. Use Caution/Monitor. Urinary excretion of indirect acting alpha/beta agonists (eg, pseudoephedrine) may increase when administered concomitantly with urinary acidifying agents, resulting in lower serum concentrations.

• apalutamide

  apalutamide will decrease the level or effect of acetaminophen by increasing elimination. Use Caution/Monitor. Apalutamide induces UGT and may decrease systemic exposure of drugs that are UGT substrates.

• arformoterol

  arformoterol and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• atogepant

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

• avapritinib

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

• axitinib

  acetaminophen increases levels of axitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• benzphetamine

  benzphetamine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• bromocriptine

  bromocriptine, pseudoephedrine. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Hypertension, V tach.

• bupivacaine implant

  acetaminophen, bupivacaine implant. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Local anesthetics may increase the risk of developing methemoglobinemia when concurrently exposed to drugs that also cause methemoglobinemia.

• busulfan

  acetaminophen increases levels of busulfan by decreasing metabolism. Use Caution/Monitor. Use of acetaminophen prior to (< 72 hours) or concurrently with busulfan may result in decreased clearance of busulfan due to acetaminophen-induced decreases in glutathione levels.

• chlorpromazine

  chlorpromazine, pseudoephedrine. Mechanism: unknown. Use Caution/Monitor. Consider avoiding use of pseudoephedrine in patients receiving phenothiazines (especially thioridazine) due to the potential risk of cardiac arrhythmia or sudden death. Monitor for evidence of ventricular arrhythmias during concomitant use.

• dapsone topical

  acetaminophen increases toxicity of dapsone topical by altering metabolism. Modify Therapy/Monitor Closely. May induce methemoglobinemia .

• dexfenfluramine

  dexfenfluramine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• dexmethylphenidate

  dexmethylphenidate and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• dextroamphetamine

  dextroamphetamine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• diethylpropion

  diethylpropion and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• dobutamine

  dobutamine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• dopamine

  dopamine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• dopexamine

  dopexamine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• doxazosin

  pseudoephedrine decreases effects of doxazosin by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• droxidopa

  pseudoephedrine and droxidopa both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. May increase risk for supine hypertension

• eltrombopag

  eltrombopag increases levels of acetaminophen by decreasing metabolism. Use Caution/Monitor. UGT inhibition; significance of interaction unclear.

• ephedrine

  ephedrine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.
  
  ephedrine, pseudoephedrine. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor.

• epinephrine

  epinephrine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• epinephrine inhaled

  pseudoephedrine, epinephrine inhaled. Either increases effects of the other by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• epinephrine racemic

  epinephrine racemic and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• esketamine intranasal

  esketamine intranasal, pseudoephedrine. 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. .

• exenatide injectable solution

  exenatide injectable solution will decrease the level or effect of acetaminophen by unspecified interaction mechanism. Use Caution/Monitor. To avoid potential interaction, give acetaminophen at least 1 hour before or 4 hours after exenatide injection.

• exenatide injectable suspension

  exenatide injectable suspension will decrease the level or effect of acetaminophen by unspecified interaction mechanism. Use Caution/Monitor. To avoid potential interaction, give acetaminophen at least 1 hour before or 4 hours after exenatide injection.

• fenfluramine

  fenfluramine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• finerenone

  acetaminophen 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 moderate CYP3A4 inhibitors. Adjust finererone dosage as needed.

• flibanserin

  acetaminophen 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.

• fluphenazine

  fluphenazine, pseudoephedrine. Mechanism: unknown. Use Caution/Monitor. Consider avoiding use of pseudoephedrine in patients receiving phenothiazines (especially thioridazine) due to the potential risk of cardiac arrhythmia or sudden death. Monitor for evidence of ventricular arrhythmias during concomitant use.

• formoterol

  formoterol and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• hydralazine

  hydralazine, pseudoephedrine. Mechanism: pharmacodynamic antagonism. Use Caution/Monitor. Sympathomimetics can antagonize the activity of some antihypertensive agents.

• imatinib

  imatinib decreases levels of acetaminophen by decreasing hepatic clearance. Modify Therapy/Monitor Closely. In vitro, imatinib was found to inhibit acetaminophen O-glucuronidation (Ki value of 58.5 micro-M) at therapeutic levels; avoid chronic acetaminophen therapy with imatinib; if occasional acetaminophen administered, do not exceed 1300 mg/day.

• insulin degludec

  pseudoephedrine decreases effects of insulin degludec by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. Sympathomimetics increase blood glucose by stimulating alpha and beta receptors; this action results in increased hepatic glucose production, glycogenolysis, and decreased insulin secretion.

• insulin degludec/insulin aspart

  pseudoephedrine decreases effects of insulin degludec/insulin aspart by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. Sympathomimetics increase blood glucose by stimulating alpha and beta receptors; this action results in increased hepatic glucose production, glycogenolysis, and decreased insulin secretion.

• insulin detemir

  pseudoephedrine decreases effects of insulin detemir by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. Sympathomimetics increase blood glucose by stimulating alpha and beta receptors; this action results in increased hepatic glucose production, glycogenolysis, and decreased insulin secretion.

• insulin glargine

  pseudoephedrine decreases effects of insulin glargine by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. Sympathomimetics increase blood glucose by stimulating alpha and beta receptors; this action results in increased hepatic glucose production, glycogenolysis, and decreased insulin secretion.

