promethazine (Rx)

Brand and Other Names:Phenergan, Phenadoz
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Dosing & Uses

AdultPediatric

Dosage Forms & Strengths

tablet

  • 12.5mg
  • 25mg
  • 50mg

suppository

  • 12.5mg
  • 25mg
  • 50mg

injectable solution

  • 25mg/mL
  • 50 mg/mL

syrup

  • 6.25mg/5mL

Allergic Conditions

PO/PR: 25 mg at bedtime or 12.5 mg before meals and at bedtime (dosage range, 6.25-12.5 mg q8hr)

IV/IM: 25 mg; may be repeated in 2 hours when necessary; switch to PO as soon as possible

Nausea & Vomiting

PO/PR: 12.5-25 mg q4-6hr PRN

IV/IM: 12.5-25 mg q4-6hr PRN

Motion Sickness

25 mg PO/PR 30-60 minutes before departure and q8-12hr PRN; on succeeding travel days, 25 mg PO/PR every morning and every evening

Preoperative Sedation

50 mg PO/PR on night before procedure or 25-50 mg IV/IM combined with reduced doses of analgesics and atropinelike drugs

Postoperative Sedation

25-50 mg IV/IM/PO/PR combined with reduced doses of analgesics and atropinelike drugs

Obstetric Sedation

25-50 mg IV/IM in early labor; may be increased to 25-75 mg q2-4hr after labor established; not to exceed two doses or up to 100 mg/day during labor

Dosage Forms & Strengths

tablet

  • 12.5mg
  • 25mg
  • 50mg

suppository

  • 12.5mg
  • 25mg
  • 50mg

injectable solution

  • 25mg/mL

syrup

  • 6.25mg/5mL

Allergic Conditions (Off-label)

<2 years old: Contraindicated

≥2 years old: 25 mg PO/PR at bedtime or 12.5 mg q6hr; alternatively, 6.25-12.5 mg PO/PR q8hr

Nausea & Vomiting

<2 years old: Contraindicated

≥2 years old: 0.25-1 mg/kg PO/PR q4-6hr PRN; not to exceed 25 mg  

Motion Sickness

<2 years: Contraindicated

≥2 years: 12.5-25 mg PO/PR administered 30-60 minutes before departure and q8-12hr PRN or 0.5 mg/kg PO q12hr PRN  

Succeeding days of travel: 12.5-25 mg twice daily (upon arising or before evening meals)

Sedation

<2 years: Contraindicated

≥2 years: 12.5-25 mg PO/IM/PR at bedtime

Preoperative Sedation

<2 years: Contraindicated

≥2 years: 1 mg/kg PO/PR with reduced dose of analgesic and appropriate dose of atropinelike drug  

Postoperative Sedation

<2 years: Contraindicated

≥2 years: 12.5-25 mg with reduced dose of analgesic and appropriate dose of atropinelike drug

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Interactions

Interaction Checker

and promethazine

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            Contraindicated (9)

            • disopyramide

              promethazine and disopyramide both increase QTc interval. Contraindicated.

            • ibutilide

              promethazine and ibutilide both increase QTc interval. Contraindicated.

            • indapamide

              promethazine and indapamide both increase QTc interval. Contraindicated.

            • metrizamide

              promethazine, metrizamide. Mechanism: unknown. Contraindicated. Risk of seizure. D/C phenothiazine 24h before admin. of metrizamide.

            • pentamidine

              promethazine and pentamidine both increase QTc interval. Contraindicated.

            • pimozide

              promethazine and pimozide both increase QTc interval. Contraindicated.

            • procainamide

              promethazine and procainamide both increase QTc interval. Contraindicated.

            • quinidine

              promethazine and quinidine both increase QTc interval. Contraindicated.

            • sotalol

              promethazine and sotalol both increase QTc interval. Contraindicated.

            Serious - Use Alternative (64)

            • abametapir

              abametapir will increase the level or effect of promethazine by affecting hepatic enzyme CYP2B6 metabolism. Avoid or Use Alternate Drug. For 2 weeks after abametapir application, avoid taking drugs that are CYP2D6 substrates. If not feasible, avoid use of abametapir.

            • amiodarone

              promethazine and amiodarone both increase QTc interval. Avoid or Use Alternate Drug.

            • apomorphine

              promethazine decreases effects of apomorphine by pharmacodynamic antagonism. Avoid or Use Alternate Drug.

            • arsenic trioxide

              promethazine and arsenic trioxide both increase QTc interval. Avoid or Use Alternate Drug.

            • artemether/lumefantrine

              promethazine and artemether/lumefantrine both increase QTc interval. Avoid or Use Alternate Drug.

            • bromocriptine

              promethazine decreases effects of bromocriptine by pharmacodynamic antagonism. Avoid or Use Alternate Drug.

            • cabergoline

              promethazine decreases effects of cabergoline by pharmacodynamic antagonism. Contraindicated.

            • calcium/magnesium/potassium/sodium oxybates

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

            • chlorpromazine

              chlorpromazine and promethazine both increase QTc interval. Avoid or Use Alternate Drug.

            • clarithromycin

              promethazine and clarithromycin both increase QTc interval. Avoid or Use Alternate Drug.

            • clomipramine

              promethazine and clomipramine both increase QTc interval. Avoid or Use Alternate Drug.

            • dacomitinib

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

            • dofetilide

              promethazine and dofetilide both increase QTc interval. Avoid or Use Alternate Drug.

            • dopamine

              promethazine decreases effects of dopamine by pharmacodynamic antagonism. Contraindicated.

            • dosulepin

              promethazine and dosulepin both increase QTc interval. Avoid or Use Alternate Drug.

            • dronedarone

              promethazine and dronedarone both increase QTc interval. Avoid or Use Alternate Drug.

            • droperidol

              promethazine and droperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • eluxadoline

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

            • epinephrine

              epinephrine and promethazine both increase QTc interval. Avoid or Use Alternate Drug.

            • epinephrine racemic

              epinephrine racemic and promethazine both increase QTc interval. Avoid or Use Alternate Drug.

            • erythromycin base

              promethazine and erythromycin base both increase QTc interval. Avoid or Use Alternate Drug.

            • erythromycin ethylsuccinate

              promethazine and erythromycin ethylsuccinate both increase QTc interval. Avoid or Use Alternate Drug.

            • erythromycin lactobionate

              promethazine and erythromycin lactobionate both increase QTc interval. Avoid or Use Alternate Drug.

            • erythromycin stearate

              promethazine and erythromycin stearate both increase QTc interval. Avoid or Use Alternate Drug.

            • fexinidazole

              fexinidazole will decrease the level or effect of promethazine by affecting hepatic enzyme CYP2B6 metabolism. Avoid or Use Alternate Drug. Coadministration may decrease plasma concentrations of CYP2B6 substrates owing to fexinidazole inducing CYP2B6.

            • fluconazole

              promethazine and fluconazole both increase QTc interval. Avoid or Use Alternate Drug.

            • fluoxetine

              fluoxetine will increase the level or effect of promethazine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

            • fluphenazine

              fluphenazine and promethazine both increase QTc interval. Avoid or Use Alternate Drug.

            • formoterol

              promethazine and formoterol both increase QTc interval. Avoid or Use Alternate Drug.

            • givosiran

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

            • haloperidol

              promethazine and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • isocarboxazid

              isocarboxazid increases effects of promethazine 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. .

            • itraconazole

              promethazine and itraconazole both increase QTc interval. Avoid or Use Alternate Drug.

            • ketoconazole

              promethazine and ketoconazole both increase QTc interval. Avoid or Use Alternate Drug.

            • levodopa

              promethazine decreases effects of levodopa by pharmacodynamic antagonism. Avoid or Use Alternate Drug.

            • lisuride

              promethazine decreases effects of lisuride by pharmacodynamic antagonism. Contraindicated.

            • lofepramine

              promethazine and lofepramine both increase QTc interval. Avoid or Use Alternate Drug.

            • lumefantrine

              promethazine and lumefantrine both increase QTc interval. Avoid or Use Alternate Drug.

            • mefloquine

              mefloquine increases toxicity of promethazine by QTc interval. Avoid or Use Alternate Drug. Mefloquine may enhance the QTc prolonging effect of high risk QTc prolonging agents.

            • methyldopa

              promethazine decreases effects of methyldopa by pharmacodynamic antagonism. Contraindicated.

