Nurses Compass
Drug Guide
Dimenhydrinate
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/ADrug-Herb Interactions
N/ANursing 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