Section 11 · Monograph
Dimenhydrinate
Reviewed Nov 2026FDA label
DramamineH1 antihistamine
- Forms
- Tab: 50mg | Chew: 50mg
- Dose
- 50-100mg q4-6h (max 400mg/day)
- MOA
- H1/muscarinic blockade, antiemetic
Indications
- Prevention and treatment of nausea, vomiting or dizziness of motion sicknessFDA-labeled
Off-Label Uses
- Short-term symptomatic treatment of acute vestibular vertigoOff-label
Mechanism of Action
- H1 antihistamine (diphenhydramine salt) with anticholinergic activity that suppresses vestibular signaling and emesis
Full Dosing
Adult / usual
- 50-100mg every 4-6 hours; maximum 400mg/day in adults
- Motion sickness: take 30 minutes before travel
Contraindications
- Hypersensitivity
- Use with caution in narrow-angle glaucoma, urinary retention and prostatic hypertrophy
Drug Interactions
- Additive sedation with alcohol and CNS depressants
- Additive anticholinergic effects
Adverse Effects
- Drowsiness, dry mouth, blurred vision
- Urinary retention
- Confusion in older adults
Monitoring Parameters
- Sedation and fall risk
- Anticholinergic burden
Pregnancy & Lactation
- Generally considered acceptable for short-term use in pregnancy
- Small amounts in milk; may cause infant drowsiness