• insulin inhaled

  pseudoephedrine decreases effects of insulin inhaled by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. Sympathomimetics increase blood glucose by stimulating alpha and beta receptors; this action results in increased hepatic glucose production, glycogenolysis, and decreased insulin secretion.

• insulin regular human

  pseudoephedrine decreases effects of insulin regular human by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. Sympathomimetics increase blood glucose by stimulating alpha and beta receptors; this action results in increased hepatic glucose production, glycogenolysis, and decreased insulin secretion.

• isavuconazonium sulfate

  acetaminophen will increase the level or effect of isavuconazonium sulfate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• isoniazid

  isoniazid will increase the level or effect of acetaminophen by affecting hepatic enzyme CYP2E1 metabolism. Use Caution/Monitor.

• isoproterenol

  isoproterenol and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• ivacaftor

  acetaminophen increases levels of ivacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor when coadministered with weak CYP3A4 inhibitors .

• lemborexant

  acetaminophen 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

  levalbuterol and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• levonorgestrel oral/ethinylestradiol/ferrous bisglycinate

  levonorgestrel oral/ethinylestradiol/ferrous bisglycinate will decrease the level or effect of acetaminophen by unknown mechanism. Use Caution/Monitor.
  
  acetaminophen increases levels of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by decreasing hepatic clearance. Use Caution/Monitor. Coadministration of ascorbic acid and certain combined hormonal contraceptives (CHCs) containing EE may increase plasma EE concentrations, possibly by inhibition of conjugation.

• lisdexamfetamine

  lisdexamfetamine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• lixisenatide (DSC)

  lixisenatide (DSC) will decrease the level or effect of acetaminophen by inhibition of GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. GLP1 agonists delay gastric emptying, which may affect absorption of concomitantly administered oral medications. No effects on acetaminophen Cmax and Tmax were observed when acetaminophen was administered 1 hr before lixisenatide. When administered 1 or 4 hr after lixisenatide, acetaminophen Cmax was decreased by 29% and 31% respectively and median Tmax was delayed by 2 and 1.75 hr, respectively.

• lomitapide

  acetaminophen increases levels of lomitapide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Lomitapide dose should not exceed 30 mg/day.

• metaproterenol

  metaproterenol and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• methamphetamine

  methamphetamine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• methenamine

  methenamine decreases effects of pseudoephedrine by unknown mechanism. Use Caution/Monitor. Urinary excretion of indirect acting alpha/beta agonists (eg, pseudoephedrine) may increase when administered concomitantly with urinary acidifying agents, resulting in lower serum concentrations.

• methyldopa

  methyldopa increases effects of pseudoephedrine by unknown mechanism. Use Caution/Monitor.

• methylenedioxymethamphetamine

  methylenedioxymethamphetamine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• midazolam intranasal

  acetaminophen 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.

• midodrine

  midodrine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• mipomersen

  mipomersen, acetaminophen. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Both drugs have potential to increase hepatic enzymes; monitor LFTs.

• nateglinide

  pseudoephedrine decreases effects of nateglinide by pharmacodynamic antagonism. Use Caution/Monitor. Coadministration may reduce nateglinide's hypoglycemic action.

• norepinephrine

  norepinephrine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• olodaterol inhaled

  pseudoephedrine and olodaterol inhaled both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. Caution with coadministration of adrenergic drugs by any route because of additive sympathetic effects

• oxytocin

  oxytocin increases effects of pseudoephedrine by pharmacodynamic synergism. Use Caution/Monitor.

• perphenazine

  perphenazine, pseudoephedrine. Mechanism: unknown. Use Caution/Monitor. Consider avoiding use of pseudoephedrine in patients receiving phenothiazines (especially thioridazine) due to the potential risk of cardiac arrhythmia or sudden death. Monitor for evidence of ventricular arrhythmias during concomitant use.

• phendimetrazine

  phendimetrazine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• phentermine

  phentermine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• phenylephrine

  phenylephrine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• phenylephrine PO

  phenylephrine PO and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• pirbuterol

  pirbuterol and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• potassium phosphate

  potassium phosphate decreases effects of pseudoephedrine by unknown mechanism. Use Caution/Monitor. Urinary excretion of indirect acting alpha/beta agonists (eg, pseudoephedrine) may increase when administered concomitantly with urinary acidifying agents, resulting in lower serum concentrations.

• prochlorperazine

  prochlorperazine, pseudoephedrine. Mechanism: unknown. Use Caution/Monitor. Consider avoiding use of pseudoephedrine in patients receiving phenothiazines (especially thioridazine) due to the potential risk of cardiac arrhythmia or sudden death. Monitor for evidence of ventricular arrhythmias during concomitant use.

• promazine

  promazine, pseudoephedrine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.

• promethazine

  promethazine, pseudoephedrine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.

• propylhexedrine

  propylhexedrine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• safinamide

  pseudoephedrine and safinamide both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. Monitor patients for hypertension if safinamide is prescribed concomitantly with prescription or nonprescription sympathomimetics, including nasal, oral, or ophthalmic decongestants and cold remedies.

