Dosing & Uses
Dosage Forms & Strengths
oral liquid
- 12.5mg/5mL (Benadryl Allergy Childrens, PediaCare Children’s Allergy, Allergy Relief Childrens)
- 50mg/30mL (ZzzQuil)
elixir
- 12.5 mg/5mL (Altaryl)
syrup
- 12.5 mg/5mL (Altaryl, Quenalin, Silphen Cough)
tablet
- 25mg (Benadryl, Nytol, Simply Sleep, Sominex, Simply Allergy, Tetra-Formula Nighttime Sleep)
- 50mg (Aler-Dryl, Nytol Maximum Strength)
capsule
- 25mg (Benadryl Allergy Dye-Free Allergy, Anti-Hist Allergy, Allergy Relief, Diphenhist, Geri-Dryl)
- 50mg (Banophen, Pharbedryl)
tablet, chewable
- 12.5mg (Benadryl Allergy Childrens)
tablet, dispersible
- 25mg (Unisom SleepMelts)
strip
- 12.5mg (Triaminnic Cough/Runny Nose)
injectable solution
- 50mg/mL
Allergic Reaction
25-50 mg PO q6-8hr; not to exceed 300 mg/day
10-50 mg (no more than 100 mg) IV/IM q4-6hr; not to exceed 400 mg/day
Insomnia
50 mg PO 30 minutes before bedtime
Cough
25-50 mg PO q4hr PRN (syrup preferred); not to exceed 150 mg/day
Motion Sickness
Treatment or prophylaxis: 25-50 mg PO q6-8 hr
Alternatively, 10-50 mg/dose for treatment; may use up to 100 mg if needed; not to exceed 400 mg
Parkinsonism
25 mg PO q8hr initially, then 50 mg PO q6hr; not to exceed 300 mg/day
Alternatively, 10-50 mg IV at a rate not to exceed 25 mg/min; not to exceed 400 mg/day; may also administer 100 mg IM required
Dosage Forms & Strengths
oral solution
- 12.5mg/5mL (Benadryl Allergy Childrens, PediaCare Children’s Allergy, Allergy Relief Childrens)
- 50mg/30mL (ZzzQuil)
elixir
- 12.5 mg/5mL (Altaryl)
syrup
- 12.5 mg/5mL (Altaryl, Quenalin, Silphen Cough)
tablet
- 25mg (Benadryl, Nytol, Simply Sleep, Sominex, Simply Allergy, Tetra-Formula Nighttime Sleep)
- 50mg (Aler-Dryl, Nytol Maximum Strength)
capsule
- 25mg (Benadryl Allergy Dye-Free Allergy, Anti-Hist, Allergy Relief, Diphenhist, Geri-Dryl)
- 50mg (Banophen, Pharbedryl)
tablet, chewable
- 12.5mg (Benadryl Allergy Childrens)
tablet, dispersible
- 25mg (Unisom SleepMelts)
strip
- 12.5mg (Triaminnic Cough/Runny Nose)
injectable solution
- 50mg/mL
Allergic Reaction
2-6 years: 6.25 mg q4-6hr; not to exceed 37.5 mg/day
6-12 years: 12.5-25 mg PO q4-6hr; not to exceed 150 mg/day
>12 years: 25-50 mg PO q4-6hr; not to exceed 300 mg/day
Occasional Insomnia
< 12 years (off-label): 1 mg/kg; not to exceed 50 mg; 30 min before bedtime
>12 years: 50 mg PO 30 minutes before bedtime
Cough
<12 years: Safety and efficacy not established
>12 years: 25-50 mg PO q4-6hr; not to exceed 300 mg/day
Motion Sickness
Administer 30 min before motion
12.5-25 mg PO q6-8hr or 150 mg/m² ; not to exceed 300 mg/day
Allergic Reaction
25 mg PO/IV/IM q8-12hr; use only for emergency allergic reactions at smallest effective dose
Nonanticholinergic antihistamines should be considered first for treatment of allergic reaction (Beers criteria); use of diphenhydramine in acute treatment of severe allergic reaction may be appropriate
Dystonic Reaction
50 mg IV/IM; may be repeated in 20-30 minutes if necessary
Cough
25 mg PO q8-12hr; avoid in elderly if possible
Motion Sickness
25 mg PO/IV/IM q8-12hr
Dosing Modifications
Advanced age is associated with reduced clearance of drug and greater risk of confusion, dry mouth, constipation, and other anticholinergic effects and toxicity; if used, consider lower doses
In patients with parkinsonism who are unable to tolerate more potent agents, use at lowest effective dose
Interactions
Interaction Checker
No Results
Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor
Contraindicated (1)
- eliglustat
diphenhydramine increases levels of eliglustat by affecting hepatic enzyme CYP2D6 metabolism. Contraindicated. If coadministered with strong or moderate CYP2D6 inhibitors, reduce eliglustat dose from 84 mg BID to 84 mg once daily in extensive and intermediate metabolizers; eliglustat is contraindiated if strong or moderate CYP2D6 inhibitors are given concomitantly with strong or moderate CYP3A inhibitors.
Serious - Use Alternative (12)
- calcium/magnesium/potassium/sodium oxybates
diphenhydramine, 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.
- eluxadoline
diphenhydramine, 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.
- isocarboxazid
isocarboxazid increases effects of diphenhydramine 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. .
- mefloquine
mefloquine increases toxicity of diphenhydramine by QTc interval. Avoid or Use Alternate Drug. Mefloquine may enhance the QTc prolonging effect of high risk QTc prolonging agents.
- metoclopramide intranasal
diphenhydramine, 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.
- olopatadine intranasal
diphenhydramine 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.
- pitolisant
diphenhydramine 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.
- pramlintide
pramlintide, diphenhydramine. Either increases effects of the other by pharmacodynamic synergism. Contraindicated. Synergistic inhibition of GI motility.
- quinidine
quinidine, diphenhydramine. Mechanism: pharmacodynamic synergism. Contraindicated. Risk of prolonged QTc interval.
- sodium oxybate
diphenhydramine, sodium oxybate. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.
- thioridazine
diphenhydramine will increase the level or effect of thioridazine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.
- tranylcypromine
tranylcypromine increases effects of diphenhydramine 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. .
Monitor Closely (278)
- aclidinium
diphenhydramine and aclidinium both decrease cholinergic effects/transmission. Use Caution/Monitor.
- acrivastine
acrivastine and diphenhydramine both increase sedation. Use Caution/Monitor.
- albuterol
diphenhydramine increases and albuterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- alfentanil
diphenhydramine and alfentanil both increase sedation. Use Caution/Monitor.
- alprazolam
diphenhydramine and alprazolam both increase sedation. Use Caution/Monitor.
- amantadine
diphenhydramine, amantadine. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Potential for increased anticholinergic adverse effects.