            • methylene blue

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

            • metoclopramide intranasal

              promethazine, 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.

            • moxifloxacin

              promethazine and moxifloxacin both increase QTc interval. Avoid or Use Alternate Drug.

            • nilotinib

              promethazine and nilotinib both increase QTc interval. Avoid or Use Alternate Drug.

            • octreotide

              promethazine and octreotide both increase QTc interval. Avoid or Use Alternate Drug.

            • octreotide (Antidote)

              promethazine and octreotide (Antidote) both increase QTc interval. Avoid or Use Alternate Drug.

            • paroxetine

              paroxetine will increase the level or effect of promethazine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

            • perphenazine

              perphenazine and promethazine both increase QTc interval. Avoid or Use Alternate Drug.

            • pitolisant

              promethazine decreases effects of pitolisant by Other (see comment). Avoid or Use Alternate Drug. Comment: Pitolisant increases histamine levels in the brain; therefore, H1 receptor antagonists that cross the blood-brain barrier may reduce the efficacy of pitolisant.

            • pramipexole

              promethazine decreases effects of pramipexole by pharmacodynamic antagonism. Contraindicated.

            • prochlorperazine

              prochlorperazine and promethazine both increase QTc interval. Avoid or Use Alternate Drug.

            • promazine

              promazine and promethazine both increase QTc interval. Avoid or Use Alternate Drug.

            • quinidine

              quinidine, promethazine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Additive cardiac effects.

            • ropinirole

              promethazine decreases effects of ropinirole by pharmacodynamic antagonism. Contraindicated.

            • sodium oxybate

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

            • thioridazine

              promethazine and thioridazine both increase QTc interval. Avoid or Use Alternate Drug.

            • tranylcypromine

              tranylcypromine increases effects of promethazine 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. Combination of tranylcypromine and promethazine may result in additive hypotensive effects.

            • tretinoin

              promethazine, tretinoin. Mechanism: pharmacodynamic synergism. Avoid or Use Alternate Drug. Increased phototoxicity.

            • tretinoin topical

              promethazine, tretinoin topical. Mechanism: pharmacodynamic synergism. Avoid or Use Alternate Drug. Increased phototoxicity.

            • trifluoperazine

              promethazine and trifluoperazine both increase QTc interval. Avoid or Use Alternate Drug.

            • trimipramine

              promethazine and trimipramine both increase QTc interval. Avoid or Use Alternate Drug.

            • venlafaxine

              venlafaxine will increase the level or effect of promethazine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

            • yohimbe

              yohimbe decreases effects of promethazine by pharmacodynamic antagonism. Contraindicated.

            • ziprasidone

              promethazine and ziprasidone both increase QTc interval. Avoid or Use Alternate Drug.

            Monitor Closely (292)

            • abiraterone

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

            • aclidinium

              aclidinium decreases levels of promethazine by pharmacodynamic antagonism. Use Caution/Monitor.

              promethazine increases effects of aclidinium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • albiglutide

              promethazine, albiglutide. Other (see comment). Use Caution/Monitor. Comment: Phenothiazines may increase or decrease glucose levels, monitor therapy closely when these agents are concurrently administered.

            • albuterol

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

            • alfentanil

              promethazine and alfentanil both increase sedation. Use Caution/Monitor.

            • alprazolam

              promethazine and alprazolam both increase sedation. Use Caution/Monitor.

            • amifampridine

              promethazine 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.

            • amitriptyline

              promethazine and amitriptyline both increase QTc interval. Use Caution/Monitor.

              promethazine and amitriptyline both increase sedation. Use Caution/Monitor.

            • amobarbital

              promethazine and amobarbital both increase sedation. Use Caution/Monitor.

            • amoxapine

              promethazine and amoxapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              promethazine and amoxapine both increase QTc interval. Use Caution/Monitor.

              promethazine and amoxapine both increase sedation. Use Caution/Monitor.

            • anticholinergic/sedative combos

              anticholinergic/sedative combos decreases levels of promethazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              anticholinergic/sedative combos decreases levels of promethazine by pharmacodynamic antagonism. Use Caution/Monitor.

              promethazine increases effects of anticholinergic/sedative combos by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • apomorphine

              promethazine and apomorphine both increase sedation. Use Caution/Monitor.

            • arformoterol

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

            • aripiprazole

              aripiprazole and promethazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              promethazine and aripiprazole both increase sedation. Use Caution/Monitor.

              promethazine, aripiprazole. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • armodafinil

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

            • artemether/lumefantrine

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

            • asenapine

              promethazine, asenapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • atracurium

              atracurium decreases levels of promethazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              atracurium decreases levels of promethazine by pharmacodynamic antagonism. Use Caution/Monitor.

              promethazine increases effects of atracurium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • atropine

              atropine decreases levels of promethazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              atropine decreases levels of promethazine by pharmacodynamic antagonism. Use Caution/Monitor.

              promethazine increases effects of atropine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • atropine IV/IM

              promethazine increases effects of atropine IV/IM by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • azelastine

              azelastine and promethazine both increase sedation. Use Caution/Monitor.

            • azithromycin

              promethazine and azithromycin both increase QTc interval. Use Caution/Monitor.

            • baclofen

              promethazine and baclofen both increase sedation. Use Caution/Monitor.

            • belladonna alkaloids

              belladonna alkaloids decreases levels of promethazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              belladonna alkaloids decreases levels of promethazine by pharmacodynamic antagonism. Use Caution/Monitor.

              promethazine increases effects of belladonna alkaloids by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • belladonna and opium

              promethazine and belladonna and opium both increase sedation. Use Caution/Monitor.

              belladonna and opium decreases levels of promethazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              belladonna and opium decreases levels of promethazine by pharmacodynamic antagonism. Use Caution/Monitor.

              promethazine increases effects of belladonna and opium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • benperidol

              benperidol and promethazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              promethazine and benperidol both increase sedation. Use Caution/Monitor.

            • benzphetamine

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

              promethazine, benzphetamine. 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.

            • benztropine

              promethazine increases effects of benztropine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic adverse effects may be seen with concurrent use. .

            • brexanolone

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

            • brompheniramine

              brompheniramine and promethazine both increase sedation. Use Caution/Monitor.

            • buprenorphine

              promethazine and buprenorphine both increase sedation. Use Caution/Monitor.

            • buprenorphine buccal

              promethazine and buprenorphine buccal both increase sedation. Use Caution/Monitor.

            • bupropion

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

            • butabarbital

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

            • butalbital

              promethazine and butalbital both increase sedation. Use Caution/Monitor.

            • butorphanol

              promethazine and butorphanol both increase sedation. Use Caution/Monitor.

            • caffeine

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

            • carbinoxamine

              carbinoxamine and promethazine both increase sedation. Use Caution/Monitor.

            • cariprazine

              promethazine, cariprazine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • carisoprodol

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

            • cenobamate

              cenobamate will decrease the level or effect of promethazine by affecting hepatic enzyme CYP2B6 metabolism. Modify Therapy/Monitor Closely. Increase dose of CYP2B6 substrate, as needed, when coadministered with cenobamate.

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

            • chloral hydrate

              promethazine and chloral hydrate both increase sedation. Use Caution/Monitor.

            • chlordiazepoxide

              promethazine and chlordiazepoxide both increase sedation. Use Caution/Monitor.

            • chlorpheniramine

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

            • chlorpromazine

              chlorpromazine and promethazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              promethazine and chlorpromazine both increase sedation. Use Caution/Monitor.

            • chlorzoxazone

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

            • cigarette smoking

              cigarette smoking decreases levels of promethazine by increasing metabolism. Use Caution/Monitor. Interaction mainly seen w/chlorpromazine & thioridazine, but may occur w/other phenothiazines.

            • cinnarizine

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

            • cisatracurium

              cisatracurium decreases levels of promethazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              cisatracurium decreases levels of promethazine by pharmacodynamic antagonism. Use Caution/Monitor.

              promethazine increases effects of cisatracurium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • citalopram

              citalopram and promethazine both increase serotonin levels. Use Caution/Monitor. Combination may increase risk of serotonin syndrome or neuroleptic malignant syndrome-like reactions.

            • clemastine

              clemastine and promethazine both increase sedation. Use Caution/Monitor.

            • clobazam

              clobazam will increase the level or effect of promethazine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Lower doses of drugs metabolized by CYP2D6 may be required when used concomitantly.

              promethazine, 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

              promethazine and clomipramine both increase sedation. Use Caution/Monitor.

