dimenhydrinate

Contraindicated in:

Hypersensitivity;
Some products contain alcohol or tartrazine; in patients with known intolerance.

Use Cautiously in:

Angle-closure glaucoma;
Seizure disorders;
Prostatic hyperplasia.
Geri: Appears on Beers list. ↑ risk of anticholinergic adverse reactions in older adults, including falls, delirium, and dementia. Avoid use in older adults.

Adv. Reactions/Side Effects ⬆ ⬇

CV: hypotension, palpitations

Derm: photosensitivity

EENT: blurred vision, tinnitus

GI: anorexia, constipation, diarrhea, dry mouth

GU: dysuria, urinary frequency

Local: pain at IM site

Neuro: drowsiness, dizziness, headache, paradoxical excitation (children)

Interactions ⬆ ⬇

Drug-drug:

↑CNS depression with other antihistamines, alcohol, opioid analgesics, and sedative/hypnotics.
May mask signs or symptoms of ototoxicity in patients receiving ototoxic drugs (aminoglycosides, ethacrynic acid).
↑anticholinergic properties with tricyclic antidepressants, quinidine, or disopyramide.
MAO inhibitors intensify and prolong the anticholinergic effects of antihistamines.

Availability ⬆ ⬇

(Generic available)

Tablets: 50 mg^OTC
Chewable tabletsorange flavor: 50 mg^OTC
Solution for injection: 10 mg/mL; 50 mg/mL

Route/Dosage ⬆ ⬇

PO (Adults ): 50–100 mg every 4 hr (not to exceed 400 mg/day).
PO (Children 6–12 yr): 25–50 mg every 6–8 hr (not to exceed 300 mg/day).
IM IV (Adults ): 50 mg every 4 hr as needed.
IM IV (Children ): 1.25 mg/kg (37.5 mg/m²) every 6 hr as needed (not to exceed 300 mg/day).

US Brand Names ⬆ ⬇

Dramamine, Driminate

Action ⬆ ⬇

Inhibits vestibular stimulation.
Has significant CNS depressant, anticholinergic, antihistaminic, and antiemetic properties.

Therapeutic effects:

Decreased vestibular stimulation, which may prevent motion sickness.

Classifications ⬆ ⬇

Therapeutic Classification: antiemetics, antihistamines

Pharmacokinetics ⬆ ⬇

Absorption: Well absorbed after oral or IM administration. IV administration results in complete bioavailability.

Distribution: Extensively distributed to tissues.

Metabolism/Excretion: Metabolized by the liver.

Half-Life: Unknown.

Canadian Brand Names ⬆ ⬇

Time/Action Profile ⬆ ⬇

(antimotion sickness, antiemetic activity)

ROUTE	ONSET	PEAK	DURATION
PO	15–60 min	1–2 hr	3–6 hr
IM	20–30 min	1–2 hr	3–6 hr
IV	rapid	unknown	3–6 hr

Patient/Family Teaching ⬆ ⬇

Instruct patient to take dimenhydrinate as directed.
May cause drowsiness. Caution patient to avoid driving or other activities requiring alertness until response to the drug is known.
Inform patient that this medication may cause dry mouth. Frequent oral rinses, good oral hygiene, and sugarless gum or candy may minimize this effect.
Caution patient to avoid alcohol and other CNS depressants, including opioids, concurrently with this medication.
Advise patient to use sunscreen and protective clothing to prevent photosensitivity reactions.
Rep: Advise females of reproductive potential to notify health care professional if pregnancy is planned or suspected or if breastfeeding. May be used for treatment of pregnancy-associated nausea and vomiting. Monitor infants exposed to dimenhydrinate through breast milk for irritability or drowsiness.

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Indications ⬇

Contraind./Precautions ⬆ ⬇