• salmeterol

  salmeterol and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• serdexmethylphenidate/dexmethylphenidate

  serdexmethylphenidate/dexmethylphenidate and pseudoephedrine both decrease sedation. Use Caution/Monitor.
  
  serdexmethylphenidate/dexmethylphenidate and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• silodosin

  pseudoephedrine decreases effects of silodosin by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• sodium bicarbonate

  sodium bicarbonate will increase the level or effect of pseudoephedrine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor. Caution advised with frequent or high dose antacids

• sodium citrate/citric acid

  sodium citrate/citric acid will increase the level or effect of pseudoephedrine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

• sodium lactate

  sodium lactate will increase the level or effect of pseudoephedrine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

• sodium phosphates, IV

  sodium phosphates, IV decreases effects of pseudoephedrine by unknown mechanism. Use Caution/Monitor. Urinary excretion of indirect acting alpha/beta agonists (eg, pseudoephedrine) may increase when administered concomitantly with urinary acidifying agents, resulting in lower serum concentrations.

• solriamfetol

  pseudoephedrine and solriamfetol both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• spironolactone

  spironolactone decreases effects of pseudoephedrine by pharmacodynamic antagonism. Use Caution/Monitor.

• tamsulosin

  pseudoephedrine decreases effects of tamsulosin by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• tazemetostat

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

• terazosin

  pseudoephedrine decreases effects of terazosin by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• terbutaline

  terbutaline and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• tetracaine

  tetracaine, acetaminophen. Other (see comment). Use Caution/Monitor. Comment: Monitor for signs of methemoglobinemia when methemoglobin-inducing drugs are coadministered.

• thioridazine

  thioridazine, pseudoephedrine. Mechanism: unknown. Use Caution/Monitor. Consider avoiding use of pseudoephedrine in patients receiving phenothiazines (especially thioridazine) due to the potential risk of cardiac arrhythmia or sudden death. Monitor for evidence of ventricular arrhythmias during concomitant use.

• tinidazole

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

• trifluoperazine

  trifluoperazine, pseudoephedrine. Mechanism: unknown. Use Caution/Monitor. Consider avoiding use of pseudoephedrine in patients receiving phenothiazines (especially thioridazine) due to the potential risk of cardiac arrhythmia or sudden death. Monitor for evidence of ventricular arrhythmias during concomitant use.

• warfarin

  acetaminophen increases effects of warfarin by anticoagulation. Use Caution/Monitor.

• xylometazoline

  pseudoephedrine and xylometazoline both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

Minor (14)

• acetazolamide

  acetazolamide decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

• albiglutide

  albiglutide decreases levels of acetaminophen by unspecified interaction mechanism. Minor/Significance Unknown.

• antithrombin alfa

  acetaminophen increases effects of antithrombin alfa by unknown mechanism. Minor/Significance Unknown.

• antithrombin III

  acetaminophen increases effects of antithrombin III by unknown mechanism. Minor/Significance Unknown.

• argatroban

  acetaminophen increases effects of argatroban by unknown mechanism. Minor/Significance Unknown.

• bemiparin

  acetaminophen increases effects of bemiparin by unknown mechanism. Minor/Significance Unknown.

• bivalirudin

  acetaminophen increases effects of bivalirudin by unknown mechanism. Minor/Significance Unknown.

• carbamazepine

  carbamazepine decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

• cholestyramine

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

• clonazepam

  clonazepam decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

• colestipol

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

• dalteparin

  acetaminophen increases effects of dalteparin by unknown mechanism. Minor/Significance Unknown.

• desmopressin

  desmopressin increases effects of pseudoephedrine by pharmacodynamic synergism. Minor/Significance Unknown.

• diazepam

  diazepam decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

• acetazolamide

  Monitor Closely (1)acetazolamide will increase the level or effect of pseudoephedrine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.Minor (1)acetazolamide decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

• albiglutide

  Minor (1)albiglutide decreases levels of acetaminophen by unspecified interaction mechanism. Minor/Significance Unknown.

• albuterol

  Monitor Closely (1)albuterol and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• alfuzosin

  Monitor Closely (1)pseudoephedrine decreases effects of alfuzosin by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• aluminum hydroxide

  Monitor Closely (1)aluminum hydroxide will increase the level or effect of pseudoephedrine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor. Caution advised with frequent or high dose antacids

• amitriptyline

  Serious - Use Alternative (1)amitriptyline increases effects of pseudoephedrine by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Avoid or Use Alternate Drug. Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.

• ammonium chloride

  Monitor Closely (1)ammonium chloride decreases effects of pseudoephedrine by unknown mechanism. Use Caution/Monitor. Urinary excretion of indirect acting alpha/beta agonists (eg, pseudoephedrine) may increase when administered concomitantly with urinary acidifying agents, resulting in lower serum concentrations.

• amoxapine

  Serious - Use Alternative (1)amoxapine increases effects of pseudoephedrine by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Avoid or Use Alternate Drug. Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.

• antithrombin alfa

  Minor (1)acetaminophen increases effects of antithrombin alfa by unknown mechanism. Minor/Significance Unknown.

• antithrombin III

  Minor (1)acetaminophen increases effects of antithrombin III by unknown mechanism. Minor/Significance Unknown.

• apalutamide

  Monitor Closely (1)apalutamide will decrease the level or effect of acetaminophen by increasing elimination. Use Caution/Monitor. Apalutamide induces UGT and may decrease systemic exposure of drugs that are UGT substrates.

• arformoterol

  Monitor Closely (1)arformoterol and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• argatroban

  Minor (1)acetaminophen increases effects of argatroban by unknown mechanism. Minor/Significance Unknown.