            • clonazepam

              promethazine and clonazepam both increase sedation. Use Caution/Monitor.

            • clonidine

              clonidine, promethazine. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Additive hypotensive effects; potential delirium.

            • clorazepate

              promethazine and clorazepate both increase sedation. Use Caution/Monitor.

            • clozapine

              clozapine and promethazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              promethazine and clozapine both increase sedation. Use Caution/Monitor.

              promethazine, clozapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • codeine

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

            • cyclizine

              cyclizine and promethazine both increase sedation. Use Caution/Monitor.

              cyclizine decreases levels of promethazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              cyclizine decreases levels of promethazine by pharmacodynamic antagonism. Use Caution/Monitor.

              promethazine increases effects of cyclizine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • cyclobenzaprine

              promethazine and cyclobenzaprine both increase sedation. Use Caution/Monitor.

              cyclobenzaprine decreases levels of promethazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              cyclobenzaprine decreases levels of promethazine by pharmacodynamic antagonism. Use Caution/Monitor.

              promethazine increases effects of cyclobenzaprine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • cyproheptadine

              cyproheptadine and promethazine both increase sedation. Use Caution/Monitor.

            • dantrolene

              promethazine and dantrolene both increase sedation. Use Caution/Monitor.

            • darifenacin

              darifenacin decreases levels of promethazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              darifenacin decreases levels of promethazine by pharmacodynamic antagonism. Use Caution/Monitor.

              promethazine increases effects of darifenacin by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • dasatinib

              promethazine and dasatinib both increase QTc interval. Modify Therapy/Monitor Closely.

            • desflurane

              desflurane and promethazine both increase sedation. Use Caution/Monitor.

            • desipramine

              promethazine and desipramine both increase QTc interval. Use Caution/Monitor.

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

            • desvenlafaxine

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

            • deutetrabenazine

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

            • dexchlorpheniramine

              dexchlorpheniramine and promethazine both increase sedation. Use Caution/Monitor.

            • dexfenfluramine

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

              promethazine, dexfenfluramine. 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.

            • dexmedetomidine

              promethazine and dexmedetomidine both increase sedation. Use Caution/Monitor.

            • dexmethylphenidate

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

              promethazine, dexmethylphenidate. 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.

            • dextroamphetamine

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

              promethazine, dextroamphetamine. 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.

            • dextromoramide

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

            • diamorphine

              promethazine and diamorphine both increase sedation. Use Caution/Monitor.

            • diazepam

              promethazine and diazepam both increase sedation. Use Caution/Monitor.

            • diazepam intranasal

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

            • dicyclomine

              dicyclomine decreases levels of promethazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              dicyclomine decreases levels of promethazine by pharmacodynamic antagonism. Use Caution/Monitor.

              promethazine increases effects of dicyclomine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • diethylpropion

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

              promethazine, diethylpropion. 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.

            • difenoxin hcl

              promethazine and difenoxin hcl both increase sedation. Use Caution/Monitor.

            • dimenhydrinate

              dimenhydrinate and promethazine both increase sedation. Use Caution/Monitor.

            • diphenhydramine

              diphenhydramine and promethazine both increase sedation. Use Caution/Monitor.

              diphenhydramine decreases levels of promethazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              diphenhydramine decreases levels of promethazine by pharmacodynamic antagonism. Use Caution/Monitor.

              promethazine increases effects of diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • diphenoxylate hcl

              promethazine and diphenoxylate hcl both increase sedation. Use Caution/Monitor.

            • dipipanone

              promethazine and dipipanone both increase sedation. Use Caution/Monitor.

            • dobutamine

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

              promethazine, dobutamine. 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.

            • dolasetron

              promethazine and dolasetron both increase QTc interval. Modify Therapy/Monitor Closely.

            • dopamine

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

              promethazine, dopamine. 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.

            • dopexamine

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

            • dosulepin

              promethazine and dosulepin both increase sedation. Use Caution/Monitor.

            • doxepin

              promethazine and doxepin both increase QTc interval. Use Caution/Monitor.

              promethazine and doxepin both increase sedation. Use Caution/Monitor.

            • doxylamine

              promethazine and doxylamine both increase sedation. Use Caution/Monitor.

            • droperidol

              droperidol and promethazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

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

            • eliglustat

              eliglustat increases levels of promethazine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Monitor therapeutic drug concentrations, as indicated, or consider reducing the dosage of the concomitant drug and titrate to clinical effect.

            • elvitegravir/cobicistat/emtricitabine/tenofovir DF

              elvitegravir/cobicistat/emtricitabine/tenofovir DF increases levels of promethazine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Cobicistat is a CYP2D6 inhibitor; caution with CYP2D6 substrates for which elevated plasma concentrations are associated with serious and/or life-threatening events.

            • ephedrine

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

              promethazine, ephedrine. 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.

            • epinephrine

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

              promethazine, epinephrine. 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 decreases effects of epinephrine by pharmacodynamic antagonism. Use Caution/Monitor. Block pressor response to epinephrine, which may result in severe hypotension and tachycardia.

            • epinephrine racemic

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

              promethazine decreases effects of epinephrine racemic by pharmacodynamic antagonism. Use Caution/Monitor. Block pressor response to epinephrine, which may result in severe hypotension and tachycardia.

            • esketamine intranasal

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

            • estazolam

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

            • ethanol

              promethazine and ethanol both increase sedation. Use Caution/Monitor.

            • etomidate

              etomidate and promethazine both increase sedation. Use Caution/Monitor.

            • fedratinib

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

            • fenfluramine

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

              promethazine, fenfluramine. 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.

            • fentanyl

              fentanyl, promethazine. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of fentanyl with anticholinergics may increase risk for urinary retention and/or severe constipation, which may lead to paralytic ileus.

            • fentanyl intranasal

              fentanyl intranasal, promethazine. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of fentanyl with anticholinergics may increase risk for urinary retention and/or severe constipation, which may lead to paralytic ileus.

            • fentanyl transdermal

              fentanyl transdermal, promethazine. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of fentanyl with anticholinergics may increase risk for urinary retention and/or severe constipation, which may lead to paralytic ileus.

            • fentanyl transmucosal

              fentanyl transmucosal, promethazine. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of fentanyl with anticholinergics may increase risk for urinary retention and/or severe constipation, which may lead to paralytic ileus.

            • fesoterodine

              fesoterodine decreases levels of promethazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              fesoterodine decreases levels of promethazine by pharmacodynamic antagonism. Use Caution/Monitor.

              promethazine increases effects of fesoterodine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • flavoxate

              flavoxate decreases levels of promethazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              flavoxate decreases levels of promethazine by pharmacodynamic antagonism. Use Caution/Monitor.

              promethazine increases effects of flavoxate by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • flecainide

              promethazine and flecainide both increase QTc interval. Modify Therapy/Monitor Closely.

            • flibanserin

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

            • fluoxetine

              promethazine and fluoxetine both increase QTc interval. Use Caution/Monitor.

            • fluphenazine

              fluphenazine and promethazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              promethazine and fluphenazine both increase sedation. Use Caution/Monitor.

              promethazine, fluphenazine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • flurazepam

              promethazine and flurazepam both increase sedation. Use Caution/Monitor.

            • fluvoxamine

              fluvoxamine and promethazine both increase QTc interval. Use Caution/Monitor.

            • formoterol

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

            • foscarnet

              promethazine and foscarnet both increase QTc interval. Modify Therapy/Monitor Closely.

            • gabapentin

              gabapentin, promethazine. 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, promethazine. 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.

            • glycopyrrolate

              promethazine increases effects of glycopyrrolate by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • glycopyrrolate inhaled

              glycopyrrolate inhaled decreases levels of promethazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              glycopyrrolate inhaled decreases levels of promethazine by pharmacodynamic antagonism. Use Caution/Monitor.

              promethazine increases effects of glycopyrrolate inhaled by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • glycopyrronium tosylate topical

              glycopyrronium tosylate topical, promethazine. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration of glycopyrronium tosylate topical with other anticholinergic medications may result in additive anticholinergic adverse effects.

            • gotu kola

              gotu kola increases effects of promethazine by pharmacodynamic synergism. Use Caution/Monitor. May enhance CNS depression.

