Brexpiprazole
Severe
Database
Drug interaction classified as: metabolism
Source: DDInter
Drug reference
diphenhydramine
antihistamines · Antihistamine
antihistaminesAntihistamine
CDSCO approved
EXCRETION
—
not curated
INTERACTIONS
12 major
SEVERE in our sources
PREGNANCY
B
FDA category + note
Top interactionssee all 12 →
- BrexpiprazoleSevereDatabaseDDInter
- DextropropoxypheneSevereDatabaseDDInter
- EliglustatSevereDatabaseDDInter
- HydroxyzineSevereDatabaseDDInter
Mechanism
Diphenhydramine is actively taken up at the blood-brain barrier. It has the highest active brain uptake of all drugs measured thus far, leading to its pronounced sedative effects.
Indications
Acute dystonia prophylaxissedationTreatment of PDOver-the-counter nonprescription sleep aidsmotion sickness (prophylactic, milder types)acute muscle dystonia (caused by antidopaminergic-antipsychotic drugs)idiopathic pruritusCough in respiratory allergic statesmotion sicknesspruritus control in Atopic Dermatitisimprove sleep in AD patients due to sedation
Dosing
- Adult
- Parenteral: 25–50 mg IM (for acute dystonia prophylaxis and sedation).
Pharmacokinetics
Half-life
about 9 to 10 h
Bioavailability
5 (Kp,uu,brain)
Side effects
Common
sedationcognitive impairmentperipheral antimuscarinic adverse effectsmental confusionanticholinergic propertiesProminent residual sleepiness the morning afterdiminished alertnesslight headednessmotor incoordinationfatiguetendency to fall asleepdry mouthalteration of bowel movementurinary hesitancyblurring of visionAnticholinergic actions (may reduce secretions)dryness of mouthsedation (can become bothersome)
Serious
- Exacerbation of tardive dyskinesia
- cholinergic rebound following abrupt anticholinergic withdrawal
Pregnancy & lactation
Pregnancy
B
Lactation
Not specified
Drug interactions
Dextropropoxyphene
Severe
Database
Clinical effect not specified
Source: DDInter
Eliglustat
Severe
Database
Clinical effect not specified
Source: DDInter
Hydroxyzine
Severe
Database
Increased sedation, dizziness, dry mouth, urinary retention, constipation, blurred vision, cognitive impairment.
Avoid concomitant use of multiple antihistamines with significant anticholinergic and sedative properties. Choose one agent.
Source: DDInter
Levacetylmethadol
Severe
Database
Clinical effect not specified
Source: DDInter
Potassium Chloride
Severe
Database
.
Source: DDInter
Potassium Citrate
Severe
Database
Clinical effect not specified
Source: DDInter
Sodium Oxybate
Severe
Database
.
Source: DDInter
Tamoxifen
Severe
Database
.
Source: DDInter
Thioridazine
Severe
Database
Clinical effect not specified
Source: DDInter
Topiramate
Severe
Database
.
Source: DDInter
Zonisamide
Severe
Database
Clinical effect not specified
Source: DDInter
Related guidelines
Childhood pneumonia and respiratory infection
MOHFW · Paediatrics · 2021
Venous thromboembolism prophylaxis
ASH · Haematology · 2018
Infective endocarditis prevention
NICE · Cardiology / Dentistry · 2008
Infective endocarditis prevention
AHA · Cardiology / Dentistry · 2007
Drug-resistant tuberculosis
RNTCP · Pulmonology · 2025
Ask House about diphenhydramine
Continue into a citation-backed clinical answer with the drug context already attached.
Sources: KD Tripathi 7e, Goodman & Gilman 14e, Harrison 22e·Verified: 2026-05-10 · House clinical team