Gravol (Dimenhydrinate) Oral Dosing
For adults and children ≥12 years: 50-100 mg every 4-6 hours (maximum 400 mg/24 hours); for children 6 to <12 years: 50 mg every 6-8 hours (maximum 150 mg/24 hours). 1
Adult Dosing
- Standard dose: 50-100 mg (1-2 capsules of 50 mg) every 4-6 hours
- Maximum daily dose: 400 mg (8 capsules) in 24 hours
- For motion sickness prevention: Take first dose 30-60 minutes before travel 1
Pediatric Dosing
Children 6 to <12 years:
- Dose: 50 mg (1 capsule) every 6-8 hours
- Maximum daily dose: 150 mg (3 capsules) in 24 hours 1
Children 1-6 years:
- The FDA-labeled product 1 does not provide dosing for children under 6 years for the 50 mg capsule formulation
- Research studies have used 1 mg/kg every 6 hours (maximum 50 mg per dose) in children as young as 1 year 2, 3
Active Ingredient
Each capsule contains dimenhydrinate 50 mg 1
Clinical Context
Evidence for Nausea/Vomiting in Gastroenteritis
While dimenhydrinate is commonly used as an antiemetic, high-quality evidence shows it is NOT effective for reducing vomiting in children with acute gastroenteritis 3. A randomized controlled trial of 144 children found no difference in treatment failure rates between dimenhydrinate (1 mg/kg every 6 hours) and placebo (31% vs 29%). The IDSA guidelines 4 note that dimenhydrinate has been beneficial in adults for facilitating oral rehydration, but ondansetron is the preferred antiemetic for children >4 years with gastroenteritis-associated vomiting.
Important Caveats
- Sedation is common: Drowsiness occurs in up to 78% of patients taking dimenhydrinate 5
- Anticholinergic effects: Can cause urinary retention, especially when combined with other anticholinergic medications 6
- Abuse potential: High-dose chronic use has been associated with cognitive impairment and withdrawal symptoms 7, 8
- Not for children <6 years without medical supervision: The over-the-counter formulation is not labeled for this age group 1
Administration Tips
- Take with food or water to minimize gastrointestinal upset
- For motion sickness, timing is critical—administer 30-60 minutes before departure 1
- Avoid alcohol and other CNS depressants due to additive sedative effects