            • guanfacine

              guanfacine, promethazine. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Additive hypotensive effects; potential delirium.

            • haloperidol

              haloperidol and promethazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              promethazine and haloperidol both increase sedation. Use Caution/Monitor.

              promethazine, haloperidol. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • hawthorn

              hawthorn increases effects of promethazine by pharmacodynamic synergism. Use Caution/Monitor. May enhance CNS depression.

            • henbane

              henbane decreases levels of promethazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              henbane decreases levels of promethazine by pharmacodynamic antagonism. Use Caution/Monitor.

              promethazine increases effects of henbane by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • homatropine

              homatropine decreases levels of promethazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              homatropine decreases levels of promethazine by pharmacodynamic antagonism. Use Caution/Monitor.

              promethazine increases effects of homatropine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • hops

              hops increases effects of promethazine by pharmacodynamic synergism. Use Caution/Monitor. May enhance CNS depression.

            • hyaluronidase

              promethazine 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.

            • hydromorphone

              promethazine and hydromorphone both increase sedation. Use Caution/Monitor.

            • hydroxyzine

              hydroxyzine and promethazine both increase sedation. Use Caution/Monitor.

            • hyoscyamine

              hyoscyamine decreases levels of promethazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              hyoscyamine decreases levels of promethazine by pharmacodynamic antagonism. Use Caution/Monitor.

              promethazine increases effects of hyoscyamine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • hyoscyamine spray

              promethazine increases effects of hyoscyamine spray by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • iloperidone

              iloperidone and promethazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              promethazine and iloperidone both increase QTc interval. Modify Therapy/Monitor Closely.

              promethazine and iloperidone both increase sedation. Use Caution/Monitor.

              promethazine, iloperidone. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • imipramine

              promethazine and imipramine both increase QTc interval. Use Caution/Monitor.

              promethazine and imipramine both increase sedation. Use Caution/Monitor.

            • incobotulinumtoxinA

              promethazine, incobotulinumtoxinA. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Use of anticholinergic drugs after administration of botulinum toxin-containing products may potentiate systemic anticholinergic effects.

            • ipratropium

              ipratropium decreases levels of promethazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              ipratropium decreases levels of promethazine by pharmacodynamic antagonism. Use Caution/Monitor.

              promethazine increases effects of ipratropium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • isoproterenol

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

              promethazine, isoproterenol. 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.

            • kava

              kava increases effects of promethazine by pharmacodynamic synergism. Use Caution/Monitor. May enhance CNS depression.

            • ketamine

              ketamine and promethazine both increase sedation. Use Caution/Monitor.

            • ketotifen, ophthalmic

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

            • lapatinib

              promethazine and lapatinib both increase QTc interval. Modify Therapy/Monitor Closely.

            • lasmiditan

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

            • lemborexant

              lemborexant will decrease the level or effect of promethazine by affecting hepatic enzyme CYP2B6 metabolism. Modify Therapy/Monitor Closely. Monitor CYP2B6 substrate for adequate clinical response. Consider increasing the CYP2B6 substrate dose according to specific prescribing recommendations.

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

            • levalbuterol

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

            • levofloxacin

              promethazine and levofloxacin both increase QTc interval. Modify Therapy/Monitor Closely.

            • levorphanol

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

            • liraglutide

              promethazine, liraglutide. Other (see comment). Use Caution/Monitor. Comment: Phenothiazines may increase or decrease glucose levels, monitor therapy closely when these agents are concurrently administered.

            • lisdexamfetamine

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

              promethazine, lisdexamfetamine. 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.

            • lithium

              lithium, promethazine. Other (see comment). Use Caution/Monitor. Comment: Risk of neurotoxicity. Multiple mechanisms involved.

            • lofepramine

              promethazine and lofepramine both increase sedation. Use Caution/Monitor.

            • lofexidine

              promethazine and lofexidine both increase sedation. Use Caution/Monitor.

            • loprazolam

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

            • lorazepam

              promethazine and lorazepam both increase sedation. Use Caution/Monitor.

            • lorcaserin

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

            • lormetazepam

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

            • loxapine

              loxapine and promethazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              promethazine and loxapine both increase sedation. Use Caution/Monitor.

              promethazine, loxapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • loxapine inhaled

              loxapine inhaled and promethazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              promethazine and loxapine inhaled both increase sedation. Use Caution/Monitor.

              promethazine, loxapine inhaled. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • lumacaftor/ivacaftor

              lumacaftor/ivacaftor, promethazine. affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor. In vitro studies suggest that lumacaftor may induce and ivacaftor may inhibit CYP2B6 substrates. .

            • lumefantrine

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

            • lurasidone

              lurasidone increases effects of promethazine by Other (see comment). Use Caution/Monitor. Comment: Potential for increased risk of hypotension with concurrent use. Monitor blood pressure and adjust dose of antihypertensive agent as needed.; potendial for additive CNS effects .

              promethazine, lurasidone. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • maprotiline

              promethazine and maprotiline both increase QTc interval. Use Caution/Monitor.

              promethazine and maprotiline both increase sedation. Use Caution/Monitor.

            • marijuana

              promethazine and marijuana both increase sedation. Use Caution/Monitor.

            • meclizine

              meclizine decreases levels of promethazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              meclizine decreases levels of promethazine by pharmacodynamic antagonism. Use Caution/Monitor.

              promethazine increases effects of meclizine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • melatonin

              promethazine and melatonin both increase sedation. Use Caution/Monitor.

            • meperidine

              promethazine and meperidine both increase sedation. Use Caution/Monitor.

            • meprobamate

              promethazine and meprobamate both increase sedation. Use Caution/Monitor.

            • metaproterenol

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

            • metaxalone

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

            • metformin

              promethazine decreases effects of metformin by pharmacodynamic antagonism. Use Caution/Monitor. Patient should be closely observed for loss of blood glucose control; when drugs are withdrawn from a patient receiving metformin, patient should be observed closely for hypoglycemia.

            • methadone

              promethazine and methadone both increase QTc interval. Modify Therapy/Monitor Closely.

              promethazine and methadone both increase sedation. Use Caution/Monitor.

            • methamphetamine

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

              promethazine, methamphetamine. 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.

            • methocarbamol

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

            • methoxsalen

              methoxsalen, promethazine. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Additive photosensitizing effects.

            • methscopolamine

              methscopolamine decreases levels of promethazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              methscopolamine decreases levels of promethazine by pharmacodynamic antagonism. Use Caution/Monitor.

              promethazine increases effects of methscopolamine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • methylenedioxymethamphetamine

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

              promethazine, methylenedioxymethamphetamine. 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.

            • methylphenidate

              promethazine, methylphenidate. 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.

            • metoclopramide

              promethazine and metoclopramide both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

            • midazolam

              promethazine and midazolam both increase sedation. Use Caution/Monitor.

            • midazolam intranasal

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

            • midodrine

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

              promethazine, midodrine. 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.

            • mifepristone

              mifepristone will increase the level or effect of promethazine by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor.

            • mirabegron

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

            • mirtazapine

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

            • modafinil

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

            • molindone

              promethazine, molindone. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • morphine

              promethazine and morphine both increase sedation. Use Caution/Monitor.

            • motherwort

              promethazine and motherwort both increase sedation. Use Caution/Monitor.

            • moxonidine

              promethazine and moxonidine both increase sedation. Use Caution/Monitor.

            • nabilone

              promethazine and nabilone both increase sedation. Use Caution/Monitor.

            • nalbuphine

              promethazine and nalbuphine both increase sedation. Use Caution/Monitor.

            • norepinephrine

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

              promethazine, norepinephrine. 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.

            • nortriptyline

              promethazine and nortriptyline both increase QTc interval. Use Caution/Monitor.

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

            • ofloxacin

              promethazine and ofloxacin both increase QTc interval. Modify Therapy/Monitor Closely.

            • olanzapine

              olanzapine and promethazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              promethazine and olanzapine both increase sedation. Use Caution/Monitor.

              promethazine, olanzapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • onabotulinumtoxinA

              onabotulinumtoxinA decreases levels of promethazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              onabotulinumtoxinA decreases levels of promethazine by pharmacodynamic antagonism. Use Caution/Monitor.

              promethazine increases effects of onabotulinumtoxinA by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • opium tincture

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

            • orphenadrine

              promethazine and orphenadrine both increase sedation. Use Caution/Monitor.

