dimenhydrinate, combinations

R06AA61

Forms & Strengths

Tablets: Dimenhydrinate combined with agents like caffeine, cinnarizine, or pyridoxine (strengths vary by combination product)
Suppositories: Combination formulations available in select regions

Adult Dosing

Motion sickness / Vertigo: Typically 50 mg to 100 mg orally every 4 to 6 hours as needed, not to exceed maximum daily limits specified by the specific combination product labeling
Max dose: Generally not to exceed 400 mg daily for dimenhydrinate component

Pediatric Dosing

Children 6 to 12 years: 25 mg to 50 mg orally every 6 to 8 hours as needed, adjusted based on specific combination product guidelines
Children under 6 years: Use only as directed by a pediatrician; generally not recommended for certain fixed-dose combinations containing stimulants or additional active ingredients

Indications

Prevention and treatment of nausea, vomiting, dizziness, or vertigo associated with motion sickness
Management of inner ear disorders (e.g., Meniere's disease) presenting with vertigo and associated autonomic symptoms

Mechanism of Action

Dimenhydrinate is the chlorteophylline salt of diphenhydramine; acts as a first-generation antihistamine with central anticholinergic, sedative, and antiemetic properties
Antagonizes H1 receptors in the central nervous system and peripherally, and depresses labyrinthine function and the chemoreceptor trigger zone
Combinations often include stimulants (e.g., caffeine) to counteract sedation or vasodilators (e.g., cinnarizine) for enhanced labyrinthine suppression

Contraindications

Hypersensitivity to dimenhydrinate, diphenhydramine, theophylline derivatives, or any component of the specific combination
Severe hepatic or renal impairment (depending on combination ingredients)
Narrow-angle glaucoma, symptomatic prostatic hyperplasia, gastrointestinal or urinary bladder neck obstruction
Neonates and premature infants

Adverse Reactions

Drowsiness, sedation, fatigue, and dizziness
Anticholinergic effects: dry mouth, blurred vision, urinary retention, and constipation
Paradoxical excitation in pediatric patients
Gastrointestinal upset, nausea, or headache

Drug Interactions

Central nervous system depressants (alcohol, barbiturates, tranquilizers, opioids): potentiation of sedative effects
Drugs with significant anticholinergic properties (tricyclic antidepressants, MAO inhibitors): enhanced anticholinergic toxicity
Ototoxic medications (aminoglycosides): dimenhydrinate may mask early signs of ototoxicity
Stimulant combinations may interact with sympathomimetics or alter cardiovascular parameters

Curated Content: Needs Vetting Before Put to Clinical Use