• atogepant

  Monitor Closely (1)acetaminophen will increase the level or effect of atogepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• avapritinib

  Monitor Closely (1)acetaminophen will increase the level or effect of avapritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• axitinib

  Monitor Closely (1)acetaminophen increases levels of axitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• bemiparin

  Minor (1)acetaminophen increases effects of bemiparin by unknown mechanism. Minor/Significance Unknown.

• benzphetamine

  Monitor Closely (1)benzphetamine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• bivalirudin

  Minor (1)acetaminophen increases effects of bivalirudin by unknown mechanism. Minor/Significance Unknown.

• bromocriptine

  Monitor Closely (1)bromocriptine, pseudoephedrine. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Hypertension, V tach.

• bupivacaine implant

  Monitor Closely (1)acetaminophen, bupivacaine implant. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Local anesthetics may increase the risk of developing methemoglobinemia when concurrently exposed to drugs that also cause methemoglobinemia.

• busulfan

  Monitor Closely (1)acetaminophen increases levels of busulfan by decreasing metabolism. Use Caution/Monitor. Use of acetaminophen prior to (< 72 hours) or concurrently with busulfan may result in decreased clearance of busulfan due to acetaminophen-induced decreases in glutathione levels.

• cabergoline

  Serious - Use Alternative (1)cabergoline, pseudoephedrine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension.

• carbamazepine

  Minor (1)carbamazepine decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

• chlorpromazine

  Monitor Closely (1)chlorpromazine, pseudoephedrine. Mechanism: unknown. Use Caution/Monitor. Consider avoiding use of pseudoephedrine in patients receiving phenothiazines (especially thioridazine) due to the potential risk of cardiac arrhythmia or sudden death. Monitor for evidence of ventricular arrhythmias during concomitant use.

• cholestyramine

  Minor (1)cholestyramine decreases levels of acetaminophen by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• clomipramine

  Serious - Use Alternative (1)clomipramine increases effects of pseudoephedrine by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Avoid or Use Alternate Drug. Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.

• clonazepam

  Minor (1)clonazepam decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

• cocaine topical

  Serious - Use Alternative (1)cocaine topical increases effects of pseudoephedrine by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Avoid or Use Alternate Drug.

• colestipol

  Minor (1)colestipol decreases levels of acetaminophen by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• dalteparin

  Minor (1)acetaminophen increases effects of dalteparin by unknown mechanism. Minor/Significance Unknown.

• dapsone topical

  Monitor Closely (1)acetaminophen increases toxicity of dapsone topical by altering metabolism. Modify Therapy/Monitor Closely. May induce methemoglobinemia .

• desipramine

  Serious - Use Alternative (1)desipramine increases effects of pseudoephedrine by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Avoid or Use Alternate Drug. Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.

• desmopressin

  Minor (1)desmopressin increases effects of pseudoephedrine by pharmacodynamic synergism. Minor/Significance Unknown.

• desvenlafaxine

  Serious - Use Alternative (1)desvenlafaxine increases effects of pseudoephedrine by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Avoid or Use Alternate Drug.

• dexfenfluramine

  Monitor Closely (1)dexfenfluramine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• dexmethylphenidate

  Monitor Closely (1)dexmethylphenidate and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• dextroamphetamine

  Monitor Closely (1)dextroamphetamine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• diazepam

  Minor (1)diazepam decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

• diethylpropion

  Monitor Closely (1)diethylpropion and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• dihydroergotamine

  Contraindicated (1)dihydroergotamine increases effects of pseudoephedrine by pharmacodynamic synergism. Contraindicated. Ergot derivatives may enhance the vasoconstricting effect of pseudoephedrine and eventually significantly increasing blood pressure.

• dihydroergotamine inhaled

  Contraindicated (1)dihydroergotamine inhaled increases effects of pseudoephedrine by pharmacodynamic synergism. Contraindicated. Ergot derivatives may enhance the vasoconstricting effect of pseudoephedrine and eventually significantly increasing blood pressure.

• dihydroergotamine intranasal

  Contraindicated (1)dihydroergotamine intranasal increases effects of pseudoephedrine by pharmacodynamic synergism. Contraindicated. Ergot derivatives may enhance the vasoconstricting effect of pseudoephedrine and eventually significantly increasing blood pressure.

• disulfiram

  Minor (1)disulfiram will increase the level or effect of acetaminophen by affecting hepatic enzyme CYP2E1 metabolism. Minor/Significance Unknown.

• dobutamine

  Monitor Closely (1)dobutamine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• dopamine

  Monitor Closely (1)dopamine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• dopexamine

  Monitor Closely (1)dopexamine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• doxapram

  Serious - Use Alternative (1)doxapram increases effects of pseudoephedrine by pharmacodynamic synergism. Avoid or Use Alternate Drug. Additive pressor effect.

• doxazosin

  Monitor Closely (1)pseudoephedrine decreases effects of doxazosin by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• doxepin

  Serious - Use Alternative (1)doxepin increases effects of pseudoephedrine by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Avoid or Use Alternate Drug. Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.

• droxidopa

  Monitor Closely (1)pseudoephedrine and droxidopa both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. May increase risk for supine hypertension

• duloxetine

  Serious - Use Alternative (1)duloxetine increases effects of pseudoephedrine by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Avoid or Use Alternate Drug.