            • oxazepam

              promethazine and oxazepam both increase sedation. Use Caution/Monitor.

            • oxybutynin

              oxybutynin decreases levels of promethazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              oxybutynin decreases levels of promethazine by pharmacodynamic antagonism. Use Caution/Monitor.

              promethazine increases effects of oxybutynin by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • oxybutynin topical

              oxybutynin topical decreases levels of promethazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              oxybutynin topical decreases levels of promethazine by pharmacodynamic antagonism. Use Caution/Monitor.

              promethazine increases effects of oxybutynin topical by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • oxybutynin transdermal

              oxybutynin transdermal decreases levels of promethazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              oxybutynin transdermal decreases levels of promethazine by pharmacodynamic antagonism. Use Caution/Monitor.

              promethazine increases effects of oxybutynin transdermal by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • oxycodone

              promethazine and oxycodone both increase sedation. Use Caution/Monitor.

            • oxymorphone

              promethazine and oxymorphone both increase sedation. Use Caution/Monitor.

            • paliperidone

              paliperidone and promethazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              promethazine and paliperidone both increase QTc interval. Modify Therapy/Monitor Closely.

              promethazine and paliperidone both increase sedation. Use Caution/Monitor.

              promethazine, paliperidone. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • pancuronium

              pancuronium decreases levels of promethazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              pancuronium decreases levels of promethazine by pharmacodynamic antagonism. Use Caution/Monitor.

              promethazine increases effects of pancuronium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • papaveretum

              promethazine and papaveretum both increase sedation. Use Caution/Monitor.

            • papaverine

              promethazine and papaverine both increase sedation. Use Caution/Monitor.

            • paroxetine

              promethazine and paroxetine both increase QTc interval. Use Caution/Monitor.

            • passion flower

              passion flower increases effects of promethazine by pharmacodynamic synergism. Use Caution/Monitor. May enhance CNS depression.

            • pazopanib

              promethazine and pazopanib both increase QTc interval. Use Caution/Monitor.

            • peginterferon alfa 2b

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

            • pentazocine

              promethazine and pentazocine both increase sedation. Use Caution/Monitor.

            • pentobarbital

              promethazine and pentobarbital both increase sedation. Use Caution/Monitor.

            • perampanel

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

            • perphenazine

              perphenazine and promethazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

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

              promethazine, perphenazine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • phendimetrazine

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

              promethazine, phendimetrazine. 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.

            • phenelzine

              phenelzine increases effects of promethazine 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. .

            • phenobarbital

              promethazine and phenobarbital both increase sedation. Use Caution/Monitor.

            • phentermine

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

              promethazine, phentermine. 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.

            • phenylephrine

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

              promethazine, phenylephrine. 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.

            • phenylephrine PO

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

              promethazine, phenylephrine PO. 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.

            • pholcodine

              promethazine and pholcodine both increase sedation. Use Caution/Monitor.

            • pimavanserin

              promethazine, pimavanserin. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • pimozide

              pimozide and promethazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              promethazine and pimozide both increase sedation. Use Caution/Monitor.

              promethazine, pimozide. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • pirbuterol

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

            • porfimer

              promethazine, porfimer. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Enhanced photosensitivity.

            • posaconazole

              promethazine and posaconazole both increase QTc interval. Modify Therapy/Monitor Closely.

            • pralidoxime

              pralidoxime decreases levels of promethazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              pralidoxime decreases levels of promethazine by pharmacodynamic antagonism. Use Caution/Monitor.

              promethazine increases effects of pralidoxime by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • pregabalin

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

            • primidone

              promethazine and primidone both increase sedation. Use Caution/Monitor.

            • procarbazine

              procarbazine, promethazine. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Excessive sedation.

            • prochlorperazine

              prochlorperazine and promethazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              promethazine and prochlorperazine both increase sedation. Use Caution/Monitor.

            • propafenone

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

            • propantheline

              propantheline decreases levels of promethazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              propantheline decreases levels of promethazine by pharmacodynamic antagonism. Use Caution/Monitor.

              promethazine increases effects of propantheline by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • propofol

              propofol and promethazine both increase sedation. Use Caution/Monitor.

            • propylhexedrine

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

              promethazine, propylhexedrine. 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.

            • protriptyline

              promethazine and protriptyline both increase QTc interval. Use Caution/Monitor.

              promethazine and protriptyline both increase sedation. Use Caution/Monitor.

            • pseudoephedrine

              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.

            • quazepam

              promethazine and quazepam both increase sedation. Use Caution/Monitor.

            • quetiapine

              promethazine and quetiapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              promethazine and quetiapine both increase sedation. Use Caution/Monitor.

              promethazine, quetiapine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • quinidine

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

            • ramelteon

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

            • ranolazine

              promethazine and ranolazine both increase QTc interval. Modify Therapy/Monitor Closely.

            • rapacuronium

              rapacuronium decreases levels of promethazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              rapacuronium decreases levels of promethazine by pharmacodynamic antagonism. Use Caution/Monitor.

              promethazine increases effects of rapacuronium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • risperidone

              promethazine and risperidone both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              promethazine and risperidone both increase QTc interval. Modify Therapy/Monitor Closely.

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

              promethazine, risperidone. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • rocuronium

              rocuronium decreases levels of promethazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              rocuronium decreases levels of promethazine by pharmacodynamic antagonism. Use Caution/Monitor.

              promethazine increases effects of rocuronium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • rolapitant

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

            • salmeterol

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

            • scopolamine

              scopolamine decreases levels of promethazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              scopolamine decreases levels of promethazine by pharmacodynamic antagonism. Use Caution/Monitor.

              promethazine increases effects of scopolamine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • scullcap

              promethazine and scullcap both increase sedation. Use Caution/Monitor.

            • secobarbital

              promethazine and secobarbital both increase sedation. Use Caution/Monitor.

            • sevoflurane

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

            • shepherd's purse

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

            • smoking

              smoking decreases levels of promethazine by increasing metabolism. Use Caution/Monitor. Interaction mainly seen w/chlorpromazine & thioridazine, but may occur w/other phenothiazines.

            • solifenacin

              solifenacin decreases levels of promethazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              solifenacin decreases levels of promethazine by pharmacodynamic antagonism. Use Caution/Monitor.

              promethazine increases effects of solifenacin by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • stiripentol

              stiripentol, promethazine. affecting hepatic enzyme CYP2B6 metabolism. Modify Therapy/Monitor Closely. Stiripentol is a CYP2B6 inhibitor and inducer. Monitor CYP2B6 substrates coadministered with stiripentol for increased or decreased effects. CYP2B6 substrates may require dosage adjustment.

              stiripentol, promethazine. Either increases effects of the other by sedation. Use Caution/Monitor. Concomitant use stiripentol with other CNS depressants, including alcohol, may increase the risk of sedation and somnolence.

            • sufentanil

              promethazine and sufentanil both increase sedation. Use Caution/Monitor.

            • sulfamethoxazole

              promethazine and sulfamethoxazole both increase QTc interval. Modify Therapy/Monitor Closely.

            • tapentadol

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

            • telavancin

              promethazine and telavancin both increase QTc interval. Modify Therapy/Monitor Closely.

            • temazepam

              promethazine and temazepam both increase sedation. Use Caution/Monitor.

            • terbinafine

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

            • terbutaline

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

            • tetrabenazine

              promethazine and tetrabenazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Modify Therapy/Monitor Closely.

            • thioridazine

              promethazine and thioridazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

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

            • thiothixene

              promethazine and thiothixene both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              promethazine and thiothixene both increase sedation. Use Caution/Monitor.

              promethazine, thiothixene. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • tiotropium

              tiotropium decreases levels of promethazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              tiotropium decreases levels of promethazine by pharmacodynamic antagonism. Use Caution/Monitor.

              promethazine increases effects of tiotropium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • tobacco use

              tobacco use decreases levels of promethazine by increasing metabolism. Use Caution/Monitor. Interaction mainly seen w/chlorpromazine & thioridazine, but may occur w/other phenothiazines.

            • tolterodine

              tolterodine decreases levels of promethazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              tolterodine decreases levels of promethazine by pharmacodynamic antagonism. Use Caution/Monitor.

              promethazine increases effects of tolterodine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • topiramate

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

            • tramadol

              promethazine and tramadol both increase sedation. Use Caution/Monitor.

