Dosing & Uses
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
Interactions
Interaction Checker
No Results

Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor

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 (84)
- amiodarone
promethazine and amiodarone both increase QTc interval. Avoid or Use Alternate Drug.
- amisulpride
promethazine and amisulpride both increase QTc interval. Avoid or Use Alternate Drug. ECG monitoring is recommended if coadministered.
- anagrelide
anagrelide and promethazine both decrease 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.
- asenapine
asenapine and promethazine both decrease QTc interval. Avoid or Use Alternate Drug.
- asenapine transdermal
asenapine transdermal and promethazine both decrease QTc interval. Avoid or Use Alternate Drug.
- benzhydrocodone/acetaminophen
benzhydrocodone/acetaminophen and promethazine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate
- bromocriptine
promethazine decreases effects of bromocriptine by pharmacodynamic antagonism. Avoid or Use Alternate Drug.
- buprenorphine
buprenorphine and promethazine both decrease QTc interval. Avoid or Use Alternate Drug.
- buprenorphine buccal
buprenorphine buccal and promethazine both decrease QTc interval. Avoid or Use Alternate Drug.
- buprenorphine subdermal implant
buprenorphine subdermal implant and promethazine both decrease QTc interval. Avoid or Use Alternate Drug.
buprenorphine subdermal implant and promethazine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate - buprenorphine transdermal
buprenorphine transdermal and promethazine both decrease QTc interval. Avoid or Use Alternate Drug.
buprenorphine transdermal and promethazine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate - buprenorphine, long-acting injection
buprenorphine, long-acting injection and promethazine both decrease QTc interval. Avoid or Use Alternate Drug.
buprenorphine, long-acting injection and promethazine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate - 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.
- degarelix
degarelix and promethazine both decrease QTc interval. Avoid or Use Alternate Drug.
- 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.
- eliglustat
eliglustat and promethazine both decrease 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.
- encorafenib
encorafenib and promethazine both decrease QTc interval. Avoid or Use Alternate Drug.
- entrectinib
entrectinib and promethazine both decrease QTc interval. Avoid or Use Alternate Drug.
- 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.
- eribulin
eribulin and promethazine both decrease 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.
- fingolimod
fingolimod and promethazine both decrease QTc interval. Avoid or Use Alternate Drug.
- 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.
- levoketoconazole
promethazine and levoketoconazole both increase QTc interval. 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.
- olopatadine intranasal
promethazine and olopatadine intranasal both increase sedation. Avoid or Use Alternate Drug. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment.
- oxaliplatin
oxaliplatin and promethazine both decrease 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.
- siponimod
siponimod and promethazine both decrease QTc interval. Avoid or Use Alternate Drug.
- 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.
- tetrabenazine
tetrabenazine and promethazine both decrease QTc interval. Avoid or Use Alternate Drug.
- 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 (317)
- 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. - acrivastine
acrivastine and promethazine both increase sedation. Use Caution/Monitor.
- 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.
- amisulpride
amisulpride and promethazine both increase sedation. Use Caution/Monitor.
- 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).
asenapine and promethazine both increase sedation. Use Caution/Monitor. - asenapine transdermal
asenapine transdermal and promethazine both increase sedation. Use Caution/Monitor.
- 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.
- avapritinib
avapritinib and promethazine both increase sedation. Use Caution/Monitor.
- 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.
- brexpiprazole
brexpiprazole and promethazine both increase sedation. Use Caution/Monitor.
- brimonidine
brimonidine and promethazine both increase sedation. Use Caution/Monitor.
- brivaracetam
brivaracetam and promethazine both increase 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.
- daridorexant
promethazine and daridorexant both increase sedation. Modify Therapy/Monitor Closely. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment.
- darifenacin
darifenacin decreases 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.
desflurane and promethazine both decrease QTc interval. 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.
deutetrabenazine and promethazine both decrease QTc interval. Use Caution/Monitor. At the maximum recommended dose, deutetrabenazine does not prolong QT interval to a clinically relevant extent. Certain circumstances may increase risk of torsade de pointes and/or sudden death in association with drugs that prolong the QTc interval (eg, bradycardia, hypokalemia or hypomagnesemia, coadministration with other drugs that prolong QTc interval, presence of congenital QT prolongation). - 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. - difelikefalin
difelikefalin and promethazine both increase sedation. Use Caution/Monitor.