• eltrombopag

  Monitor Closely (1)eltrombopag increases levels of acetaminophen by decreasing metabolism. Use Caution/Monitor. UGT inhibition; significance of interaction unclear.

• enoxaparin

  Minor (1)acetaminophen increases effects of enoxaparin by unknown mechanism. Minor/Significance Unknown.

• ephedrine

  Monitor Closely (2)ephedrine, pseudoephedrine. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor.
  
  ephedrine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• epinephrine

  Monitor Closely (1)epinephrine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• epinephrine inhaled

  Monitor Closely (1)pseudoephedrine, epinephrine inhaled. Either increases effects of the other by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• epinephrine racemic

  Monitor Closely (1)epinephrine racemic and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• ergoloid mesylates

  Contraindicated (1)ergoloid mesylates increases effects of pseudoephedrine by pharmacodynamic synergism. Contraindicated. Ergot derivatives may enhance the vasoconstricting effect of pseudoephedrine and eventually significantly increasing blood pressure.

• ergonovine

  Contraindicated (1)ergonovine increases effects of pseudoephedrine by pharmacodynamic synergism. Contraindicated. Ergot derivatives may enhance the vasoconstricting effect of pseudoephedrine and eventually significantly increasing blood pressure.

• ergotamine

  Contraindicated (1)ergotamine increases effects of pseudoephedrine by pharmacodynamic synergism. Contraindicated. Ergot derivatives may enhance the vasoconstricting effect of pseudoephedrine and eventually significantly increasing blood pressure.

• esketamine intranasal

  Monitor Closely (1)esketamine intranasal, pseudoephedrine. 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. .

• ethanol

  Minor (2)ethanol will decrease the level or effect of acetaminophen by affecting hepatic enzyme CYP2E1 metabolism. Minor/Significance Unknown.
  
  ethanol increases toxicity of acetaminophen by decreasing metabolism. Minor/Significance Unknown.

• ethosuximide

  Minor (1)ethosuximide decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

• exenatide injectable solution

  Monitor Closely (1)exenatide injectable solution will decrease the level or effect of acetaminophen by unspecified interaction mechanism. Use Caution/Monitor. To avoid potential interaction, give acetaminophen at least 1 hour before or 4 hours after exenatide injection.

• exenatide injectable suspension

  Monitor Closely (1)exenatide injectable suspension will decrease the level or effect of acetaminophen by unspecified interaction mechanism. Use Caution/Monitor. To avoid potential interaction, give acetaminophen at least 1 hour before or 4 hours after exenatide injection.

• felbamate

  Minor (1)felbamate decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

• fenfluramine

  Monitor Closely (1)fenfluramine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• finerenone

  Monitor Closely (1)acetaminophen 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 moderate CYP3A4 inhibitors. Adjust finererone dosage as needed.

• flibanserin

  Monitor Closely (1)acetaminophen 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.

• fluphenazine

  Monitor Closely (1)fluphenazine, pseudoephedrine. Mechanism: unknown. Use Caution/Monitor. Consider avoiding use of pseudoephedrine in patients receiving phenothiazines (especially thioridazine) due to the potential risk of cardiac arrhythmia or sudden death. Monitor for evidence of ventricular arrhythmias during concomitant use.

• fondaparinux

  Minor (1)acetaminophen increases effects of fondaparinux by unknown mechanism. Minor/Significance Unknown.

• formoterol

  Monitor Closely (1)formoterol and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• fosphenytoin

  Minor (1)fosphenytoin decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

• green tea

  Minor (1)green tea increases effects of acetaminophen by pharmacodynamic synergism. Minor/Significance Unknown. (Theoretical, due to caffeine content).

• heparin

  Minor (1)acetaminophen increases effects of heparin by unknown mechanism. Minor/Significance Unknown.

• hydralazine

  Monitor Closely (1)hydralazine, pseudoephedrine. Mechanism: pharmacodynamic antagonism. Use Caution/Monitor. Sympathomimetics can antagonize the activity of some antihypertensive agents.

• imatinib

  Monitor Closely (1)imatinib decreases levels of acetaminophen by decreasing hepatic clearance. Modify Therapy/Monitor Closely. In vitro, imatinib was found to inhibit acetaminophen O-glucuronidation (Ki value of 58.5 micro-M) at therapeutic levels; avoid chronic acetaminophen therapy with imatinib; if occasional acetaminophen administered, do not exceed 1300 mg/day.

• imipramine

  Serious - Use Alternative (1)imipramine increases effects of pseudoephedrine by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Avoid or Use Alternate Drug. Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.

• insulin degludec

  Monitor Closely (1)pseudoephedrine decreases effects of insulin degludec by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. Sympathomimetics increase blood glucose by stimulating alpha and beta receptors; this action results in increased hepatic glucose production, glycogenolysis, and decreased insulin secretion.

• insulin degludec/insulin aspart

  Monitor Closely (1)pseudoephedrine decreases effects of insulin degludec/insulin aspart by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. Sympathomimetics increase blood glucose by stimulating alpha and beta receptors; this action results in increased hepatic glucose production, glycogenolysis, and decreased insulin secretion.

• insulin detemir

  Monitor Closely (1)pseudoephedrine decreases effects of insulin detemir by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. Sympathomimetics increase blood glucose by stimulating alpha and beta receptors; this action results in increased hepatic glucose production, glycogenolysis, and decreased insulin secretion.