            • trazodone

              promethazine and trazodone both increase QTc interval. Use Caution/Monitor.

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

            • triazolam

              promethazine and triazolam both increase sedation. Use Caution/Monitor.

            • triclofos

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

            • trifluoperazine

              promethazine and trifluoperazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              promethazine and trifluoperazine both increase sedation. Use Caution/Monitor.

              promethazine, trifluoperazine. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • trihexyphenidyl

              trihexyphenidyl decreases levels of promethazine by pharmacodynamic antagonism. Use Caution/Monitor.

              promethazine increases effects of trihexyphenidyl by pharmacodynamic synergism. Use Caution/Monitor. Potential for additive anticholinergic effects.

            • trimethoprim

              promethazine and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

            • trimipramine

              promethazine and trimipramine both increase sedation. Use Caution/Monitor.

            • triprolidine

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

            • tropisetron

              promethazine and tropisetron both increase QTc interval. Modify Therapy/Monitor Closely.

            • trospium chloride

              trospium chloride decreases levels of promethazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              trospium chloride decreases levels of promethazine by pharmacodynamic antagonism. Use Caution/Monitor.

              promethazine increases effects of trospium chloride by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • valerian

              valerian increases effects of promethazine by pharmacodynamic synergism. Use Caution/Monitor. May enhance CNS depression.

            • vecuronium

              vecuronium decreases levels of promethazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              vecuronium decreases levels of promethazine by pharmacodynamic antagonism. Use Caution/Monitor.

              promethazine increases effects of vecuronium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • venlafaxine

              promethazine and venlafaxine both increase QTc interval. Use Caution/Monitor.

            • voriconazole

              promethazine and voriconazole both increase QTc interval. Modify Therapy/Monitor Closely.

            • xylometazoline

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

              promethazine, xylometazoline. 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.

            • yohimbine

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

              promethazine, yohimbine. 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.

            • ziconotide

              promethazine and ziconotide both increase sedation. Use Caution/Monitor.

            • ziprasidone

              promethazine and ziprasidone both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              promethazine and ziprasidone both increase sedation. Use Caution/Monitor.

              promethazine, ziprasidone. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • zotepine

              promethazine and zotepine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              promethazine and zotepine both increase sedation. Use Caution/Monitor.

            Minor (65)

            • amiodarone

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

            • amitriptyline

              amitriptyline, promethazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects.

              amitriptyline, promethazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.

            • amoxapine

              amoxapine, promethazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects.

              amoxapine, promethazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.

              promethazine, amoxapine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.

            • asenapine

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

            • ashwagandha

              ashwagandha increases effects of promethazine by pharmacodynamic synergism. Minor/Significance Unknown. May enhance CNS depression.

            • atropine

              promethazine increases toxicity of atropine by unknown mechanism. Minor/Significance Unknown.

            • atropine IV/IM

              promethazine increases toxicity of atropine IV/IM by unknown mechanism. Minor/Significance Unknown.

            • benazepril

              promethazine increases effects of benazepril by unspecified interaction mechanism. Minor/Significance Unknown. Enhanced hypotensive effects.

            • brimonidine

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

            • bupropion

              promethazine increases toxicity of bupropion by unspecified interaction mechanism. Minor/Significance Unknown. May lower seizure threshold; keep bupropion dose as low as possible.

            • captopril

              promethazine increases effects of captopril by unspecified interaction mechanism. Minor/Significance Unknown.

            • celecoxib

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

            • chasteberry

              chasteberry decreases effects of promethazine by pharmacodynamic antagonism. Minor/Significance Unknown. (Theoretical interaction).

            • chloroquine

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

              chloroquine increases levels of promethazine by decreasing metabolism. Minor/Significance Unknown.

            • cimetidine

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

            • clomipramine

              clomipramine, promethazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects.

              clomipramine, promethazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.

            • darifenacin

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

            • desipramine

              desipramine, promethazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects.

              desipramine, promethazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.

            • diphenhydramine

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

            • doxepin

              doxepin, promethazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects.

              doxepin, promethazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.

            • dronedarone

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

            • duloxetine

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

            • enalapril

              promethazine increases effects of enalapril by unspecified interaction mechanism. Minor/Significance Unknown.

            • ethanol

              ethanol, promethazine. Either increases toxicity of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive CNS depression.

            • eucalyptus

              promethazine and eucalyptus both increase sedation. Minor/Significance Unknown.

            • famciclovir

              promethazine, famciclovir. aldehyde dehydrogenase inhibition. Minor/Significance Unknown. The conversion of 6-deoxy penciclovir to penciclovir is catalyzed by aldehyde oxidase. Interactions with other drugs metabolized by this enzyme and/or inhibiting this enzyme could potentially occur. Clinical interaction studies of famciclovir with promethazine did not show relevant effects on the formation of penciclovir.

            • fosinopril

              promethazine increases effects of fosinopril by unspecified interaction mechanism. Minor/Significance Unknown.

            • glycopyrrolate

              promethazine increases toxicity of glycopyrrolate by unknown mechanism. Minor/Significance Unknown.

            • glycopyrrolate inhaled

              promethazine increases toxicity of glycopyrrolate inhaled by unknown mechanism. Minor/Significance Unknown.

            • haloperidol

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

            • imatinib

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

            • imidapril

              promethazine increases effects of imidapril by unspecified interaction mechanism. Minor/Significance Unknown.

            • imipramine

              imipramine, promethazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects.

              imipramine, promethazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.

            • lisinopril

              promethazine increases effects of lisinopril by unspecified interaction mechanism. Minor/Significance Unknown.

            • lofepramine

              lofepramine, promethazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects.

              lofepramine, promethazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.

            • maprotiline

              maprotiline, promethazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects.

              maprotiline, promethazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.

            • maraviroc

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

            • marijuana

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

            • metyrapone

              promethazine decreases effects of metyrapone by unspecified interaction mechanism. Minor/Significance Unknown.

            • metyrosine

              metyrosine increases toxicity of promethazine by pharmacodynamic synergism. Minor/Significance Unknown. Increased extrapyramidal symptoms.

            • moexipril

              promethazine increases effects of moexipril by unspecified interaction mechanism. Minor/Significance Unknown.

            • nettle

              nettle increases effects of promethazine by pharmacodynamic synergism. Minor/Significance Unknown. (High dose nettle; theoretical interaction) May enhance CNS depression.

            • nilotinib

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

            • nortriptyline

              nortriptyline, promethazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects.

              nortriptyline, promethazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.

            • oxybutynin

              oxybutynin increases toxicity of promethazine by unspecified interaction mechanism. Minor/Significance Unknown.

            • oxybutynin topical

              oxybutynin topical increases toxicity of promethazine by unspecified interaction mechanism. Minor/Significance Unknown.

            • oxybutynin transdermal

              oxybutynin transdermal increases toxicity of promethazine by unspecified interaction mechanism. Minor/Significance Unknown.

            • parecoxib

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

            • perindopril

              promethazine increases effects of perindopril by unspecified interaction mechanism. Minor/Significance Unknown.

            • perphenazine

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

            • protriptyline

              protriptyline, promethazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects.

              protriptyline, promethazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.

            • pyrimethamine

              pyrimethamine increases levels of promethazine by decreasing metabolism. Minor/Significance Unknown.

            • quinacrine

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

            • quinapril

              promethazine increases effects of quinapril by unspecified interaction mechanism. Minor/Significance Unknown.

            • ramipril

              promethazine increases effects of ramipril by unspecified interaction mechanism. Minor/Significance Unknown.

            • ranolazine

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

            • ritonavir

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

            • sage

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

            • sertraline

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

            • Siberian ginseng

              Siberian ginseng increases effects of promethazine by pharmacodynamic synergism. Minor/Significance Unknown. May enhance CNS depression.

            • thioridazine

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

            • tipranavir

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

            • trandolapril

              promethazine increases effects of trandolapril by unspecified interaction mechanism. Minor/Significance Unknown.

            • trazodone

              trazodone, promethazine. Either increases toxicity of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive hypotensive effects.

              trazodone, promethazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects.

            • trimipramine

              trimipramine, promethazine. Either increases levels of the other by decreasing metabolism. Minor/Significance Unknown. Additive anticholinergic effects.

              trimipramine, promethazine. Either increases levels of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.

