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RESPIRATORY SYSTEM › ANTIHISTAMINES FOR SYSTEMIC USE › ANTIHISTAMINES FOR SYSTEMIC USE › Aminoalkyl ethers
dimenhydrinate
R06AA11
Forms & Strengths
- Tablet: 50 mg
- Liquid: 12.5 mg/4 mL, 15 mg/5 mL
- Injection: 50 mg/mL
Adult Dosing
- Motion sickness: 50 to 100 mg orally every 4 to 6 hours as needed; max 400 mg/day
- IV/IM: 50 mg diluted in 10 mL NS administered over at least 2 minutes every 4 to 6 hours as needed
Pediatric Dosing
- Children 2 to 6 years: 12.5 to 25 mg orally every 6 to 8 hours as needed; max 75 mg/day
- Children 6 to 12 years: 25 to 50 mg orally every 6 to 8 hours as needed; max 150 mg/day
- Children > 12 years: 50 to 100 mg orally every 4 to 6 hours as needed; max 400 mg/day
Indications
- Prevention and treatment of nausea, vomiting, and dizziness associated with motion sickness
Mechanism of Action
- Classic antihistamine containing diphenhydramine and 8-chlorotheophylline
- Competitively blocks central histamine H1 receptors in the vestibular system and chemoreceptor trigger zone to suppress nausea and vomiting
- Exhibits significant central and peripheral anticholinergic, sedative, and local anesthetic properties
Contraindications
- Hypersensitivity to dimenhydrinate, diphenhydramine, orophylline, or any component of the formulation
- Neonates or premature infants due to paradoxical central excitation and susceptibility to anticholinergic toxicity
- Concomitant use with monoamine oxidase inhibitors (MAOIs)
Adverse Reactions
- Central nervous system: Drowsiness, sedation, dizziness, headache, paradoxical excitation in children
- Anticholinergic: Xerostomia, blurred vision, urinary retention, constipation
- Cardiovascular: Palpitations, tachycardia, hypotension
- Respiratory: Thickening of bronchial secretions
Drug Interactions
- Central nervous system depressants (alcohol, opioids, sedatives, hypnotics): Enhances sedative and CNS depressant effects
- Anticholinergic agents (antipsychotics, tricyclic antidepressants): Increases risk of severe anticholinergic side effects
- Ototoxic medications (aminoglycosides, platinum compounds): May mask early signs of ototoxicity due to vestibular suppression
Curated Content: Needs Vetting Before Put to Clinical Use