DIMENHYDRINATE
(dye-men-hye'dri-nate)
Apo-Dimenhydrinate

, Calm-X, Dimenhydrinate Injection, Dimentabs, Dinate, Dommanate, Dramanate, Dramamine, Dramilin, Dramocen, Dramoject, Dymenate, Gravol

, Hydrate, Marmine, Motion-Aid, Nauseatol

, Novodimenate

, PMS Dimenhydrinate

, Travamine

, Travel Aid, Travel Eze, Wehamine
Classifications: antihistamine (h₁-receptor antagonist); antiemetic; antivertigo agent
Prototype: Diphenhydramine
Pregnancy Category: B

Availability

50 mg tablets; 50 mg/mL injection; 15.62 mg/5 mL, 12.5 mg/4 mL, 12.5 mg/5 mL liquid

Actions

H₁-receptor antagonist and salt of diphenhydramine, with which it shares similar properties.

Therapeutic Effects

Precise mode of antinauseant action not known, but thought to involve ability to inhibit cholinergic stimulation in vestibular and associated neural pathways.

Uses

Chiefly in prevention and treatment of motion sickness. Also has been used in management of vertigo, nausea, and vomiting associated with radiation sickness, labyrinthitis, Ménière's syndrome, stapedectomy, anesthesia, and various medications.

Contraindications

Narrow-angle glaucoma, prostatic hypertrophy. Safe use during pregnancy (category B), lactation, or in children <2 y is not established.

Cautious Use

Convulsive disorders.

Route & Dosage

Motion Sickness
Adult: PO 50–100 mg q4–6h (max: 400 mg/24 h) IV/IM 50 mg as needed
Child: PO 2–6 y, up to 25 mg q6–8h (max: 75 mg/24 h); 6–12 y, 25–50 mg q6–8h (max:150 mg/24 h) IV/IM 2–6 y, 1.25 mg/kg q.i.d. up to 300 mg/d; 6–12 y, 1.25 mg/kg q.i.d. up to 300 mg/d

Administration

Note: Give 30–60 min before treatment, then repeat 90 min after treatment, and again in 3 h to prevent radiation sickness.

Intramuscular

Give undiluted and inject deep IM into a large muscle.

Intravenous

PREPARE: Direct: Dilute each 50 mg in 10 mL of NS.

ADMINISTER: Direct: Give each 50 mg or fraction thereof over 2 min.

INCOMPATIBILITIES Solution/additive: Aminophylline, amobarbital, butorphanol, chlorpromazine, glycopyrrolate, hydroxyzine, midazolam, pentobarbital, prochlorperazine, promazine, promethazine, thiopental.

Store preferably at 15°–30° C (59°–86° F), unless otherwise directed by manufacturer.
Examine parenteral preparation for particulate matter and discoloration. Do not use unless absolutely clear.

Adverse Effects (1%)

CNS: Drowsiness, headache, incoordination, dizziness, blurred vision, nervousness, restlessness, insomnia (especially children). CV: Hypotension, palpitation. GI: Dry mouth, nose, throat; anorexia, constipation or diarrhea. Urogenital: Urinary frequency, dysuria.

Diagnostic Test Interference

Skin testing procedures should not be performed within 72 h after use of an antihistamine.

Interactions

Drug: Alcohol and other cns depressants enhance CNS depression, drowsiness; tricyclic antidepressants compound anticholinergic effects.

Pharmacokinetics

Absorption: Readily absorbed from GI tract. Onset: 15–30 min PO; immediate IV; 20–30 min IM. Duration: 3–6 h. Distribution: Distributed into breast milk. Elimination: Excreted in urine.

Nursing Implications

Assessment & Drug Effects

Use side rails and supervise ambulation; drug produces high incidence of drowsiness.
Note: Tolerance to CNS depressant effects usually occurs after a few days of drug therapy; some decrease in antiemetic action may result with prolonged use.
Monitor for dizziness, nausea, and vomiting; these may indicate drug toxicity.

Patient & Family Education

Do not drive or engage in other potentially hazardous activities until response to drug is known.
Take 30 min before departure to prevent motion sickness; repeat before meals and upon retiring.
Do not breast feed while taking this drug without consulting physician.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug