cetirizine/pseudoephedrine (OTC)

Allergic Rhinitis

Indicated to relieve nasal and non-nasal symptoms associated with seasonal or perennial allergic rhinitis

1 tablet PO q12hr with or without food; not to exceed 2 tabs/day

Renal Impairment

Use caution; dose adjustment to 1 tablet per day may be necessary

Hemodialysis or CrCl <32 mL/min: 1 tablet PO qDay

Hepatic Impairment

Use caution; dose adjustment to 1 tablet per day may be necessary

Allergic Rhinitis

Indicated to relieve nasal and non-nasal symptoms associated with seasonal or perennial allergic rhinitis

<12 years: Safety and efficacy not established

≥12 years: As adults; 1 tablet PO q12hr with or without food; not to exceed 2 tabs/day

Renal Impairment

Use caution; dose adjustment to 1 tablet per day may be necessary

Hemodialysis or CrCl <32 mL/min: 1 tablet PO qDay

Hepatic Impairment

Use caution; dose adjustment to 1 tablet per day may be necessary

>65 years: Use caution; may require decreased dose of 1 tablet PO qDay depending on renal function

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 (32)

• 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.

• erdafitinib

  erdafitinib will increase the level or effect of cetirizine by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. If coadministration unavoidable, separate administration by at least 6 hr before or after administration of P-gp substrates with narrow therapeutic index.

• 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.

• isocarboxazid

  isocarboxazid increases effects of cetirizine by Other (see comment). Avoid or Use Alternate Drug. Comment: Isocarboxazid should not be administered in combination with antihistamines because of potential additive CNS depressant effects. MAO inhibitors also prolong and intensify anticholinergic effects of antihistamines. .

• isoflurane

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

• lasmiditan

  lasmiditan increases levels of cetirizine by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.

• 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.

• 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.

• metoclopramide intranasal

  cetirizine, 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.

• 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.

• olopatadine intranasal

  cetirizine 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 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.

• 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.

• sevoflurane

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

• sotorasib

  sotorasib will decrease the level or effect of cetirizine by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. If use is unavoidable, refer to the prescribing information of the P-gp substrate for dosage modifications.

• tepotinib

  tepotinib will increase the level or effect of cetirizine by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. If concomitant use unavoidable, reduce the P-gp substrate dosage if recommended in its approved product labeling.

• tranylcypromine

  tranylcypromine increases effects of cetirizine by Other (see comment). Avoid or Use Alternate Drug. Comment: Tranylcypromine should not be administered in combination with antihistamines because of potential additive CNS depressant effects. MAO inhibitors also prolong and intensify anticholinergic effects of antihistamines.

• trazodone

  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.

Monitor Closely (118)

• acetazolamide

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

• acrivastine

  acrivastine and cetirizine both increase sedation. 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

• amifampridine

  cetirizine increases toxicity of amifampridine by Other (see comment). Modify Therapy/Monitor Closely. Comment: Amifampridine can cause seizures. Coadministration with drugs that lower seizure threshold may increase this risk.

• amisulpride

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

• 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.

• arformoterol

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

• asenapine

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

• asenapine transdermal

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

• avapritinib

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

• azithromycin

  azithromycin will increase the level or effect of cetirizine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• benzhydrocodone/acetaminophen

  benzhydrocodone/acetaminophen and cetirizine both increase sedation. Use Caution/Monitor.

• benzphetamine

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

• berotralstat

  berotralstat will increase the level or effect of cetirizine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Monitor or titrate P-gp substrate dose if coadministered.

• bosutinib

  bosutinib increases levels of cetirizine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• brexpiprazole

  brexpiprazole and cetirizine both increase sedation. Use Caution/Monitor.

• brimonidine

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

• brivaracetam

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

• bromocriptine

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

• buprenorphine subdermal implant

  buprenorphine subdermal implant and cetirizine both increase sedation. Use Caution/Monitor.

• buprenorphine transdermal

  buprenorphine transdermal and cetirizine both increase sedation. Use Caution/Monitor.

• buprenorphine, long-acting injection

  buprenorphine, long-acting injection and cetirizine both increase sedation. Use Caution/Monitor.

• cenobamate

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

• 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.

• clobazam

  cetirizine, clobazam. Other (see comment). Use Caution/Monitor. Comment: Concomitant administration can increase the potential for CNS effects (e.g., increased sedation or respiratory depression).

• crizotinib

  crizotinib increases levels of cetirizine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• daridorexant

  cetirizine 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.

• 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.

• diazepam intranasal

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

• 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.

• donepezil transdermal

  donepezil transdermal, cetirizine. Either decreases effects of the other by pharmacodynamic antagonism. 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

• elagolix

  elagolix will increase the level or effect of cetirizine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• eliglustat

  eliglustat increases levels of cetirizine by P-glycoprotein (MDR1) efflux transporter. Modify Therapy/Monitor Closely. Monitor therapeutic drug concentrations, as indicated, or consider reducing the dosage of the P-gp substrate and titrate to clinical effect.

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

• fenfluramine

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

• fentanyl

  fentanyl and cetirizine both increase sedation. Use Caution/Monitor.

• fentanyl intranasal

  fentanyl intranasal and cetirizine both increase sedation. Use Caution/Monitor.

• fentanyl iontophoretic transdermal system

  fentanyl iontophoretic transdermal system and cetirizine both increase sedation. Use Caution/Monitor.

• fentanyl transdermal

  fentanyl transdermal and cetirizine both increase sedation. Use Caution/Monitor.

• 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.

• fostamatinib

  fostamatinib will increase the level or effect of cetirizine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Concomitant use of fostamatinib may increase concentrations of P-gp substrates. Monitor for toxicities of the P-gp substrate drug that may require dosage reduction when given concurrently with fostamatinib.

• gabapentin

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

• gabapentin enacarbil

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

• glecaprevir/pibrentasvir

  glecaprevir/pibrentasvir will increase the level or effect of cetirizine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• hyaluronidase

  cetirizine decreases effects of hyaluronidase by Other (see comment). Use Caution/Monitor. Comment: Antihistamines, 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

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

• 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.

• isoproterenol

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

• istradefylline

  istradefylline will increase the level or effect of cetirizine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Istradefylline 40 mg/day increased peak levels and AUC of P-gp substrates in clinical trials. Consider dose reduction of sensitive P-gp substrates.

• levalbuterol

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

• lisdexamfetamine

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

• lomitapide

  lomitapide increases levels of cetirizine by P-glycoprotein (MDR1) efflux transporter. Modify Therapy/Monitor Closely. Consider reducing dose when used concomitantly with lomitapide.

• lurasidone

  lurasidone, cetirizine. 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.

• 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

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

• midodrine

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

• 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.

• phenelzine

  phenelzine increases effects of cetirizine by Other (see comment). Modify Therapy/Monitor Closely. Comment: Coadministration of phenelzine and antihistamines may result in additive CNS depressant effects. MAO inhibitors also prolong and intensify anticholinergic effects of antihistamines. .

• 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.

• ponatinib

  ponatinib increases levels of cetirizine by P-glycoprotein (MDR1) efflux transporter. 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.

• pregabalin

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

• 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.

• ritonavir

  ritonavir increases levels of cetirizine by decreasing metabolism. 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.

• sarecycline

  sarecycline will increase the level or effect of cetirizine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Monitor for toxicities of P-gp substrates that may require dosage reduction when coadministered with P-gp inhibitors.

• 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.

• stiripentol

  stiripentol will increase the level or effect of cetirizine by P-glycoprotein (MDR1) efflux transporter. Modify Therapy/Monitor Closely. Consider reducing the dose of P-glycoprotein (P-gp) substrates, if adverse reactions are experienced when administered concomitantly with stiripentol.
  
  stiripentol, cetirizine. Either increases effects of the other by sedation. Use Caution/Monitor. Concurrent use of medications with CNS depressant effects together with thalidomide should be avoided due to the risk for additive sedative effects.

• tamsulosin

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

• 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.

• 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.

• tucatinib

  tucatinib will increase the level or effect of cetirizine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Consider reducing the dosage of P-gp substrates, where minimal concentration changes may lead to serious or life-threatening toxicities.

• vemurafenib

  vemurafenib increases levels of cetirizine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• xylometazoline

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

Minor (2)

• desmopressin

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

• theophylline

  theophylline increases levels of cetirizine by decreasing elimination. Minor/Significance Unknown.

• acetazolamide

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

• acrivastine

  Monitor Closely (1)acrivastine and cetirizine both increase sedation. Use Caution/Monitor.

• 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

• amifampridine

  Monitor Closely (1)cetirizine increases toxicity of amifampridine by Other (see comment). Modify Therapy/Monitor Closely. Comment: Amifampridine can cause seizures. Coadministration with drugs that lower seizure threshold may increase this risk.

• amisulpride

  Monitor Closely (1)amisulpride and cetirizine both increase sedation. Use Caution/Monitor.

• 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.

• arformoterol

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

• asenapine

  Monitor Closely (1)asenapine and cetirizine both increase sedation. Use Caution/Monitor.

• asenapine transdermal

  Monitor Closely (1)asenapine transdermal and cetirizine both increase sedation. Use Caution/Monitor.

• avapritinib

  Monitor Closely (1)avapritinib and cetirizine both increase sedation. Use Caution/Monitor.