- 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.
- donepezil
donepezil and promethazine both decrease QTc interval. Use Caution/Monitor.
- donepezil transdermal
donepezil transdermal, promethazine. Either decreases effects of the other by pharmacodynamic antagonism. Use Caution/Monitor.
- 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. - efavirenz
efavirenz and promethazine both decrease QTc interval. 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.
- ganaxolone
promethazine and ganaxolone both increase sedation. Use Caution/Monitor.
- gemifloxacin
gemifloxacin and promethazine both decrease QTc interval. Use Caution/Monitor.
- gilteritinib
gilteritinib and promethazine both decrease QTc interval. Use Caution/Monitor.
- 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.
- granisetron
granisetron and promethazine both decrease QTc interval. Use Caution/Monitor.
- 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.
hydroxyzine and promethazine both decrease QTc interval. 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. - isoflurane
isoflurane and promethazine both decrease QTc interval. Use Caution/Monitor.
- 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.
lithium and promethazine both decrease QTc interval. Use Caution/Monitor. - 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.
mirtazapine and promethazine both decrease QTc interval. 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).
olanzapine and promethazine both decrease QTc interval. Use Caution/Monitor. - 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.
- primaquine
primaquine and promethazine both decrease QTc interval. Use Caution/Monitor.
- 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.
- serdexmethylphenidate/dexmethylphenidate
promethazine, serdexmethylphenidate/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.
- sertraline
sertraline and promethazine both decrease QTc interval. Use Caution/Monitor.
- sevoflurane
sevoflurane and promethazine both increase sedation. Use Caution/Monitor.
sevoflurane and promethazine both decrease QTc interval. 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.
solifenacin and promethazine both decrease QTc interval. Use Caution/Monitor. - sparsentan
sparsentan will decrease the level or effect of promethazine by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor. Sparsentan (a CYP2B6 inducer) decreases exposure of CYP2B6 substrates and reduces efficacy related to these substrates.
- 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.
- sunitinib
sunitinib and promethazine both decrease QTc interval. Use Caution/Monitor.
- tacrolimus
tacrolimus and promethazine both decrease QTc interval. Use Caution/Monitor.
- 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. - valbenazine
valbenazine and promethazine both decrease QTc interval. Use Caution/Monitor.
- 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.
- vorinostat
vorinostat and promethazine both decrease QTc interval. Use Caution/Monitor.
- 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.
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
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
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.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)
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
Images
BRAND | FORM. | UNIT PRICE | PILL IMAGE |
---|---|---|---|
Phenergan injection - | 25 mg/mL vial | ![]() | |
Phenergan injection - | 50 mg/mL vial | ![]() | |
Phenergan injection - | 25 mg/mL vial | ![]() | |
Phenergan injection - | 50 mg/mL solution | ![]() | |
Phenergan injection - | 25 mg/mL solution | ![]() | |
promethazine injection - | 25 mg/mL solution | ![]() | |
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 - | 50 mg/mL solution | ![]() | |
promethazine injection - | 25 mg/mL solution | ![]() | |
promethazine injection - | 25 mg/mL solution | ![]() | |
promethazine injection - | 25 mg/mL vial | ![]() | |
promethazine injection - | 50 mg/mL vial | ![]() | |
promethazine injection - | 25 mg/mL vial | ![]() | |
promethazine injection - | 50 mg/mL solution | ![]() | |
promethazine injection - | 25 mg/mL solution | ![]() | |
promethazine injection - | 50 mg/mL solution | ![]() | |
promethazine injection - | 50 mg/mL vial | ![]() | |
promethazine injection - | 25 mg/mL vial | ![]() | |
promethazine rectal - | 12.5 mg suppos | ![]() | |
promethazine rectal - | 25 mg suppos | ![]() | |
promethazine rectal - | 25 mg suppos | ![]() | |
promethazine rectal - | 12.5 mg suppos | ![]() | |
promethazine rectal - | 25 mg suppos | ![]() | |
promethazine rectal - | 25 mg suppos | ![]() | |
promethazine rectal - | 12.5 mg suppos | ![]() | |
promethazine rectal - | 25 mg suppos | ![]() | |
Promethegan rectal - | 50 mg suppos | ![]() | |
Promethegan rectal - | 12.5 mg suppos | ![]() | |
Promethegan rectal - | 25 mg suppos | ![]() | |
promethazine oral - | 25 mg tablet | ![]() | |
promethazine oral - | 12.5 mg tablet | ![]() | |
promethazine oral - | 12.5 mg tablet | ![]() | |
promethazine oral - | 25 mg tablet | ![]() | |
promethazine oral - | 12.5 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 - | 25 mg tablet | ![]() | |
promethazine oral - | 50 mg tablet | ![]() | |
promethazine oral - | 25 mg tablet | ![]() | |
promethazine oral - | 25 mg tablet | ![]() | |
promethazine oral - | 50 mg tablet | ![]() | |
promethazine oral - | 50 mg tablet | ![]() | |
promethazine oral - | 6.25 mg/5 mL syrup | ![]() | |
promethazine oral - | 50 mg tablet | ![]() | |
promethazine oral - | 6.25 mg/5 mL syrup | ![]() | |
promethazine oral - | 50 mg tablet | ![]() | |
promethazine oral - | 50 mg tablet | ![]() |
Copyright © 2010 First DataBank, Inc.
