Meclizine (Antivert) Dosing Recommendations
The recommended dosage for meclizine (Antivert) is 25 mg to 100 mg daily administered orally in divided doses, depending upon clinical response. 1
Indication and Administration
- Meclizine is indicated for the treatment of vertigo associated with diseases affecting the vestibular system in adults 1
- Tablets must be swallowed whole 1
- Available in 12.5 mg, 25 mg, and 50 mg tablet strengths 1
Dosing Guidelines
- Initial dosing: Start with 25 mg orally 1
- Frequency: Can be administered in divided doses throughout the day based on symptom control 1
- Maximum daily dose: Up to 100 mg daily 1
- For acute vertigo episodes, 25-50 mg may be administered as a single dose 2
Special Populations
- Elderly patients: Consider starting at lower doses due to increased risk of anticholinergic effects 1
- Pediatric patients: Safety and efficacy not well established in FDA labeling for standard vertigo indications 1
- In research settings, 12.5 mg daily has been used in children weighing <20 kg and 25 mg daily in children ≥20 kg 3
Pharmacokinetics
- Onset of action: Effects typically begin within 1 hour of oral administration 4
- Peak plasma concentration: Occurs approximately 3-4 hours after oral administration 3
- Half-life: Approximately 6-8 hours 3
- Duration of action: Effects may last 8-24 hours, allowing for once or twice daily dosing 4
Warnings and Precautions
- May cause drowsiness; patients should be cautioned against driving or operating dangerous machinery 1
- Avoid concurrent use with alcohol or other CNS depressants as this may increase sedation 1
- Use with caution in patients with asthma, glaucoma, or enlargement of the prostate gland due to potential anticholinergic effects 1
- Common adverse effects include drowsiness (up to 20%), dry mouth (50-60%), headache, and fatigue 1, 5
Comparative Efficacy
- Meclizine has shown similar efficacy to diazepam in treating acute peripheral vertigo in emergency department settings 2
- Meclizine is less effective than transdermal scopolamine for motion sickness prevention but has fewer adverse effects 5
- Meclizine has been used successfully to treat withdrawal symptoms after discontinuation of transdermal scopolamine therapy 6
Clinical Pearls
- For faster onset of action in acute vertigo, consider administering the full daily dose at once rather than dividing it 2
- If vertigo is severe and unresponsive to oral meclizine alone, combination therapy with other antivertigo medications may be considered 5
- Patients should be advised that tolerance to the sedative effects often develops within a few days of regular use 1
- For prevention of motion sickness, administer at least 1 hour before travel 5
Remember that meclizine is primarily indicated for vertigo associated with vestibular disorders and should be prescribed at the lowest effective dose to minimize side effects.