- amifampridine
diphenhydramine 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 diphenhydramine both increase sedation. Use Caution/Monitor.
- amitriptyline
diphenhydramine and amitriptyline both decrease cholinergic effects/transmission. Modify Therapy/Monitor Closely.
diphenhydramine and amitriptyline both increase sedation. Use Caution/Monitor. - amobarbital
diphenhydramine and amobarbital both increase sedation. Use Caution/Monitor.
- amoxapine
diphenhydramine and amoxapine both decrease cholinergic effects/transmission. Use Caution/Monitor.
diphenhydramine and amoxapine both increase sedation. Use Caution/Monitor. - anticholinergic/sedative combos
anticholinergic/sedative combos and diphenhydramine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- apomorphine
diphenhydramine and apomorphine both increase sedation. Use Caution/Monitor.
- arformoterol
diphenhydramine increases and arformoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- aripiprazole
diphenhydramine and aripiprazole both increase sedation. Use Caution/Monitor.
diphenhydramine decreases levels of aripiprazole by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
diphenhydramine decreases levels of aripiprazole by pharmacodynamic antagonism. Use Caution/Monitor.
aripiprazole increases effects of diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia. - armodafinil
diphenhydramine increases and armodafinil decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- asenapine
asenapine and diphenhydramine both increase sedation. Use Caution/Monitor.
- asenapine transdermal
asenapine transdermal and diphenhydramine both increase sedation. Use Caution/Monitor.
- atomoxetine
diphenhydramine will increase the level or effect of atomoxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- atracurium
atracurium and diphenhydramine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- atropine
atropine and diphenhydramine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- atropine IV/IM
atropine IV/IM and diphenhydramine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- avapritinib
avapritinib and diphenhydramine both increase sedation. Use Caution/Monitor.
- azelastine
azelastine and diphenhydramine both increase sedation. Use Caution/Monitor.
- baclofen
diphenhydramine and baclofen both increase sedation. Use Caution/Monitor.
- belladonna alkaloids
belladonna alkaloids and diphenhydramine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- belladonna and opium
diphenhydramine and belladonna and opium both decrease cholinergic effects/transmission. Use Caution/Monitor.
diphenhydramine and belladonna and opium both increase sedation. Use Caution/Monitor. - benperidol
diphenhydramine and benperidol both increase sedation. Use Caution/Monitor.
diphenhydramine decreases levels of benperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
diphenhydramine decreases levels of benperidol by pharmacodynamic antagonism. Use Caution/Monitor.
benperidol increases effects of diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia. - benzhydrocodone/acetaminophen
diphenhydramine will increase the level or effect of benzhydrocodone/acetaminophen by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Hydromorphone (<3% of the circulating parent hydrocodone [benzhydrocodone is prodrug of hydrocodone]) is mainly formed by CYP2D6 mediated O-demethylation of hydrocodone. Hydromorphone may contribute to the total analgesic effect of hydrocodone.
benzhydrocodone/acetaminophen and diphenhydramine both increase sedation. Use Caution/Monitor. - benzphetamine
diphenhydramine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- benztropine
benztropine and diphenhydramine both decrease cholinergic effects/transmission. Use Caution/Monitor. Additive anticholinergic adverse effects may be seen with concurrent use.
- bethanechol
bethanechol increases and diphenhydramine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- brexanolone
brexanolone, diphenhydramine. Either increases toxicity of the other by sedation. Use Caution/Monitor.
- brexpiprazole
diphenhydramine will increase the level or effect of brexpiprazole by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Administer a quarter of brexpiprazole dose if coadministered with a moderate CYP2D6 inhibitor PLUS a strong/moderate CYP3A4 inhibitor.
brexpiprazole and diphenhydramine both increase sedation. Use Caution/Monitor. - brimonidine
brimonidine and diphenhydramine both increase sedation. Use Caution/Monitor.
- brivaracetam
brivaracetam and diphenhydramine both increase sedation. Use Caution/Monitor.
- brompheniramine
brompheniramine and diphenhydramine both increase sedation. Use Caution/Monitor.
- buprenorphine
diphenhydramine and buprenorphine both increase sedation. Use Caution/Monitor.
- buprenorphine buccal
diphenhydramine and buprenorphine buccal both increase sedation. Use Caution/Monitor.
- buprenorphine subdermal implant
buprenorphine subdermal implant and diphenhydramine both increase sedation. Use Caution/Monitor.
- buprenorphine transdermal
buprenorphine transdermal and diphenhydramine both increase sedation. Use Caution/Monitor.
- buprenorphine, long-acting injection
buprenorphine, long-acting injection and diphenhydramine both increase sedation. Use Caution/Monitor.
- butabarbital
diphenhydramine and butabarbital both increase sedation. Use Caution/Monitor.
- butalbital
diphenhydramine and butalbital both increase sedation. Use Caution/Monitor.
- butorphanol
diphenhydramine and butorphanol both increase sedation. Use Caution/Monitor.
- caffeine
diphenhydramine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- carbachol
carbachol increases and diphenhydramine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- carbinoxamine
carbinoxamine and diphenhydramine both increase sedation. Use Caution/Monitor.
- carisoprodol
diphenhydramine and carisoprodol both increase sedation. Use Caution/Monitor.
- carvedilol
diphenhydramine will increase the level or effect of carvedilol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- cenobamate
cenobamate, diphenhydramine. Either increases effects of the other by sedation. Use Caution/Monitor.
- cevimeline
cevimeline increases and diphenhydramine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- chloral hydrate
diphenhydramine and chloral hydrate both increase sedation. Use Caution/Monitor.
- chlordiazepoxide
diphenhydramine and chlordiazepoxide both increase sedation. Use Caution/Monitor.
- chlorpheniramine
chlorpheniramine and diphenhydramine both increase sedation. Use Caution/Monitor.
- chlorpromazine
diphenhydramine and chlorpromazine both increase sedation. Use Caution/Monitor.
diphenhydramine decreases levels of chlorpromazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
diphenhydramine decreases levels of chlorpromazine by pharmacodynamic antagonism. Use Caution/Monitor.
chlorpromazine increases effects of diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia. - chlorzoxazone
diphenhydramine and chlorzoxazone both increase sedation. Use Caution/Monitor.
- cinnarizine
cinnarizine and diphenhydramine both increase sedation. Use Caution/Monitor.
- cisatracurium
cisatracurium and diphenhydramine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- clemastine
clemastine and diphenhydramine both increase sedation. Use Caution/Monitor.
- clobazam
diphenhydramine, 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
diphenhydramine will increase the level or effect of clomipramine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
diphenhydramine and clomipramine both decrease cholinergic effects/transmission. Use Caution/Monitor.
diphenhydramine and clomipramine both increase sedation. Use Caution/Monitor. - clonazepam
diphenhydramine and clonazepam both increase sedation. Use Caution/Monitor.
