Meclizine Dosage for Adults
The recommended dosage of meclizine for adults is 25 mg to 100 mg daily, administered orally in divided doses, depending upon clinical response. 1
Dosage Guidelines
Meclizine is an antihistamine commonly used for the treatment of vertigo associated with diseases affecting the vestibular system in adults. The FDA-approved dosing provides clear guidance:
- Standard adult dose range: 25-100 mg daily 1
- Typical starting dose: 25 mg 1
- Administration: Can be given in divided doses throughout the day 1
- Dosage forms available: 12.5 mg, 25 mg, and 50 mg tablets 1
Clinical Considerations
Timing of Administration
- Meclizine can be taken with food to improve tolerance 1
- When used for motion sickness, it's most effective when taken approximately 1 hour before travel 2
- Peak plasma concentration (Tmax) occurs approximately 3.7 hours after administration 3
Duration of Effect
- The terminal elimination half-life is approximately 7.4 hours 3
- Steady-state plasma concentration is typically achieved after approximately 10 days of regular dosing 4
Special Populations
Elderly Patients
- Consider starting at the lower end of the dosage range (25 mg) due to potential increased sensitivity to anticholinergic effects 1
Patients with Renal or Hepatic Impairment
- No specific dosage adjustments are provided in the FDA labeling, but caution is advised due to potential drug accumulation 1
Important Warnings and Precautions
- Drowsiness: Patients should be warned about potential drowsiness and cautioned against driving or operating dangerous machinery 1
- Alcohol: Patients should avoid alcoholic beverages while taking meclizine due to increased CNS depression 1
- Concurrent medical conditions: Use with caution in patients with asthma, glaucoma, or enlargement of the prostate gland due to potential anticholinergic effects 1
Common Adverse Effects
- Drowsiness
- Dry mouth
- Headache
- Fatigue
- Vomiting
- Rarely: blurred vision 1
Drug Interactions
- CNS depressants: Increased CNS depression when administered concurrently with other CNS depressants, including alcohol 1
- CYP2D6 inhibitors: Meclizine is metabolized by CYP2D6, so monitor for adverse reactions when used with CYP2D6 inhibitors 1
Remember that while meclizine is effective for vertigo management, the onset of action is typically about 1 hour, which may be important to consider when treating acute symptoms 5.