• azithromycin

  Monitor Closely (1)azithromycin will increase the level or effect of cetirizine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• benzhydrocodone/acetaminophen

  Monitor Closely (1)benzhydrocodone/acetaminophen and cetirizine both increase sedation. Use Caution/Monitor.

• benzphetamine

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

• berotralstat

  Monitor Closely (1)berotralstat will increase the level or effect of cetirizine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Monitor or titrate P-gp substrate dose if coadministered.

• bosutinib

  Monitor Closely (1)bosutinib increases levels of cetirizine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• brexpiprazole

  Monitor Closely (1)brexpiprazole and cetirizine both increase sedation. Use Caution/Monitor.

• brimonidine

  Monitor Closely (1)brimonidine and cetirizine both increase sedation. Use Caution/Monitor.

• brivaracetam

  Monitor Closely (1)brivaracetam and cetirizine both increase sedation. Use Caution/Monitor.

• bromocriptine

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

• buprenorphine subdermal implant

  Monitor Closely (1)buprenorphine subdermal implant and cetirizine both increase sedation. Use Caution/Monitor.

• buprenorphine transdermal

  Monitor Closely (1)buprenorphine transdermal and cetirizine both increase sedation. Use Caution/Monitor.

• buprenorphine, long-acting injection

  Monitor Closely (1)buprenorphine, long-acting injection and cetirizine both increase sedation. Use Caution/Monitor.

• cabergoline

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

• cenobamate

  Monitor Closely (1)cenobamate, cetirizine. Either increases effects of the other by sedation. Use Caution/Monitor.

• 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.

• clobazam

  Monitor Closely (1)cetirizine, clobazam. Other (see comment). Use Caution/Monitor. Comment: Concomitant administration can increase the potential for CNS effects (e.g., increased sedation or respiratory depression).

• 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.

• 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.

• crizotinib

  Monitor Closely (1)crizotinib increases levels of cetirizine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• daridorexant

  Monitor Closely (1)cetirizine 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.

• 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 intranasal

  Monitor Closely (1)diazepam intranasal, cetirizine. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration may potentiate the CNS-depressant effects of each drug.

• 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.

• dobutamine

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

• donepezil transdermal

  Monitor Closely (1)donepezil transdermal, cetirizine. Either decreases effects of the other by pharmacodynamic antagonism. 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.

• elagolix

  Monitor Closely (1)elagolix will increase the level or effect of cetirizine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• eliglustat

  Monitor Closely (1)eliglustat increases levels of cetirizine by P-glycoprotein (MDR1) efflux transporter. Modify Therapy/Monitor Closely. Monitor therapeutic drug concentrations, as indicated, or consider reducing the dosage of the P-gp substrate and titrate to clinical effect.

• 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.

• erdafitinib

  Serious - Use Alternative (1)erdafitinib will increase the level or effect of cetirizine by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. If coadministration unavoidable, separate administration by at least 6 hr before or after administration of P-gp substrates with narrow therapeutic index.

• 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 (2)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. .
  
  esketamine intranasal, cetirizine. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely.

• fenfluramine

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

• fentanyl

  Monitor Closely (1)fentanyl and cetirizine both increase sedation. Use Caution/Monitor.

• fentanyl intranasal

  Monitor Closely (1)fentanyl intranasal and cetirizine both increase sedation. Use Caution/Monitor.

• fentanyl iontophoretic transdermal system

  Monitor Closely (1)fentanyl iontophoretic transdermal system and cetirizine both increase sedation. Use Caution/Monitor.

• fentanyl transdermal

  Monitor Closely (1)fentanyl transdermal and cetirizine both increase sedation. Use Caution/Monitor.

• 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.

• formoterol

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

• fostamatinib

  Monitor Closely (1)fostamatinib will increase the level or effect of cetirizine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Concomitant use of fostamatinib may increase concentrations of P-gp substrates. Monitor for toxicities of the P-gp substrate drug that may require dosage reduction when given concurrently with fostamatinib.

• gabapentin

  Monitor Closely (1)gabapentin, cetirizine. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of CNS depressants can result in serious, life-threatening, and fatal respiratory depression. Use lowest dose possible and monitor for respiratory depression and sedation.

• gabapentin enacarbil

  Monitor Closely (1)gabapentin enacarbil, cetirizine. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of CNS depressants can result in serious, life-threatening, and fatal respiratory depression. Use lowest dose possible and monitor for respiratory depression and sedation.

• glecaprevir/pibrentasvir

  Monitor Closely (1)glecaprevir/pibrentasvir will increase the level or effect of cetirizine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• hyaluronidase

  Monitor Closely (1)cetirizine decreases effects of hyaluronidase by Other (see comment). Use Caution/Monitor. Comment: Antihistamines, when given in large systemic doses, may render tissues partially resistant to the action of hyaluronidase. Patients may require larger amounts of hyaluronidase for equivalent dispersing effect. .