- clorazepate
diphenhydramine and clorazepate both increase sedation. Use Caution/Monitor.
- clozapine
diphenhydramine and clozapine both increase sedation. Use Caution/Monitor.
diphenhydramine decreases levels of clozapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
diphenhydramine decreases levels of clozapine by pharmacodynamic antagonism. Use Caution/Monitor.
clozapine increases effects of diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia. - codeine
diphenhydramine decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.
diphenhydramine and codeine both increase sedation. Use Caution/Monitor. - cyclizine
cyclizine and diphenhydramine both decrease cholinergic effects/transmission. Use Caution/Monitor.
cyclizine and diphenhydramine both increase sedation. Use Caution/Monitor. - cyclobenzaprine
cyclobenzaprine and diphenhydramine both decrease cholinergic effects/transmission. Use Caution/Monitor.
diphenhydramine and cyclobenzaprine both increase sedation. Use Caution/Monitor. - cyproheptadine
cyproheptadine and diphenhydramine both increase sedation. Use Caution/Monitor.
- dantrolene
diphenhydramine and dantrolene both increase sedation. Use Caution/Monitor.
- daridorexant
diphenhydramine and daridorexant both increase sedation. Modify Therapy/Monitor Closely. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment.
- darifenacin
darifenacin and diphenhydramine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- desflurane
desflurane and diphenhydramine both increase sedation. Use Caution/Monitor.
- desipramine
diphenhydramine will increase the level or effect of desipramine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
diphenhydramine and desipramine both increase sedation. Use Caution/Monitor. - deutetrabenazine
diphenhydramine and deutetrabenazine both increase sedation. Use Caution/Monitor.
- dexchlorpheniramine
dexchlorpheniramine and diphenhydramine both increase sedation. Use Caution/Monitor.
- dexfenfluramine
diphenhydramine increases and dexfenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- dexmedetomidine
diphenhydramine and dexmedetomidine both increase sedation. Use Caution/Monitor.
- dexmethylphenidate
diphenhydramine increases and dexmethylphenidate decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- dextroamphetamine
diphenhydramine increases and dextroamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- dextromoramide
diphenhydramine and dextromoramide both increase sedation. Use Caution/Monitor.
- diamorphine
diphenhydramine and diamorphine both increase sedation. Use Caution/Monitor.
- diazepam
diphenhydramine and diazepam both increase sedation. Use Caution/Monitor.
- diazepam intranasal
diazepam intranasal, diphenhydramine. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration may potentiate the CNS-depressant effects of each drug.
- dicyclomine
dicyclomine and diphenhydramine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- diethylpropion
diphenhydramine increases and diethylpropion decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- difelikefalin
difelikefalin and diphenhydramine both increase sedation. Use Caution/Monitor.
- difenoxin hcl
diphenhydramine and difenoxin hcl both increase sedation. Use Caution/Monitor.
- dimenhydrinate
dimenhydrinate and diphenhydramine both increase sedation. Use Caution/Monitor.
- diphenoxylate hcl
diphenhydramine and diphenoxylate hcl both increase sedation. Use Caution/Monitor.
- dipipanone
diphenhydramine and dipipanone both increase sedation. Use Caution/Monitor.
- dobutamine
diphenhydramine increases and dobutamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- donepezil
donepezil increases and diphenhydramine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- donepezil transdermal
donepezil transdermal, diphenhydramine. Either decreases effects of the other by pharmacodynamic antagonism. Use Caution/Monitor.
- dopamine
diphenhydramine increases and dopamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- dopexamine
diphenhydramine increases and dopexamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- dosulepin
diphenhydramine and dosulepin both decrease cholinergic effects/transmission. Use Caution/Monitor.
diphenhydramine and dosulepin both increase sedation. Use Caution/Monitor. - doxepin
diphenhydramine and doxepin both decrease cholinergic effects/transmission. Use Caution/Monitor.
diphenhydramine and doxepin both increase sedation. Use Caution/Monitor. - doxylamine
diphenhydramine and doxylamine both increase sedation. Use Caution/Monitor.
- droperidol
diphenhydramine and droperidol both increase sedation. Use Caution/Monitor.
diphenhydramine decreases levels of droperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
diphenhydramine decreases levels of droperidol by pharmacodynamic antagonism. Use Caution/Monitor.
droperidol increases effects of diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia. - duloxetine
diphenhydramine will increase the level or effect of duloxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- echothiophate iodide
echothiophate iodide increases and diphenhydramine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- ephedrine
diphenhydramine increases and ephedrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- epinephrine
diphenhydramine increases and epinephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- epinephrine racemic
diphenhydramine increases and epinephrine racemic decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- esketamine intranasal
esketamine intranasal, diphenhydramine. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely.
- estazolam
diphenhydramine and estazolam both increase sedation. Use Caution/Monitor.
- ethanol
diphenhydramine and ethanol both increase sedation. Use Caution/Monitor.
- etomidate
etomidate and diphenhydramine both increase sedation. Use Caution/Monitor.
- fenfluramine
diphenhydramine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- fentanyl
fentanyl, diphenhydramine. 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, diphenhydramine. 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, diphenhydramine. 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, diphenhydramine. 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
diphenhydramine and fesoterodine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- flavoxate
diphenhydramine and flavoxate both decrease cholinergic effects/transmission. Use Caution/Monitor.
- flecainide
diphenhydramine will increase the level or effect of flecainide by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- flibanserin
diphenhydramine and flibanserin both increase sedation. Modify Therapy/Monitor Closely. Risk for sedation increased if flibanserin is coadministration with other CNS depressants.
- fluphenazine
diphenhydramine and fluphenazine both increase sedation. Use Caution/Monitor.
diphenhydramine decreases levels of fluphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
diphenhydramine decreases levels of fluphenazine by pharmacodynamic antagonism. Use Caution/Monitor.
fluphenazine increases effects of diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia. - flurazepam
diphenhydramine and flurazepam both increase sedation. Use Caution/Monitor.
- formoterol
diphenhydramine increases and formoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- gabapentin
gabapentin, diphenhydramine. 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, diphenhydramine. 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.
- galantamine
galantamine increases and diphenhydramine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- ganaxolone
diphenhydramine and ganaxolone both increase sedation. Use Caution/Monitor.
- glycopyrrolate
diphenhydramine and glycopyrrolate both decrease cholinergic effects/transmission. Use Caution/Monitor.
- glycopyrrolate inhaled
diphenhydramine and glycopyrrolate inhaled both decrease cholinergic effects/transmission. Use Caution/Monitor.
- glycopyrronium tosylate topical
glycopyrronium tosylate topical, diphenhydramine. 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 diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. May enhance CNS depression.
