Nurses Compass
Drug Guide
Diphenidol Hydrochloride
Classification
Therapeutic: Anti-vertigo, Antiemetic
Pharmacological: Anticholinergic, Antihistaminic
FDA Approved Indications
- Vertigo associated with Meniere's disease
- Nausea and vomiting
Mechanism of Action
Diphenidol acts centrally to block vestibular afferent pathways and has anticholinergic and antihistaminic properties, which help reduce nausea, vomiting, and vertigo.
Dosage and Administration
Adult: Typically 50-75 mg 3 times daily, or as directed by a physician; dosage adjustments may be needed based on response.
Pediatric: Use is generally not recommended for children due to limited data.
Geriatric: Start at lower doses due to increased sensitivity and potential for adverse effects; monitor closely.
Renal Impairment: Adjust dose based on renal function, if necessary.
Hepatic Impairment: Use with caution; monitor liver function.
Pharmacokinetics
Absorption: Well absorbed orally.
Distribution: Widely distributed in body tissues.
Metabolism: Metabolized in the liver.
Excretion: Excreted primarily in urine and feces.
Half Life: Approximately 4-6 hours.
Contraindications
- Hypersensitivity to diphenidol or other components.
- Narrow-angle glaucoma.
- Present or past history of prostatic hypertrophy with urinary retention.
Precautions
- Use cautiously in patients with liver or kidney impairment.
- May cause drowsiness; caution when driving or operating machinery.
- Pregnancy and lactation: consult healthcare provider before use.
Adverse Reactions - Common
- Drowsiness (Common)
- Dry mouth (Common)
- Dizziness (Common)
Adverse Reactions - Serious
- Urinary retention (Rare)
- Blurred vision (Rare)
- Hypersensitivity reactions (Rare)
Drug-Drug Interactions
- Additive CNS depression with other sedatives, alcohol, or hypnotics.
Drug-Food Interactions
N/ADrug-Herb Interactions
N/ANursing Implications
Assessment: Monitor for therapeutic effectiveness and adverse effects such as drowsiness, dry mouth, urinary retention.
Diagnoses:
- Risk for falls related to dizziness or drowsiness.
- Impaired urinary elimination.
Implementation: Administer with meals if gastrointestinal upset occurs; avoid operating heavy machinery until response is known.
Evaluation: Assess reduction in vertigo and nausea, monitor adverse effects.
Patient/Family Teaching
- Take medication exactly as prescribed.
- Avoid alcohol and CNS depressants.
- Report any signs of urinary retention, severe dizziness, or allergic reactions.
- Do not operate heavy machinery until sedative effects are known.
Special Considerations
Black Box Warnings:
- None
Genetic Factors: None identified.
Lab Test Interference: None known.
Overdose Management
Signs/Symptoms: Severe anticholinergic effects such as dry mouth, dilated pupils, hallucinations, urinary retention, tachycardia, confusion.
Treatment: Supportive care; no specific antidote. Activated charcoal may be used if ingestion was recent; symptom management includes cooling measures for hyperthermia and IV fluids.
Storage and Handling
Storage: Store at room temperature, away from moisture and light.
Stability: Stable under recommended storage conditions.