• hydralazine

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

• 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.

• isocarboxazid

  Contraindicated (1)isocarboxazid increases effects of pseudoephedrine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.Serious - Use Alternative (1)isocarboxazid increases effects of cetirizine by Other (see comment). Avoid or Use Alternate Drug. Comment: Isocarboxazid should not be administered in combination with antihistamines because of potential additive CNS depressant effects. MAO inhibitors also prolong and intensify anticholinergic effects of antihistamines. .

• isoflurane

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

• isoproterenol

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

• istradefylline

  Monitor Closely (1)istradefylline will increase the level or effect of cetirizine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Istradefylline 40 mg/day increased peak levels and AUC of P-gp substrates in clinical trials. Consider dose reduction of sensitive P-gp substrates.

• lasmiditan

  Serious - Use Alternative (1)lasmiditan increases levels of cetirizine by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.

• levalbuterol

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

• 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.

• linezolid

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

• lisdexamfetamine

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

• 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)lomitapide increases levels of cetirizine by P-glycoprotein (MDR1) efflux transporter. Modify Therapy/Monitor Closely. Consider reducing dose when used concomitantly with lomitapide.

• lurasidone

  Monitor Closely (1)lurasidone, cetirizine. 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

  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.

• 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 intranasal

  Serious - Use Alternative (1)cetirizine, 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.

• midazolam intranasal

  Monitor Closely (1)midazolam intranasal, cetirizine. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Concomitant use of barbiturates, alcohol, or other CNS depressants may increase the risk of hypoventilation, airway obstruction, desaturation, or apnea and may contribute to profound and/or prolonged drug effect.

• midodrine

  Monitor Closely (1)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.

• 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

• olopatadine intranasal

  Serious - Use Alternative (1)cetirizine 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.

• 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.

• 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.Monitor Closely (1)phenelzine increases effects of cetirizine by Other (see comment). Modify Therapy/Monitor Closely. Comment: Coadministration of phenelzine and antihistamines may result in additive CNS depressant effects. MAO inhibitors also prolong and intensify anticholinergic effects of antihistamines. .

• 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.

• pirbuterol

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

• ponatinib

  Monitor Closely (1)ponatinib increases levels of cetirizine by P-glycoprotein (MDR1) efflux transporter. 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.

• pregabalin

  Monitor Closely (1)pregabalin, cetirizine. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of CNS depressants can result in serious, life-threatening, and fatal respiratory depression. Use lowest dose possible and monitor for respiratory depression and sedation.

• 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.

• 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.

• ritonavir

  Monitor Closely (1)ritonavir increases levels of cetirizine by decreasing metabolism. Use Caution/Monitor.

• 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.

• sarecycline

  Monitor Closely (1)sarecycline will increase the level or effect of cetirizine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Monitor for toxicities of P-gp substrates that may require dosage reduction when coadministered with P-gp inhibitors.

• 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.

• sotorasib

  Serious - Use Alternative (1)sotorasib will decrease the level or effect of cetirizine by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. If use is unavoidable, refer to the prescribing information of the P-gp substrate for dosage modifications.

• spironolactone

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

• stiripentol

  Monitor Closely (2)stiripentol, cetirizine. Either increases effects of the other by sedation. Use Caution/Monitor. Concurrent use of medications with CNS depressant effects together with thalidomide should be avoided due to the risk for additive sedative effects.
  
  stiripentol will increase the level or effect of cetirizine by P-glycoprotein (MDR1) efflux transporter. Modify Therapy/Monitor Closely. Consider reducing the dose of P-glycoprotein (P-gp) substrates, if adverse reactions are experienced when administered concomitantly with stiripentol.

• tamsulosin

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

• tepotinib

  Serious - Use Alternative (1)tepotinib will increase the level or effect of cetirizine by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. If concomitant use unavoidable, reduce the P-gp substrate dosage if recommended in its approved product labeling.

• 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.

• theophylline

  Minor (1)theophylline increases levels of cetirizine by decreasing elimination. Minor/Significance Unknown.

• 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.

• tranylcypromine

  Contraindicated (1)tranylcypromine increases effects of pseudoephedrine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.Serious - Use Alternative (1)tranylcypromine increases effects of cetirizine by Other (see comment). Avoid or Use Alternate Drug. Comment: Tranylcypromine should not be administered in combination with antihistamines because of potential additive CNS depressant effects. MAO inhibitors also prolong and intensify anticholinergic effects of antihistamines.

• 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.

• tucatinib

  Monitor Closely (1)tucatinib will increase the level or effect of cetirizine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Consider reducing the dosage of P-gp substrates, where minimal concentration changes may lead to serious or life-threatening toxicities.

• vemurafenib

  Monitor Closely (1)vemurafenib increases levels of cetirizine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• 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.

• xylometazoline

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