- haloperidol
diphenhydramine will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
diphenhydramine and haloperidol both increase sedation. Use Caution/Monitor.
diphenhydramine decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
diphenhydramine decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.
haloperidol increases effects of diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia. - hawthorn
hawthorn increases effects of diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. May enhance CNS depression.
- henbane
diphenhydramine and henbane both decrease cholinergic effects/transmission. Use Caution/Monitor.
- homatropine
diphenhydramine and homatropine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- hops
hops increases effects of diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. May enhance CNS depression.
- huperzine A
huperzine A increases and diphenhydramine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- hyaluronidase
diphenhydramine 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.
- hydrocodone
diphenhydramine will increase the level or effect of hydrocodone by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Hydromorphone (<3% of the circulating parent hydrocodone) is mainly formed by CYP2D6 mediated O-demethylation of hydrocodone. Hydromorphone may contribute to the total analgesic effect of hydrocodone.
- hydromorphone
diphenhydramine will increase the level or effect of hydromorphone by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
diphenhydramine and hydromorphone both increase sedation. Use Caution/Monitor. - hydroxyzine
diphenhydramine and hydroxyzine both increase sedation. Use Caution/Monitor.
- hyoscyamine
diphenhydramine and hyoscyamine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- hyoscyamine spray
diphenhydramine and hyoscyamine spray both decrease cholinergic effects/transmission. Use Caution/Monitor.
- iloperidone
diphenhydramine will increase the level or effect of iloperidone by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
diphenhydramine and iloperidone both increase sedation. Use Caution/Monitor.
diphenhydramine decreases levels of iloperidone by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
diphenhydramine decreases levels of iloperidone by pharmacodynamic antagonism. Use Caution/Monitor.
iloperidone increases effects of diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia. - imipramine
diphenhydramine will increase the level or effect of imipramine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
diphenhydramine and imipramine both decrease cholinergic effects/transmission. Use Caution/Monitor.
diphenhydramine and imipramine both increase sedation. Use Caution/Monitor. - ipratropium
diphenhydramine and ipratropium both decrease cholinergic effects/transmission. Use Caution/Monitor. Due to the poor systemic absorption of ipratropium, interaction unlikely at regularly recommended dosages.
- isoproterenol
diphenhydramine increases and isoproterenol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- kava
kava increases effects of diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. May enhance CNS depression.
- ketamine
ketamine and diphenhydramine both increase sedation. Use Caution/Monitor.
- ketotifen, ophthalmic
diphenhydramine and ketotifen, ophthalmic both increase sedation. Use Caution/Monitor.
- lasmiditan
lasmiditan, diphenhydramine. 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, diphenhydramine. 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
diphenhydramine increases and levalbuterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- levodopa
diphenhydramine, levodopa. Other (see comment). Use Caution/Monitor. Comment: Anticholinergic agents may enhance the therapeutic effects of levodopa; however, anticholinergic agents can exacerbate tardive dyskinesia. In high dosage, anticholinergics may decrease the effects of levodopa by delaying its GI absorption. .
- levorphanol
diphenhydramine and levorphanol both increase sedation. Use Caution/Monitor.
- lisdexamfetamine
diphenhydramine increases and lisdexamfetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- lofepramine
diphenhydramine will increase the level or effect of lofepramine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
diphenhydramine and lofepramine both decrease cholinergic effects/transmission. Use Caution/Monitor.
diphenhydramine and lofepramine both increase sedation. Use Caution/Monitor. - lofexidine
diphenhydramine and lofexidine both increase sedation. Use Caution/Monitor.
- loprazolam
diphenhydramine and loprazolam both increase sedation. Use Caution/Monitor.
- lorazepam
diphenhydramine and lorazepam both increase sedation. Use Caution/Monitor.
- lormetazepam
diphenhydramine and lormetazepam both increase sedation. Use Caution/Monitor.
- loxapine
diphenhydramine and loxapine both increase sedation. Use Caution/Monitor.
diphenhydramine decreases levels of loxapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
diphenhydramine decreases levels of loxapine by pharmacodynamic antagonism. Use Caution/Monitor.
loxapine increases effects of diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia. - loxapine inhaled
loxapine inhaled increases effects of diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.
diphenhydramine and loxapine inhaled both increase sedation. Use Caution/Monitor.
diphenhydramine decreases levels of loxapine inhaled by pharmacodynamic antagonism. Use Caution/Monitor. - lurasidone
lurasidone, diphenhydramine. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Potential for increased CNS depressant effects when used concurrently; monitor for increased adverse effects and toxicity.
- maprotiline
diphenhydramine and maprotiline both decrease cholinergic effects/transmission. Use Caution/Monitor.
diphenhydramine and maprotiline both increase sedation. Use Caution/Monitor. - marijuana
diphenhydramine and marijuana both increase sedation. Use Caution/Monitor.
- meclizine
diphenhydramine and meclizine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- melatonin
diphenhydramine and melatonin both increase sedation. Use Caution/Monitor.
- meperidine
diphenhydramine and meperidine both increase sedation. Use Caution/Monitor.
- meprobamate
diphenhydramine and meprobamate both increase sedation. Use Caution/Monitor.
- metaproterenol
diphenhydramine increases and metaproterenol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- metaxalone
diphenhydramine and metaxalone both increase sedation. Use Caution/Monitor.
- methadone
diphenhydramine and methadone both increase sedation. Use Caution/Monitor.
- methamphetamine
diphenhydramine will increase the level or effect of methamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
diphenhydramine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - methocarbamol
diphenhydramine and methocarbamol both increase sedation. Use Caution/Monitor.
- methscopolamine
diphenhydramine and methscopolamine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- methylenedioxymethamphetamine
diphenhydramine increases and methylenedioxymethamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- metoprolol
diphenhydramine will increase the level or effect of metoprolol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- mexiletine
diphenhydramine will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- midazolam
diphenhydramine and midazolam both increase sedation. Use Caution/Monitor.
- midazolam intranasal
midazolam intranasal, diphenhydramine. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Concomitant use of barbiturates, alcohol, or other CNS depressants may increase risk of hypoventilation, airway obstruction, desaturation, or apnea and may contribute to profound and/or prolonged drug effect.
- midodrine
diphenhydramine increases and midodrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- mirtazapine
diphenhydramine and mirtazapine both increase sedation. Use Caution/Monitor.
- modafinil
diphenhydramine increases and modafinil decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- morphine
diphenhydramine will increase the level or effect of morphine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
diphenhydramine and morphine both increase sedation. Use Caution/Monitor. - motherwort
diphenhydramine and motherwort both increase sedation. Use Caution/Monitor.
- moxonidine
diphenhydramine and moxonidine both increase sedation. Use Caution/Monitor.
- nabilone
diphenhydramine and nabilone both increase sedation. Use Caution/Monitor.