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            Adverse Effects

            Frequency Not Defined

            Sedation

            Confusion

            Disorientation

            Blurred vision

            Hallucinations

            Dystonias

            Catatonic states

            Euphoria

            Excitation

            Extrapyramidal symptoms

            Tachycardia

            Bradycardia

            Leukopenia (rare)

            Agranulocytosis (rare)

            Obstructive jaundice

            Photosensitivity

            Dry mouth

            Angioneurotic edema

            Tardive dyskinesia

            Urticaria

            Xerostomia

            Impotence

            Urinary retention

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            Warnings

            Black Box Warnings

            IV administration can cause severe tissue injury, including burning, gangrene, or thrombophlebitis, necessitating fasciotomy, skin graft, or amputation

            Severe tissue injury can occur from perivascular extravasation, unintentional intra-arterial injection, and intraneuronal or perineuronal infiltration

            Deep IM injection is preferred method of administration

            Intra-arterial and SC administration are contraindicated

            25 mg/mL product may be administered by deep IM injection or IV infusion (at rate not to exceed 25 mg/min through flowing IV tubing)

            Monitor for signs and symptoms of potential tissue injury including burning or pain at site of injection, phlebitis, swelling, and blistering

            Discontinue IV infusion immediately if patient complains of pain during injection

            Respiratory fatalities reported with use in children <2 years (use contraindicated); use lowest effective dose in children >2 years; avoid other drugs with respiratory depressant effects

            Contraindications

            Hypersensitivity

            Newborn/premature infants <2 years old (risk of potentially fatal respiratory depression)

            SC or intra-arterial administration

            Coma

            Treatment of lower respiratory tract symptoms, including asthma

            Cautions

            Use caution in asthma, hepatic impairment, peptic ulcer disease, respiratory impairment, bone marrow suppression, anaphylaxis in susceptible individuals

            May impair ability to drive or perform hazardous tasks

            May impair core body temperature regulation; caution when taking medications with anticholinergic effects, heat exposure, or strenuous exercise

            Depresses hypothalamic thermoregulatory mechanism; exposure to extreme temperatures may cause hypo- or hyperthermia

            May alter cardiac conduction (life-threatening arrhythmias reported)

            Antiemetic effect may obscure toxicity of chemotherapeutic drugs

            Monitor closely in patients with cardiovascular disease, hepatic impairment, Reye syndrome, or history of sleep apnea

            Has anticholinergic effects; use with caution in patients with decreased gastrointestinal motility or obstructions (partial or complete), urinary retention, urinary obstructions, xerostomia, BPH, or visual problems

            May cause extrapyramidal symptoms including pseudoparkinsonism, acute dystonic reactions, tardive dyskinesia, and akathisia

            Neuroleptic malignant syndrome reported with use; monitor for fever, muscle rigidity and/or autonomic instability, or mental status changes

            May cause orthostatic hypotension; use caution in patients at risk of experiencing hypotensive episodes (cardiovascular disease, cerebrovascular disease, hypovolemia or taking medications that may predispose to bradycardia or hypotension)

            May cause photosensitivity

            Pyloroduodenal obstruction, stenosing peptic ulcer disease, bladder neck obstruction

            Anticholinergic effects of promethazine may exacerbate condition in patients with narrow-angle glaucoma or myasthenia gravis

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            Pregnancy & Lactation

            Pregnancy category: C

            Lactation: Not known whether drug crosses into breast milk; discontinue drug, or do not nurse

            Pregnancy Categories

            A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

            B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

            C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

            D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

            X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

            NA: Information not available.

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            Pharmacology

            Mechanism of Action

            Phenothiazine derivative with antidopaminergic effect: Blocker of mesolimbic dopamine receptors and alpha-adrenergic receptors in brain

            Antihistaminic effect: H1-receptor blocker

            Absorption

            Bioavailability: 25% (PO/PR)

            Onset (antihistaminic effect): 3-5 min (IV); 20 min (IM/PO/PR)

            Peak serum time: 6.7-8.6 hr (suppositories); 4.4 hr (syrup)

            Duration: PO (motion sickness), 4-6 hr; IV (nausea and vomiting), 4-6 hr; up to 12 hr

            Distribution

            Protein bound: 93%

            Vd: 98 L/kg (syrup); 17-277 L/kg (range)

            Metabolism

            Metabolized by hepatic P450 enzyme CYP2D6

            Metabolites: Promethazine sulfoxide and glucuronides (inactive)

            Elimination

            Dialyzable: No

            Half-life: 10 hr (IM); 9-16 hr (IV); 16-19 hr (syrup)

            Excretion: Urine (major), feces (minor)

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            Administration

            SC and intra-arterial injection contraindicated

            IV Compatibilities

            Solution: Compatible with most common solvents

            Additive: Amikacin, ascorbic acid injection, chloroquine, hydromorphone, netilmicin, vitamins B and C

            Syringe (partial list): Atropine, diphenhydramine, fentanyl, meperidine, morphine sulfate(?)

            Y-site (partial list): Ciprofloxacin, cisplatin, cladribine, cyclophosphamide, cytarabine, fluconazole, gemcitabine, linezolid, teniposide

            IV Incompatibilities

            Additive: Aminophylline, chloramphenicol, chlorothiazide, floxacillin, furosemide, heparin, hydrocortisone sodium succinate, methohexital, penicillin G potassium (incompatible at promethazine 250 mg/L and penicillin 20 million units/L; may be compatible at lower concentrations), penicillin G sodium, pentobarbital, phenobarbital, thiopental

            Syringe: Cefotetan, chloroquine, diatrizoate sodium 75%, diatrizoate meglumine/diatrizoate sodium, dimenhydrinate, heparin, iodipamide, iothalamate, ketorolac tromethamine, nalbuphine(?), pentobarbital, thiopental

            Y-site: Aldesleukin, allopurinol, amphotericin B cholesteryl sulfate, cefazolin(?), cefepime, cefoperazone, cefotetan, ceftizoxime(?), doxorubicin liposomal, foscarnet, heparin(?), hydrocortisone sodium succinate(?), methotrexate, piperacillin/tazobactam, potassium chloride(?), vitamins B and C(?)

            IV/IM Administration

            Administer by deep IM injection or by injection into tubing of running IV infusion solution

            IV: Concentration <25 mg/mL; infusion rate not to exceed 25 mg/min

            Avoid extravasation

            Storage

            Store at controlled room temperature; protect from freezing

            Protect from light

            Discard if particulate matter formation or discoloration occurs

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            Images

            BRAND FORM. UNIT PRICE PILL IMAGE
            promethazine rectal
            -
            25 mg suppos
            promethazine rectal
            -
            25 mg suppos
            promethazine rectal
            -
            12.5 mg suppos
            promethazine rectal
            -
            12.5 mg suppos
            promethazine rectal
            -
            25 mg suppos
            promethazine rectal
            -
            25 mg suppos
            promethazine rectal
            -
            25 mg suppos
            promethazine rectal
            -
            12.5 mg suppos
            promethazine injection
            -
            50 mg/mL vial
            promethazine injection
            -
            25 mg/mL solution
            promethazine injection
            -
            50 mg/mL solution
            promethazine injection
            -
            25 mg/mL vial
            promethazine injection
            -
            25 mg/mL vial
            promethazine injection
            -
            25 mg/mL solution
            promethazine injection
            -
            25 mg/mL solution
            promethazine injection
            -
            50 mg/mL solution
            promethazine injection
            -
            50 mg/mL solution
            promethazine injection
            -
            25 mg/mL solution
            promethazine injection
            -
            50 mg/mL solution
            promethazine injection
            -
            50 mg/mL solution
            promethazine injection
            -
            25 mg/mL solution
            promethazine oral
            -
            25 mg tablet
            promethazine oral
            -
            25 mg tablet
            promethazine oral
            -
            12.5 mg tablet
            promethazine oral
            -
            50 mg tablet
            promethazine oral
            -
            25 mg tablet
            promethazine oral
            -
            12.5 mg tablet
            promethazine oral
            -
            25 mg tablet
            promethazine oral
            -
            25 mg tablet
            promethazine oral
            -
            50 mg tablet
            promethazine oral
            -
            12.5 mg tablet
            promethazine oral
            -
            25 mg tablet
            promethazine oral
            -
            25 mg tablet
            promethazine oral
            -
            50 mg tablet
            promethazine oral
            -
            6.25 mg/5 mL syrup
            promethazine oral
            -
            6.25 mg/5 mL syrup
            promethazine oral
            -
            12.5 mg tablet
            promethazine oral
            -
            25 mg tablet
            promethazine oral
            -
            50 mg tablet
            promethazine oral
            -
            50 mg tablet
            promethazine oral
            -
            50 mg tablet
            Promethegan rectal
            -
            50 mg suppos
            Promethegan rectal
            -
            25 mg suppos
            Promethegan rectal
            -
            12.5 mg suppos
            Phenergan injection
            -
            25 mg/mL vial
            Phenergan injection
            -
            50 mg/mL vial
            Phenergan injection
            -
            25 mg/mL solution
            Phenergan injection
            -
            50 mg/mL solution
            Phenergan injection
            -
            25 mg/mL vial
            Phenadoz rectal
            -
            25 mg suppos
            Phenadoz rectal
            -
            12.5 mg suppos

            Copyright © 2010 First DataBank, Inc.

