Home Drug Guide Dimenhydrinate

Drug Guide

Generic Name

Dimenhydrinate

Brand Names Dramamine

Classification

Therapeutic: Antiemetic, Antivertigo agent

Pharmacological: Antihistamine (H1 receptor antagonist)

FDA Approved Indications

Motion sickness
Nausea and vomiting

Mechanism of Action

Dimenhydrinate blocks H1 histamine receptors in the central nervous system, leading to sedation and reduction of nausea and dizziness.

Dosage and Administration

Adult: 50-100 mg every 4-6 hours as needed, not exceeding 400 mg/day

Pediatric: Not generally recommended for children under 2 years; for older children, dose based on weight and age, typically 25-50 mg every 6-8 hours

Geriatric: Start at lower doses due to increased sensitivity; monitor for anticholinergic effects

Renal Impairment: Adjust dose based on severity of impairment, use cautiously

Hepatic Impairment: Use with caution; dose adjustment may be necessary

Pharmacokinetics

Absorption: Well absorbed after oral administration

Distribution: Widely distributed throughout body tissues, crosses the blood-brain barrier

Metabolism: Metabolized in the liver

Excretion: Excreted mainly in urine as unchanged drug and metabolites

Half Life: Approximately 4-8 hours

Contraindications

Hypersensitivity to dimenhydrinate or other antihistamines
Glaucoma (narrow-angle)
Bladder neck obstructions
Prostatic hypertrophy

Precautions

Use with caution in elderly, patients with CV disease, asthma, or seizure disorders; may cause drowsiness, dizziness, or anticholinergic side effects

Adverse Reactions - Common

Drowsiness (Common)
Dizziness (Common)
Dry mouth (Common)
Blurred vision (Less common)

Adverse Reactions - Serious

Palpitations (Rare)
Allergic reactions (rash, difficulty breathing) (Rare)
Confusion or hallucinations in elderly (Rare)

Drug-Drug Interactions

CNS depressants (enhanced sedation)
Monoamine oxidase inhibitors (risk of hypertensive crisis)

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor for effectiveness in controlling nausea and vertigo; observe for adverse effects like drowsiness or anticholinergic symptoms

Diagnoses:

Risk for injury due to sedation or dizziness
Impaired safety due to anticholinergic effects

Implementation: Administer with food if GI upset occurs; caution patient about operating machinery

Evaluation: Assess symptom relief and monitor for adverse reactions

Patient/Family Teaching

Avoid driving or operating heavy machinery while taking medication
Caution about alcohol and CNS depressants use
Report any severe side effects or allergic reactions

Special Considerations

Black Box Warnings: N/A

Genetic Factors: N/A

Lab Test Interference: N/A

Overdose Management

Signs/Symptoms: Severe drowsiness, hallucinations, seizures, tachycardia, urinary retention

Treatment: Supportive care; gastric lavage if within 1 hour of ingestion; administer activated charcoal; monitor cardiac and respiratory status; symptomatic treatment

Storage and Handling

Storage: Store at room temperature, away from light and moisture

Stability: Stable for 2-3 years when stored properly