- nalbuphine
diphenhydramine and nalbuphine both increase sedation. Use Caution/Monitor.
- nebivolol
diphenhydramine will increase the level or effect of nebivolol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- neostigmine
neostigmine increases and diphenhydramine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- norepinephrine
diphenhydramine increases and norepinephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- nortriptyline
diphenhydramine will increase the level or effect of nortriptyline by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
diphenhydramine and nortriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.
diphenhydramine and nortriptyline both increase sedation. Use Caution/Monitor. - olanzapine
diphenhydramine and olanzapine both increase sedation. Use Caution/Monitor.
diphenhydramine decreases levels of olanzapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
diphenhydramine decreases levels of olanzapine by pharmacodynamic antagonism. Use Caution/Monitor.
olanzapine increases effects of diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia. - oliceridine
diphenhydramine will increase the level or effect of oliceridine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. If concomitant use is necessary, may require less frequent oliceridine dosing. Closely monitor for respiratory depression and sedation and titrate subsequent doses accordingly. If inhibitor is discontinued, consider increase oliceridine dosage until stable drug effects are achieved. Monitor for signs of opioid withdrawal.
- onabotulinumtoxinA
onabotulinumtoxinA and diphenhydramine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- opium tincture
diphenhydramine and opium tincture both increase sedation. Use Caution/Monitor.
- orphenadrine
diphenhydramine and orphenadrine both decrease cholinergic effects/transmission. Use Caution/Monitor.
diphenhydramine and orphenadrine both increase sedation. Use Caution/Monitor. - ospemifene
diphenhydramine, ospemifene. Either increases levels of the other by plasma protein binding competition. Modify Therapy/Monitor Closely.
- oxazepam
diphenhydramine and oxazepam both increase sedation. Use Caution/Monitor.
- oxybutynin
diphenhydramine and oxybutynin both decrease cholinergic effects/transmission. Use Caution/Monitor.
- oxybutynin topical
diphenhydramine and oxybutynin topical both decrease cholinergic effects/transmission. Use Caution/Monitor.
- oxybutynin transdermal
diphenhydramine and oxybutynin transdermal both decrease cholinergic effects/transmission. Use Caution/Monitor.
- oxycodone
diphenhydramine will increase the level or effect of oxycodone by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
diphenhydramine and oxycodone both increase sedation. Use Caution/Monitor. - oxymorphone
diphenhydramine will increase the level or effect of oxymorphone by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
diphenhydramine and oxymorphone both increase sedation. Use Caution/Monitor. - paliperidone
diphenhydramine and paliperidone both increase sedation. Use Caution/Monitor.
diphenhydramine decreases levels of paliperidone by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
diphenhydramine decreases levels of paliperidone by pharmacodynamic antagonism. Use Caution/Monitor.
paliperidone increases effects of diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia. - pancuronium
diphenhydramine and pancuronium both decrease cholinergic effects/transmission. Use Caution/Monitor.
- papaveretum
diphenhydramine and papaveretum both increase sedation. Use Caution/Monitor.
- papaverine
diphenhydramine and papaverine both increase sedation. Use Caution/Monitor.
- passion flower
passion flower increases effects of diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. May enhance CNS depression.
- pentazocine
diphenhydramine and pentazocine both increase sedation. Use Caution/Monitor.
- pentobarbital
diphenhydramine and pentobarbital both increase sedation. Use Caution/Monitor.
- perampanel
perampanel and diphenhydramine both increase sedation. Use Caution/Monitor.
- perphenazine
diphenhydramine and perphenazine both increase sedation. Use Caution/Monitor.
diphenhydramine decreases levels of perphenazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
diphenhydramine decreases levels of perphenazine by pharmacodynamic antagonism. Use Caution/Monitor.
perphenazine increases effects of diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia. - phendimetrazine
diphenhydramine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- phenelzine
phenelzine increases effects of diphenhydramine 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
diphenhydramine and phenobarbital both increase sedation. Use Caution/Monitor.
- phentermine
diphenhydramine increases and phentermine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- phenylephrine
diphenhydramine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- phenylephrine PO
diphenhydramine increases and phenylephrine PO decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. .
- pholcodine
diphenhydramine and pholcodine both increase sedation. Use Caution/Monitor.
- physostigmine
physostigmine increases and diphenhydramine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- pilocarpine
pilocarpine increases and diphenhydramine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- pimozide
diphenhydramine and pimozide both increase sedation. Use Caution/Monitor.
diphenhydramine decreases levels of pimozide by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
diphenhydramine decreases levels of pimozide by pharmacodynamic antagonism. Use Caution/Monitor.
pimozide increases effects of diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia. - pirbuterol
diphenhydramine increases and pirbuterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- pralidoxime
diphenhydramine and pralidoxime both decrease cholinergic effects/transmission. Use Caution/Monitor.
- pregabalin
pregabalin, diphenhydramine. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of CNS depressants can result in serious, life-threatening, and fatal respiratory depression. Use lowest dose possible and monitor for respiratory depression and sedation.
- primidone
diphenhydramine and primidone both increase sedation. Use Caution/Monitor.
- prochlorperazine
diphenhydramine and prochlorperazine both increase sedation. Use Caution/Monitor.
diphenhydramine decreases levels of prochlorperazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
diphenhydramine decreases levels of prochlorperazine by pharmacodynamic antagonism. Use Caution/Monitor.
prochlorperazine increases effects of diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia. - promethazine
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. - propafenone
diphenhydramine will increase the level or effect of propafenone by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- propantheline
diphenhydramine and propantheline both decrease cholinergic effects/transmission. Use Caution/Monitor.
- propofol
propofol and diphenhydramine both increase sedation. Use Caution/Monitor.
- propranolol
diphenhydramine will increase the level or effect of propranolol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- propylhexedrine
diphenhydramine increases and propylhexedrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- protriptyline
diphenhydramine and protriptyline both decrease cholinergic effects/transmission. Use Caution/Monitor.
diphenhydramine and protriptyline both increase sedation. Use Caution/Monitor. - pyridostigmine
pyridostigmine increases and diphenhydramine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- quazepam
diphenhydramine and quazepam both increase sedation. Use Caution/Monitor.
- quetiapine
diphenhydramine and quetiapine both increase sedation. Use Caution/Monitor.
diphenhydramine decreases levels of quetiapine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
diphenhydramine decreases levels of quetiapine by pharmacodynamic antagonism. Use Caution/Monitor.
quetiapine increases effects of diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia. - ramelteon
diphenhydramine and ramelteon both increase sedation. Use Caution/Monitor.
- rapacuronium
diphenhydramine and rapacuronium both decrease cholinergic effects/transmission. Use Caution/Monitor.