• insulin glargine

  Monitor Closely (1)pseudoephedrine decreases effects of insulin glargine by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. Sympathomimetics increase blood glucose by stimulating alpha and beta receptors; this action results in increased hepatic glucose production, glycogenolysis, and decreased insulin secretion.

• insulin inhaled

  Monitor Closely (1)pseudoephedrine decreases effects of insulin inhaled by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. Sympathomimetics increase blood glucose by stimulating alpha and beta receptors; this action results in increased hepatic glucose production, glycogenolysis, and decreased insulin secretion.

• insulin regular human

  Monitor Closely (1)pseudoephedrine decreases effects of insulin regular human by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. Sympathomimetics increase blood glucose by stimulating alpha and beta receptors; this action results in increased hepatic glucose production, glycogenolysis, and decreased insulin secretion.

• iobenguane I 123

  Serious - Use Alternative (1)pseudoephedrine decreases effects of iobenguane I 123 by receptor binding competition. Avoid or Use Alternate Drug. If clinically appropriate, discontinue drugs that compete for NE receptor sites for at least 5 half-lives; may cause false-negative imaging results. Do not administer pseudoephedrine until at least 7 days after each iobenguane dose.

• iobenguane I 131

  Serious - Use Alternative (1)pseudoephedrine decreases effects of iobenguane I 131 by receptor binding competition. Avoid or Use Alternate Drug. If clinically appropriate, discontinue drugs that compete for NE receptor sites for at least 5 half-lives; may cause false-negative imaging results. Do not administer pseudoephedrine until at least 7 days after each iobenguane dose.

• isavuconazonium sulfate

  Monitor Closely (1)acetaminophen will increase the level or effect of isavuconazonium sulfate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• isocarboxazid

  Contraindicated (1)isocarboxazid increases effects of pseudoephedrine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.

• isoflurane

  Serious - Use Alternative (1)isoflurane increases toxicity of pseudoephedrine by Mechanism: unknown. Avoid or Use Alternate Drug. Risk of V tach, HTN.

• isoniazid

  Monitor Closely (1)isoniazid will increase the level or effect of acetaminophen by affecting hepatic enzyme CYP2E1 metabolism. Use Caution/Monitor.Minor (1)isoniazid increases toxicity of acetaminophen by unknown mechanism. Minor/Significance Unknown.

• isoproterenol

  Monitor Closely (1)isoproterenol and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• ivacaftor

  Monitor Closely (1)acetaminophen increases levels of ivacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor when coadministered with weak CYP3A4 inhibitors .

• lacosamide

  Minor (1)lacosamide decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

• lamotrigine

  Minor (1)lamotrigine decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

• lemborexant

  Monitor Closely (1)acetaminophen 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

  Monitor Closely (1)levalbuterol and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• levetiracetam

  Minor (1)levetiracetam decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

• levomilnacipran

  Serious - Use Alternative (1)levomilnacipran increases effects of pseudoephedrine by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Avoid or Use Alternate Drug.

• levonorgestrel oral/ethinylestradiol/ferrous bisglycinate

  Monitor Closely (2)levonorgestrel oral/ethinylestradiol/ferrous bisglycinate will decrease the level or effect of acetaminophen by unknown mechanism. Use Caution/Monitor.
  
  acetaminophen increases levels of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by decreasing hepatic clearance. Use Caution/Monitor. Coadministration of ascorbic acid and certain combined hormonal contraceptives (CHCs) containing EE may increase plasma EE concentrations, possibly by inhibition of conjugation.

• linezolid

  Contraindicated (1)linezolid increases effects of pseudoephedrine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.

• liraglutide

  Minor (1)liraglutide decreases levels of acetaminophen by unspecified interaction mechanism. Minor/Significance Unknown.

• lisdexamfetamine

  Monitor Closely (1)lisdexamfetamine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• lixisenatide (DSC)

  Monitor Closely (1)lixisenatide (DSC) will decrease the level or effect of acetaminophen by inhibition of GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. GLP1 agonists delay gastric emptying, which may affect absorption of concomitantly administered oral medications. No effects on acetaminophen Cmax and Tmax were observed when acetaminophen was administered 1 hr before lixisenatide. When administered 1 or 4 hr after lixisenatide, acetaminophen Cmax was decreased by 29% and 31% respectively and median Tmax was delayed by 2 and 1.75 hr, respectively.

• lofepramine

  Serious - Use Alternative (1)lofepramine, pseudoephedrine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.

• lomitapide

  Monitor Closely (1)acetaminophen increases levels of lomitapide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Lomitapide dose should not exceed 30 mg/day.

• lonafarnib

  Serious - Use Alternative (1)acetaminophen 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.

• lorazepam

  Minor (1)lorazepam decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

• maprotiline

  Serious - Use Alternative (1)maprotiline, pseudoephedrine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.

• metaproterenol

  Monitor Closely (1)metaproterenol and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• methamphetamine

  Monitor Closely (1)methamphetamine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• methenamine

  Monitor Closely (1)methenamine decreases effects of pseudoephedrine by unknown mechanism. Use Caution/Monitor. Urinary excretion of indirect acting alpha/beta agonists (eg, pseudoephedrine) may increase when administered concomitantly with urinary acidifying agents, resulting in lower serum concentrations.