Patient Handout
promethazine injection
PROMETHAZINE - INJECTION
(pro-METH-uh-zeen)
COMMON BRAND NAME(S): Phenergan
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, use the lowest effective dosage and avoid other drugs that affect breathing. 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).This medication can cause severe tissue damage, possibly requiring surgery. Tell your health care professional right away if you have burning, pain, redness, swelling, or numbness at or near the injection site. If this occurs, the injection should be stopped and the injection site checked.It is preferred that this medication be given by injection into a muscle. There may be an increased risk of side effects if this medication is given by injection into a vein. This medication must not be given by injection under the skin.
USES: Promethazine is used to prevent and treat nausea and vomiting related to certain conditions (such as before/after surgery, motion sickness). It is also used with other medication to treat severe allergic reactions (anaphylaxis) and reactions to blood products. It may also be used to treat milder allergic reactions when you cannot take promethazine by mouth. It may also be used to help you feel sleepy/relaxed before and after surgery, during other procedures, or during labor and delivery. It may also be used to help certain opioid pain relievers (such as meperidine) work better.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.This drug is not approved for use in children younger than 2 years due to an increased risk of side effects (such as slow/shallow breathing). See also Warning section.
HOW TO USE: See also Warning section.It is best to inject this medication deep into a muscle. It may also be given by injection slowly into a large vein by a health care professional. Do not inject this medication under the skin or into an artery. For nausea and vomiting, use this medication as directed by your doctor, usually every 4 hours as needed. If you have any questions about the proper use of this medication, ask your doctor or pharmacist.If you are using this medication at home, learn all preparation and usage instructions from your health care professional. Before using, check this product visually for particles or discoloration. If either is present, do not use the liquid. Learn how to store and discard medical supplies safely.The dosage and how often you receive this medication are 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 or for longer than prescribed. Your condition will not improve any faster, and your risk of side effects will increase.Tell your doctor if you do not get better or if you get worse.
SIDE EFFECTS: See also Warning section.Drowsiness, dizziness, constipation, blurred vision, or dry mouth may occur. If any of these effects last or get worse, 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 this medication has been prescribed because your doctor 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: signs of infection (such as sore throat that doesn't go away, fever, chills), loss of coordination, fainting, confusion, slow heartbeat, shaking (tremor), unusual/uncontrolled movements (such as fixed upward stare, neck twisting, tongue movements), mental/mood changes (such as hallucinations, nervousness, irritability, restlessness, confusion), trouble urinating, easy bleeding/bruising, severe stomach/abdominal pain, yellowing of 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 (such as sulfites including sodium metabisulfite), 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 angina, irregular heartbeat), high or low blood pressure, liver disease, certain brain disorders (such as neuroleptic malignant syndrome, Reye's syndrome, seizures), stomach/intestinal problems (such as blockage, ulcer), trouble 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). Children should be supervised during bicycle riding and other possibly hazardous activities to avoid injury.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.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.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.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 lab tests (such as some pregnancy tests, blood sugar tests), possibly causing false test results. Make sure lab personnel and all your doctors know you use this drug.
OVERDOSE: 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 are using this medication on a regular schedule and 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 at room temperature away from light and moisture. Do not store in the bathroom. 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 July 2023. Copyright(c) 2023 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.
Formulary
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Adding plans allows you to:
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