- risperidone
diphenhydramine and risperidone both increase sedation. Use Caution/Monitor.
diphenhydramine decreases levels of risperidone by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
diphenhydramine decreases levels of risperidone by pharmacodynamic antagonism. Use Caution/Monitor.
risperidone increases effects of diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia. - rocuronium
diphenhydramine and rocuronium both decrease cholinergic effects/transmission. Use Caution/Monitor.
- salmeterol
diphenhydramine increases and salmeterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- scopolamine
diphenhydramine and scopolamine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- scullcap
diphenhydramine and scullcap both increase sedation. Use Caution/Monitor.
- secobarbital
diphenhydramine and secobarbital both increase sedation. Use Caution/Monitor.
- sevoflurane
sevoflurane and diphenhydramine both increase sedation. Use Caution/Monitor.
- shepherd's purse
diphenhydramine and shepherd's purse both increase sedation. Use Caution/Monitor.
- solifenacin
diphenhydramine and solifenacin both decrease cholinergic effects/transmission. Use Caution/Monitor.
- stiripentol
stiripentol, diphenhydramine. Either increases effects of the other by sedation. Use Caution/Monitor. Concomitant use stiripentol with other CNS depressants, including alcohol, may increase the risk of sedation and somnolence.
- succinylcholine
succinylcholine increases and diphenhydramine decreases cholinergic effects/transmission. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- sufentanil
diphenhydramine and sufentanil both increase sedation. Use Caution/Monitor.
- tamoxifen
diphenhydramine decreases effects of tamoxifen by decreasing metabolism. Use Caution/Monitor. Inhibition of CYP2D6 metabolism to tamoxifen's active metabolite, endoxifen.
- tamsulosin
diphenhydramine increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- tapentadol
diphenhydramine and tapentadol both increase sedation. Use Caution/Monitor.
- temazepam
diphenhydramine and temazepam both increase sedation. Use Caution/Monitor.
- terbutaline
diphenhydramine increases and terbutaline decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- thioridazine
diphenhydramine and thioridazine both increase sedation. Use Caution/Monitor.
diphenhydramine decreases levels of thioridazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
diphenhydramine decreases levels of thioridazine by pharmacodynamic antagonism. Use Caution/Monitor.
thioridazine increases effects of diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia. - thiothixene
diphenhydramine and thiothixene both increase sedation. Use Caution/Monitor.
diphenhydramine decreases levels of thiothixene by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
diphenhydramine decreases levels of thiothixene by pharmacodynamic antagonism. Use Caution/Monitor.
thiothixene increases effects of diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia. - timolol
diphenhydramine will increase the level or effect of timolol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.
- tiotropium
diphenhydramine and tiotropium both decrease cholinergic effects/transmission. Use Caution/Monitor.
- tolterodine
diphenhydramine and tolterodine both decrease cholinergic effects/transmission. Use Caution/Monitor.
- topiramate
diphenhydramine and topiramate both increase sedation. Modify Therapy/Monitor Closely.
- tramadol
diphenhydramine decreases effects of tramadol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Decreased conversion of tramadol to active metabolite.
diphenhydramine and tramadol both increase sedation. Use Caution/Monitor.
diphenhydramine decreases effects of tramadol by decreasing metabolism. Use Caution/Monitor. Decreased conversion of tramadol to active metabolite. - trazodone
diphenhydramine and trazodone both increase sedation. Use Caution/Monitor.
- triazolam
diphenhydramine and triazolam both increase sedation. Use Caution/Monitor.
- triclofos
diphenhydramine and triclofos both increase sedation. Use Caution/Monitor.
- trifluoperazine
diphenhydramine and trifluoperazine both increase sedation. Use Caution/Monitor.
diphenhydramine decreases levels of trifluoperazine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
diphenhydramine decreases levels of trifluoperazine by pharmacodynamic antagonism. Use Caution/Monitor.
trifluoperazine increases effects of diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia. - trihexyphenidyl
diphenhydramine and trihexyphenidyl both decrease cholinergic effects/transmission. Use Caution/Monitor. Potential for additive anticholinergic effects.
- trimipramine
diphenhydramine and trimipramine both decrease cholinergic effects/transmission. Use Caution/Monitor.
diphenhydramine and trimipramine both increase sedation. Use Caution/Monitor. - triprolidine
diphenhydramine and triprolidine both increase sedation. Use Caution/Monitor.
- trospium chloride
diphenhydramine and trospium chloride both decrease cholinergic effects/transmission. Use Caution/Monitor.
- valerian
valerian increases effects of diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. May enhance CNS depression.
- vecuronium
diphenhydramine and vecuronium both decrease cholinergic effects/transmission. Use Caution/Monitor.
- xylometazoline
diphenhydramine increases and xylometazoline decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- yohimbine
diphenhydramine increases and yohimbine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- ziconotide
diphenhydramine and ziconotide both increase sedation. Use Caution/Monitor.
- ziprasidone
diphenhydramine and ziprasidone both increase sedation. Use Caution/Monitor.
diphenhydramine decreases levels of ziprasidone by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
diphenhydramine decreases levels of ziprasidone by pharmacodynamic antagonism. Use Caution/Monitor.
ziprasidone increases effects of diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia. - zotepine
diphenhydramine and zotepine both increase sedation. Use Caution/Monitor.
diphenhydramine decreases levels of zotepine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
diphenhydramine decreases levels of zotepine by pharmacodynamic antagonism. Use Caution/Monitor.
Minor (34)
- aripiprazole
diphenhydramine will increase the level or effect of aripiprazole by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.
- ashwagandha
ashwagandha increases effects of diphenhydramine by pharmacodynamic synergism. Minor/Significance Unknown. May enhance CNS depression.
- brimonidine
brimonidine increases effects of diphenhydramine by pharmacodynamic synergism. Minor/Significance Unknown. Increased CNS depression.
- chlorpromazine
diphenhydramine will increase the level or effect of chlorpromazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.
- desipramine
diphenhydramine and desipramine both decrease cholinergic effects/transmission. Minor/Significance Unknown.
desipramine and diphenhydramine both decrease cholinergic effects/transmission. Minor/Significance Unknown. - dexfenfluramine
diphenhydramine will increase the level or effect of dexfenfluramine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.
- dextroamphetamine
diphenhydramine will increase the level or effect of dextroamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.
- dextromethorphan
diphenhydramine will increase the level or effect of dextromethorphan by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.
- dimenhydrinate
dimenhydrinate increases toxicity of diphenhydramine by pharmacodynamic synergism. Minor/Significance Unknown. Additive anticholinergic effects.
- donepezil
diphenhydramine will increase the level or effect of donepezil by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.
donepezil decreases effects of diphenhydramine by pharmacodynamic antagonism. Minor/Significance Unknown. - doxepin
diphenhydramine will increase the level or effect of doxepin by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.
- encainide
diphenhydramine will increase the level or effect of encainide by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.