• methoxyflurane

  Serious - Use Alternative (1)methoxyflurane increases toxicity of pseudoephedrine by Mechanism: unknown. Avoid or Use Alternate Drug. Risk of V tach, HTN.

• methsuximide

  Minor (1)methsuximide decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

• methyldopa

  Monitor Closely (1)methyldopa increases effects of pseudoephedrine by unknown mechanism. Use Caution/Monitor.

• methylenedioxymethamphetamine

  Monitor Closely (1)methylenedioxymethamphetamine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• methylergonovine

  Contraindicated (1)methylergonovine increases effects of pseudoephedrine by pharmacodynamic synergism. Contraindicated. Ergot derivatives may enhance the vasoconstricting effect of pseudoephedrine and eventually significantly increasing blood pressure.

• metoclopramide

  Minor (1)metoclopramide increases levels of acetaminophen by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• metronidazole

  Minor (1)metronidazole will increase the level or effect of acetaminophen by affecting hepatic enzyme CYP2E1 metabolism. Minor/Significance Unknown.

• midazolam intranasal

  Monitor Closely (1)acetaminophen 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.

• midodrine

  Monitor Closely (1)midodrine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• milnacipran

  Serious - Use Alternative (1)milnacipran increases effects of pseudoephedrine by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Avoid or Use Alternate Drug.

• mipomersen

  Monitor Closely (1)mipomersen, acetaminophen. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Both drugs have potential to increase hepatic enzymes; monitor LFTs.

• nateglinide

  Monitor Closely (1)pseudoephedrine decreases effects of nateglinide by pharmacodynamic antagonism. Use Caution/Monitor. Coadministration may reduce nateglinide's hypoglycemic action.

• norepinephrine

  Monitor Closely (1)norepinephrine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• nortriptyline

  Serious - Use Alternative (1)nortriptyline increases effects of pseudoephedrine by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Avoid or Use Alternate Drug. Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.

• olodaterol inhaled

  Monitor Closely (1)pseudoephedrine and olodaterol inhaled both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. Caution with coadministration of adrenergic drugs by any route because of additive sympathetic effects

• oxcarbazepine

  Minor (1)oxcarbazepine decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

• oxybutynin

  Minor (1)oxybutynin decreases levels of acetaminophen by unspecified interaction mechanism. Minor/Significance Unknown.

• oxybutynin topical

  Minor (1)oxybutynin topical decreases levels of acetaminophen by unspecified interaction mechanism. Minor/Significance Unknown.

• oxybutynin transdermal

  Minor (1)oxybutynin transdermal decreases levels of acetaminophen by unspecified interaction mechanism. Minor/Significance Unknown.

• oxytocin

  Monitor Closely (1)oxytocin increases effects of pseudoephedrine by pharmacodynamic synergism. Use Caution/Monitor.

• ozanimod

  Serious - Use Alternative (1)ozanimod increases toxicity of pseudoephedrine 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.

• perphenazine

  Monitor Closely (1)perphenazine, pseudoephedrine. Mechanism: unknown. Use Caution/Monitor. Consider avoiding use of pseudoephedrine in patients receiving phenothiazines (especially thioridazine) due to the potential risk of cardiac arrhythmia or sudden death. Monitor for evidence of ventricular arrhythmias during concomitant use.

• pexidartinib

  Serious - Use Alternative (1)acetaminophen and pexidartinib both increase Other (see comment). Avoid or Use Alternate Drug. Pexidartinib can cause hepatotoxicity. Avoid coadministration of pexidartinib with other products know to cause hepatoxicity.

• phendimetrazine

  Monitor Closely (1)phendimetrazine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• phenelzine

  Contraindicated (1)phenelzine increases effects of pseudoephedrine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.

• phenindione

  Minor (1)acetaminophen increases effects of phenindione by unknown mechanism. Minor/Significance Unknown.

• phenobarbital

  Minor (1)phenobarbital decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

• phentermine

  Monitor Closely (1)phentermine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• phenylephrine

  Monitor Closely (1)phenylephrine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• phenylephrine PO

  Monitor Closely (1)phenylephrine PO and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• phenytoin

  Minor (1)phenytoin decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

• pirbuterol

  Monitor Closely (1)pirbuterol and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• potassium phosphate

  Monitor Closely (1)potassium phosphate decreases effects of pseudoephedrine by unknown mechanism. Use Caution/Monitor. Urinary excretion of indirect acting alpha/beta agonists (eg, pseudoephedrine) may increase when administered concomitantly with urinary acidifying agents, resulting in lower serum concentrations.

• pretomanid

  Serious - Use Alternative (1)acetaminophen, pretomanid. Either increases toxicity of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Pretomanid regimen associated with hepatotoxicity. Avoid alcohol and hepatotoxic agents, including herbal supplements and drugs other than bedaquiline and linezolid.

• primidone

  Minor (1)primidone decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

• procarbazine

  Contraindicated (1)procarbazine increases effects of pseudoephedrine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.

• prochlorperazine

  Monitor Closely (1)prochlorperazine, pseudoephedrine. Mechanism: unknown. Use Caution/Monitor. Consider avoiding use of pseudoephedrine in patients receiving phenothiazines (especially thioridazine) due to the potential risk of cardiac arrhythmia or sudden death. Monitor for evidence of ventricular arrhythmias during concomitant use.

• promazine

  Monitor Closely (1)promazine, pseudoephedrine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.