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            Patient Handout

            Select a drug:
            Patient Education
            promethazine rectal

            PROMETHAZINE SUPPOSITORY - RECTAL

            (proe-METH-a-zeen)

            COMMON BRAND NAME(S): Phenergan, Promethegan

            WARNING: Promethazine should not be used by children younger than 2 years because it may cause serious (possibly fatal) slow/shallow breathing. When this medication is used by children 2 years and older, the lowest effective dosage should be used, and other drugs that affect breathing should be avoided. Get medical help right away if slow/shallow breathing occurs.In children, drugs for nausea should only be used in cases of prolonged vomiting of a known cause. Avoid use of promethazine in children with liver disease (including possible Reye's syndrome).

            USES: See also Warning section.Promethazine is used to prevent and treat nausea and vomiting related to certain conditions (such as motion sickness, or before/after surgery). It is also used to treat allergy symptoms such as rash, itching, and runny nose. It may be used to help you feel sleepy/relaxed before and after surgery or to help certain opioid pain relievers (such as meperidine) work better. The suppository form is used when medications cannot be taken by mouth.Promethazine is an antihistamine and works by blocking a certain natural substance (histamine) that your body makes during an allergic reaction. Its other effects (such as anti-nausea, calming, pain relief) may work by affecting other natural substances (such as acetylcholine) and by acting directly on certain parts of the brain.

            HOW TO USE: Unwrap and insert one suppository rectally as directed by your doctor, usually 2 to 4 times daily. Remain lying down for a few minutes after using this medication, and avoid having a bowel movement for an hour or longer so the drug will be absorbed. The suppository is for rectal use only.For motion sickness, the first dose of promethazine should be used 30 to 60 minutes before beginning travel. For allergies, this medication may be used once daily at bedtime to avoid being drowsy during the day. When used before surgery, promethazine may be used the night before or just before the procedure and may be continued afterwards as directed.The dosage is based on your age, medical condition, and response to treatment. In children, the dosage may also be based on weight. Do not increase your dose or use this medication more often than directed.Tell your doctor if your condition does not improve or if it worsens.

            SIDE EFFECTS: Drowsiness, dizziness, constipation, blurred vision, or dry mouth may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.To relieve dry mouth, suck (sugarless) hard candy or ice chips, chew (sugarless) gum, drink water, or use a saliva substitute.Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.Tell your doctor right away if you have any serious side effects, including: fainting, slow heartbeat, mental/mood changes (such as hallucinations, nervousness, irritability, restlessness, confusion), unusual/uncontrolled movements (such as fixed upward stare, neck twisting, tongue movements), shaking (tremor), difficulty urinating, easy bleeding/bruising, signs of infection (such as fever, persistent sore throat), severe stomach/abdominal pain, persistent nausea/vomiting, yellowing eyes/skin.Get medical help right away if you have any very serious side effects, including: slow/shallow breathing, seizures.This medication may rarely cause a very serious condition called neuroleptic malignant syndrome (NMS). Get medical help right away if you have any of the following symptoms: fever, muscle stiffness/pain/tenderness/weakness, severe tiredness, severe confusion, sweating, fast/irregular heartbeat, dark urine, signs of kidney problems (such as change in the amount of urine).A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

            PRECAUTIONS: See also Warning section.Before using promethazine, tell your doctor or pharmacist if you are allergic to it; or to any other phenothiazines (such as prochlorperazine); or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.Before using this medication, tell your doctor or pharmacist your medical history, especially of: breathing problems (such as asthma, chronic obstructive pulmonary disease-COPD, sleep apnea), blood/immune system problems (such as bone marrow depression), high pressure in the eye (glaucoma), heart disease (such as irregular heartbeat), high blood pressure, liver disease, certain brain disorders (such as neuroleptic malignant syndrome, Reye's syndrome, seizures), stomach/intestine problems (such as blockage, ulcer), overactive thyroid (hyperthyroidism), difficulty urinating (for example, due to enlarged prostate).This drug may make you dizzy or drowsy or blur your vision. Alcohol or marijuana (cannabis) can make you more dizzy or drowsy. Do not drive, use machinery, or do anything that needs alertness or clear vision until you can do it safely. Avoid alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).This medication may make you more sensitive to the sun. Limit your time in the sun. Avoid tanning booths and sunlamps. Use sunscreen and wear protective clothing when outdoors. Tell your doctor right away if you get sunburned or have skin blisters/redness.This medication may make you sweat less, making you more likely to get heat stroke. Avoid doing things that may cause you to overheat, such as hard work or exercise in hot weather, or using hot tubs. When the weather is hot, drink a lot of fluids and dress lightly. If you overheat, quickly look for a place to cool down and rest. Get medical help right away if you have a fever that does not go away, mental/mood changes, headache, or dizziness.Children may be more sensitive to the side effects of this drug, especially slowed breathing and uncontrolled movements (see also Warning section). This drug can often cause excitement in young children instead of drowsiness. Special care should be taken when using this medication in children who have lost a lot of fluid (dehydration), those who have a family history of sudden infant death syndrome (SIDS), and those who are hard to wake up from sleep.Older adults may be more sensitive to the side effects of this drug, especially drowsiness, confusion, constipation, or trouble urinating. Drowsiness and confusion can increase the risk of falling.During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.It is unknown if promethazine passes into breast milk. It may have undesirable effects on a nursing infant. Consult your doctor before breast-feeding.

            DRUG INTERACTIONS: Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.Some products that may interact with this drug include: antihistamines applied to the skin (such as diphenhydramine cream, ointment, spray), metoclopramide.The risk of serious side effects (such as slow/shallow breathing, severe drowsiness/dizziness) may be increased if this medication is used with other products that may also cause drowsiness or breathing problems. Tell your doctor or pharmacist if you are taking other products such as opioid pain or cough relievers (such as codeine, hydrocodone), alcohol, marijuana (cannabis), drugs for sleep or anxiety (such as alprazolam, lorazepam, zolpidem), muscle relaxants (such as carisoprodol, cyclobenzaprine), or other antihistamines (such as cetirizine, diphenhydramine).Check the labels on all your medicines (such as allergy or cough-and-cold products) because they may contain ingredients that cause drowsiness. Ask your pharmacist about using those products safely.This medication may interfere with certain laboratory tests (including some pregnancy tests, glucose tolerance test, allergy skin testing), possibly causing false test results. Make sure laboratory personnel and all your doctors know you use this drug.

            OVERDOSE: This medicine may be harmful if swallowed. If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: severe drowsiness/dizziness, fainting, slow/shallow breathing, seizures, muscle stiffness/twitching, widened pupils. In children, mental/mood changes (such as restlessness, irritability, hallucinations) may occur before drowsiness.

            NOTES: Do not share this medication with others.

            MISSED DOSE: If you miss a dose, use it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Use your next dose at the regular time. Do not double the dose to catch up.

            STORAGE: Store in the refrigerator. Do not freeze. Keep all medications away from children and pets.Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.

            Information last revised June 2021. Copyright(c) 2021 First Databank, Inc.

            IMPORTANT: HOW TO USE THIS INFORMATION: This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.

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            Formulary

            FormularyPatient Discounts

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            Tier Description
            1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
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            5 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
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            NC NOT COVERED – Drugs that are not covered by the plan.
            Code Definition
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            Drugs that require prior authorization. This restriction requires that specific clinical criteria be met prior to the approval of the prescription.
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            Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.