- eucalyptus
diphenhydramine and eucalyptus both increase sedation. Minor/Significance Unknown.
- fesoterodine
diphenhydramine will increase the level or effect of fesoterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.
- fluoxetine
diphenhydramine will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.
- fluphenazine
diphenhydramine will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.
- galantamine
diphenhydramine will increase the level or effect of galantamine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.
galantamine decreases effects of diphenhydramine by pharmacodynamic antagonism. Minor/Significance Unknown. - loratadine
diphenhydramine will increase the level or effect of loratadine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.
- nettle
nettle increases effects of diphenhydramine by pharmacodynamic synergism. Minor/Significance Unknown. (High dose nettle; theoretical interaction) May enhance CNS depression.
- nitazoxanide
nitazoxanide, diphenhydramine. Either increases levels of the other by Mechanism: plasma protein binding competition. Minor/Significance Unknown.
- oxycodone
diphenhydramine decreases effects of oxycodone by decreasing metabolism. Minor/Significance Unknown. Decreased conversion of oxycodone to active metabolite morphine.
- paroxetine
diphenhydramine will increase the level or effect of paroxetine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.
- perhexiline
diphenhydramine will increase the level or effect of perhexiline by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.
- perphenazine
diphenhydramine will increase the level or effect of perphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.
- prochlorperazine
diphenhydramine will increase the level or effect of prochlorperazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.
- promazine
diphenhydramine will increase the level or effect of promazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.
- promethazine
diphenhydramine will increase the level or effect of promethazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.
- risperidone
diphenhydramine will increase the level or effect of risperidone by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.
- sage
diphenhydramine and sage both increase sedation. Minor/Significance Unknown.
- Siberian ginseng
Siberian ginseng increases effects of diphenhydramine by pharmacodynamic synergism. Minor/Significance Unknown. May enhance CNS depression.
- tolterodine
diphenhydramine will increase the level or effect of tolterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.
- trazodone
diphenhydramine and trazodone both decrease cholinergic effects/transmission. Minor/Significance Unknown.
- trifluoperazine
diphenhydramine will increase the level or effect of trifluoperazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.
- tropisetron
diphenhydramine will increase the level or effect of tropisetron by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.
Adverse Effects
Frequency Not Defined
Sedation
Confusion
Anticholinergic effects
May decrease cognitive function in geriatric patients
Xerostomia
Dry nasal mucosa
Pharyngeal dryness
Thick bronchial sputum
Agranulocytosis
Hemolytic anemia
Thrombocytopenia
Convulsions
Tachycardia
Hypotension
Nervousness
Restlessness
Blurred vision
Palpitations
Constipation
Vertigo
Menstrual irregularities
Euphoria
Anorexia
Urinary retention
Neuritis
Diplopia
Tinnitus
Warnings
Contraindications
Documented hypersensitivity
Lower respiratory tract disease, such as acute asthma (controversial)
Premature infants or neonates
Nursing mothers
Use as local anesthetic
To make child <6 years sleep, when used for self-medication
Cautions
May cause CNS depression, which can impair driving or operating heavy machinery
May potentiate effects of sedatives such as alcohol
Use caution in patients with angle-closure glaucoma, prostatic hypertrophy, stenosing peptic ulcer, pyloroduodenal obstruction, thyroid dysfunction
Elderly patients: Considered high-risk medication for this age group because it may increase risk of falls and has high incidence of anticholinergic effects; may exacerbate existing lower urinary tract conditions or benign prostatic hyperplasia; use in special situations may be appropriate; not recommended for treatment of insomnia, because tolerance develops and risk of anticholinergic effects increases
Pregnancy & Lactation
Pregnancy category: B
Lactation: Drug enters breast milk; contraindicated
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
Histamine H1-receptor antagonist of effector cells in respiratory tract, blood vessels, and GI smooth muscle
Moderate to high anticholinergic and antiemetic properties
Absorption
Bioavailability: PO, 42-62% (drug is well absorbed but undergoes first-pass metabolism)
Onset: 15-30 min
Duration: ≤12 hr (histamine-induced flare suppression); ≤10 hr (histamine-induced wheal suppression)
Peak serum time: 2 hr (PO)
Distribution
Protein bound: 98.5%
Vd: 22 L/kg (Children); 17 L/kg (adults); 14 L/kg (elderly)
Metabolism
Metabolized by liver (first-pass)
Elimination
Half-life: 5 hr (children); 9 hr (adults); 13.5 hr (elderly)
Excretion: Urine (50-75%), mainly as metabolites
Administration
IV Incompatibilities
Additive: Amobarbital, amphotericin B, dexamethasone, sodium phosphate with lorazepam and metoclopramide, iodipamide meglumine, phenytoin, phenobarbital, thiopental
Syringe: Diatrizoate meglumine 52% and diatrizoate sodium 8%, diatrizoate sodium, haloperidol, iodipamide meglumine, ioxaglate meglumine 39.3% and ioxaglate sodium 19.6%, pentobarbital, thiopental
Y-site: Allopurinol, amphotericin B cholesteryl sulfate, cefepime, foscarnet, furosemide, phenytoin
IV Administration
pH: 5-6
Infuse at rate no higher than 25 mg/min
Check patency of IV and monitor for irritation
Storage
Store at room temperature of 15-30°C (59-86°F); protect from freezing and light
Images
| BRAND | FORM. | UNIT PRICE | PILL IMAGE |
|---|---|---|---|
| NightTime Sleep Aid (diphenhydramine) oral - | 25 mg tablet |  | |
| Children's Benadryl Allergy oral - | 12.5 mg chewable tablet |  | |
| Unisom SleepGels oral - | 50 mg capsule |  | |
| Unisom SleepGels oral - | 50 mg capsule |  | |
| Wal-Dryl Allergy oral - | 25 mg capsule |  | |
| Wal-Dryl Allergy oral - | 25 mg capsule |  | |
| Wal-Dryl Allergy oral - | 25 mg tablet |  | |
| Wal-Dryl Allergy oral - | 12.5 mg/5 mL liquid |  | |
| Wal-Dryl Allergy oral - | 12.5 mg/5 mL liquid |  | |
| Siladryl SA oral - | 12.5 mg/5 mL liquid |  | |
| Siladryl SA oral - | 12.5 mg/5 mL liquid |  | |
| Sominex oral - | 25 mg tablet |  | |
| Sleep II oral - | 25 mg tablet |  | |
| Geri-Dryl oral - | 25 mg tablet | | |
| Sleep Aid (diphenhydramine) oral - | 25 mg tablet | | |
| Sleep Aid (diphenhydramine) oral - | 50 mg capsule |  | |
| Simply Sleep oral - | 25 mg tablet |  | |
| Wal-Som (diphenhydramine) oral - | 50 mg capsule | | |
| Children's Allergy Relief (diphenhyd) oral - | 12.5 mg tablet |  | |
| Wal-Dryl (diphenhydramine) topical - | 2 % aerosol |  | |
| Allergy (diphenhydramine) oral - | 25 mg capsule |  | |