• promethazine

  Monitor Closely (1)promethazine, pseudoephedrine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.

• propylhexedrine

  Monitor Closely (1)propylhexedrine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• protamine

  Minor (1)acetaminophen increases effects of protamine by unknown mechanism. Minor/Significance Unknown.

• protriptyline

  Serious - Use Alternative (1)protriptyline increases effects of pseudoephedrine by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Avoid or Use Alternate Drug. Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.

• rasagiline

  Contraindicated (1)rasagiline increases effects of pseudoephedrine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.

• rifabutin

  Minor (1)rifabutin decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

• rifampin

  Minor (1)rifampin decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

• rufinamide

  Minor (1)rufinamide decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

• ruxolitinib

  Minor (1)acetaminophen will increase the level or effect of ruxolitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• ruxolitinib topical

  Minor (1)acetaminophen will increase the level or effect of ruxolitinib topical by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• safinamide

  Monitor Closely (1)pseudoephedrine and safinamide both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. Monitor patients for hypertension if safinamide is prescribed concomitantly with prescription or nonprescription sympathomimetics, including nasal, oral, or ophthalmic decongestants and cold remedies.

• salmeterol

  Monitor Closely (1)salmeterol and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• selegiline

  Contraindicated (1)selegiline increases effects of pseudoephedrine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.

• selegiline transdermal

  Contraindicated (1)selegiline transdermal increases effects of pseudoephedrine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.

• serdexmethylphenidate/dexmethylphenidate

  Monitor Closely (2)serdexmethylphenidate/dexmethylphenidate and pseudoephedrine both decrease sedation. Use Caution/Monitor.
  
  serdexmethylphenidate/dexmethylphenidate and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• sevoflurane

  Serious - Use Alternative (1)sevoflurane increases toxicity of pseudoephedrine by Mechanism: unknown. Avoid or Use Alternate Drug. Risk of V tach, HTN.

• silodosin

  Monitor Closely (1)pseudoephedrine decreases effects of silodosin by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• sodium bicarbonate

  Monitor Closely (1)sodium bicarbonate will increase the level or effect of pseudoephedrine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor. Caution advised with frequent or high dose antacids

• sodium citrate/citric acid

  Monitor Closely (1)sodium citrate/citric acid will increase the level or effect of pseudoephedrine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

• sodium lactate

  Monitor Closely (1)sodium lactate will increase the level or effect of pseudoephedrine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

• sodium phosphates, IV

  Monitor Closely (1)sodium phosphates, IV decreases effects of pseudoephedrine by unknown mechanism. Use Caution/Monitor. Urinary excretion of indirect acting alpha/beta agonists (eg, pseudoephedrine) may increase when administered concomitantly with urinary acidifying agents, resulting in lower serum concentrations.

• solriamfetol

  Monitor Closely (1)pseudoephedrine and solriamfetol both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• spironolactone

  Monitor Closely (1)spironolactone decreases effects of pseudoephedrine by pharmacodynamic antagonism. Use Caution/Monitor.

• tamsulosin

  Monitor Closely (1)pseudoephedrine decreases effects of tamsulosin by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• tazemetostat

  Monitor Closely (1)acetaminophen will increase the level or effect of tazemetostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• terazosin

  Monitor Closely (1)pseudoephedrine decreases effects of terazosin by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• terbutaline

  Monitor Closely (1)terbutaline and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• tetracaine

  Monitor Closely (1)tetracaine, acetaminophen. Other (see comment). Use Caution/Monitor. Comment: Monitor for signs of methemoglobinemia when methemoglobin-inducing drugs are coadministered.

• thioridazine

  Monitor Closely (1)thioridazine, pseudoephedrine. Mechanism: unknown. Use Caution/Monitor. Consider avoiding use of pseudoephedrine in patients receiving phenothiazines (especially thioridazine) due to the potential risk of cardiac arrhythmia or sudden death. Monitor for evidence of ventricular arrhythmias during concomitant use.

• tiagabine

  Minor (1)tiagabine decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

• tinidazole

  Monitor Closely (1)acetaminophen will increase the level or effect of tinidazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• topiramate

  Minor (1)topiramate decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

• tranylcypromine

  Contraindicated (1)tranylcypromine increases effects of pseudoephedrine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.

• trazodone

  Serious - Use Alternative (1)trazodone, pseudoephedrine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.

• trifluoperazine

  Monitor Closely (1)trifluoperazine, pseudoephedrine. Mechanism: unknown. Use Caution/Monitor. Consider avoiding use of pseudoephedrine in patients receiving phenothiazines (especially thioridazine) due to the potential risk of cardiac arrhythmia or sudden death. Monitor for evidence of ventricular arrhythmias during concomitant use.

• trimipramine

  Serious - Use Alternative (1)trimipramine increases effects of pseudoephedrine by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Avoid or Use Alternate Drug. Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.

• valproic acid

  Minor (1)valproic acid decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

• venlafaxine

  Serious - Use Alternative (1)venlafaxine increases effects of pseudoephedrine by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Avoid or Use Alternate Drug.

• warfarin

  Monitor Closely (1)acetaminophen increases effects of warfarin by anticoagulation. Use Caution/Monitor.

• xylometazoline

  Monitor Closely (1)pseudoephedrine and xylometazoline both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

• zonisamide

  Minor (1)zonisamide decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism increase levels of hepatotoxic metabolites.