| Allergy (diphenhydramine) oral - | 25 mg capsule | | |
| Allergy (diphenhydramine) oral - | 25 mg tablet | | |
| Allergy (diphenhydramine) oral - | 25 mg tablet |  | |
| Allergy (diphenhydramine) oral - | 25 mg capsule | | |
| Children's Wal-Dryl Allergy oral - | 12.5 mg/5 mL liquid | | |
| Allergy Relief (diphenhydramine) oral - | 25 mg capsule | | |
| Allergy Relief (diphenhydramine) oral - | 25 mg tablet | | |
| Allergy Relief (diphenhydramine) oral - | 25 mg capsule |  | |
| Allergy Relief (diphenhydramine) oral - | 25 mg tablet | | |
| Allergy Relief (diphenhydramine) oral - | 25 mg chewable tablet |  | |
| Allergy Relief (diphenhydramine) oral - | 12.5 mg/5 mL liquid |  | |
| Allergy Relief (diphenhydramine) oral - | 25 mg tablet | | |
| Allergy Relief (diphenhydramine) oral - | 25 mg capsule |  | |
| ZzzQuil oral - | 25 mg capsule |  | |
| ZzzQuil oral - | 50 mg/30 mL liquid |  | |
| diphenhydramine oral - | 50 mg capsule |  | |
| diphenhydramine oral - | 25 mg capsule | | |
| diphenhydramine oral - | 50 mg capsule |  | |
| diphenhydramine oral - | 25 mg capsule |  | |
| diphenhydramine oral - | 50 mg capsule |  | |
| diphenhydramine oral - | 25 mg capsule |  | |
| diphenhydramine oral - | 25 mg tablet | | |
| Benadryl Allergy oral - | 25 mg tablet |  | |
| diphenhydramine injection - | 50 mg/mL vial |  | |
| diphenhydramine injection - | 50 mg/mL vial |  | |
| diphenhydramine injection - | 50 mg/mL solution |  | |
| diphenhydramine injection - | 50 mg/mL solution |  | |
| diphenhydramine injection - | 50 mg/mL vial |  | |
| diphenhydramine injection - | 50 mg/mL vial |  | |
| diphenhydramine injection - | 50 mg/mL vial |  | |
| diphenhydramine injection - | 50 mg/mL vial |  | |
| diphenhydramine injection - | 50 mg/mL vial |  | |
| Benadryl topical - | 2 % gel |  | |
| Children's Allergy (diphenhydramine) oral - | 12.5 mg/5 mL liquid |  | |
| Children's Allergy (diphenhydramine) oral - | 12.5 mg/5 mL liquid |  | |
| Children's Allergy (diphenhydramine) oral - | 12.5 mg/5 mL liquid |  | |
| Children's Allergy (diphenhydramine) oral - | 12.5 mg/5 mL liquid |  | |
| Benadryl oral - | 25 mg capsule |  | |
| Banophen oral - | 25 mg capsule | | |
| Banophen oral - | 25 mg capsule | | |
| Banophen oral - | 25 mg tablet | | |
| Banophen oral - | 50 mg capsule | |
Copyright © 2010 First DataBank, Inc.
Patient Handout
diphenhydramine injection
DIPHENHYDRAMINE - INJECTION
(dye-fen-HI-druh-meen)
COMMON BRAND NAME(S): Benadryl
USES: Diphenhydramine injection is an antihistamine used to treat life-threatening allergic reactions (anaphylaxis) along with epinephrine and other treatments. It is also used to relieve symptoms of household allergies, hay fever and the common cold when medication cannot be given by mouth. Common allergy symptoms relieved by antihistamines include rash, itching, watery eyes, itchy eyes/nose/throat, cough, runny nose and sneezing.It is also used to treat nausea, vomiting and dizziness caused by motion sickness when medication cannot be given by mouth. Diphenhydramine works by blocking a certain natural substance (histamine) that your body makes during an allergic reaction. Its drying effects on such symptoms as watery eyes and runny nose are caused by blocking another natural substance made by your body (acetylcholine).Diphenhydramine should not be used in newborns or premature infants because of an increased risk of side effects. It should not be used for common cold symptoms in children less than 6 years of age due to the risk of serious side effects, such as slow/shallow breathing. Cough-and-cold products have not been shown to be safe or effective in children younger than 6.
HOW TO USE: This medication is injected into a vein or into a muscle as directed by your doctor. Be very careful to inject into a vein or muscle and not into the skin or just under the skin. If this medication is injected into or just under the skin, it can destroy the skin and tissues around the injection site (necrosis).If you are giving this medication to yourself 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.Do not use this medication more often than prescribed. The dosage is based on your medical condition and response to treatment. Tell your doctor if your condition does not improve or if it worsens.
SIDE EFFECTS: Drowsiness, dizziness, headache, irritability, stomach upset, blurred vision, decreased coordination, constipation, or dry mouth/nose/throat may occur. These effects may decrease as your body adjusts to the medication. If any of these effects last or get worse, tell your doctor or pharmacist promptly.To relieve dry mouth, suck on (sugarless) hard candy or ice chips, chew (sugarless) gum, drink water or use a saliva substitute.To reduce the risk of dizziness and lightheadedness, get up slowly when rising from a sitting or lying position.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: mental/mood changes (such as restlessness, confusion), pounding/irregular heartbeat, ringing in the ears, seizure, difficulty urinating.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: Before using diphenhydramine, tell your doctor or pharmacist if you are allergic to it; or to dimenhydrinate; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.Before using this medication, tell your doctor or pharmacist your medical history, especially of: breathing problems (such as asthma, emphysema), glaucoma, heart problems, high blood pressure, liver disease, mental/mood disorders, seizures, stomach problems (such as ulcers, obstruction), overactive thyroid, difficulty urinating (such as due to enlarged prostate, urinary retention).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. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).Children may be more sensitive to the side effects of this drug. This drug can often cause excitement in young children instead of drowsiness.Older adults may be more sensitive to the side effects of this drug, especially drowsiness, dizziness, low blood pressure, confusion, constipation, or trouble urinating. Drowsiness, dizziness, and confusion can increase the risk of falling.During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.This drug passes into breast milk and 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).Tell your doctor or pharmacist if you are taking other products that cause drowsiness 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, chlorpheniramine).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 allergy skin test), 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, seizures, widened pupils. In children, mental/mood changes (such as restlessness, irritability, hallucinations) may occur before drowsiness.
NOTES: Do not share this medication with others.
MISSED DOSE: If you miss a dose, use it as soon you remember. If it is near the time of your 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. 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 August 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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