What is the recommended dosage and treatment plan for meclozine (Antivert) in treating vertigo and motion sickness?

Meclizine (Antivert) Dosage and Treatment Plan for Vertigo and Motion Sickness

For vertigo and motion sickness, meclizine (Antivert) should be administered at a dose of 25 mg orally every 24 hours for vertigo, or 25-50 mg taken 1 hour before travel for motion sickness, with doses repeated every 24 hours as needed during travel.

Dosage Recommendations

For Vertigo

• Standard dose: 25 mg orally once daily
• Duration: Continue until symptoms resolve, typically 3-7 days
• Onset of action: Approximately 1 hour after oral administration 1
• Peak plasma concentration: Occurs around 49-70 minutes after oral dosing 2

For Motion Sickness

• Preventive dose: 25-50 mg orally
• Timing: Take 1 hour before anticipated travel/motion exposure
• Maintenance: May repeat every 24 hours as needed during continued travel
• Note: Most effective when taken prophylactically rather than after symptoms begin

Efficacy and Comparative Effectiveness

• Meclizine has been shown to be equally effective as diazepam in treating acute peripheral vertigo in emergency department settings 3
• Studies have demonstrated that meclizine is significantly superior to placebo in preventing motion sickness 4
• For acute vertigo, meclizine has comparable efficacy to transdermal scopolamine 4

Special Considerations

Elderly Patients

• Consider starting at lower doses (12.5 mg) due to increased sensitivity to anticholinergic effects
• Monitor for increased risk of sedation and cognitive impairment

Formulation Options

• Standard oral tablets are available but have a slower onset of action
• A suspension formulation (MOS) shows more rapid absorption with similar overall bioavailability compared to tablets 1
• Consider the suspension formulation when faster symptom relief is needed

Duration of Treatment

• For acute vertigo: Use until symptoms resolve, typically 3-7 days
• For motion sickness: Use only during travel or exposure to motion triggers
• Avoid prolonged use when possible to minimize side effects

Common Side Effects and Precautions

• Common side effects: Drowsiness, dry mouth, blurred vision
• Less common: Urinary retention, confusion (especially in elderly)
• Precautions:
  • Use with caution in patients with glaucoma, prostatic hypertrophy, or bladder obstruction
  • Avoid alcohol and other CNS depressants which may enhance sedative effects
  • May impair ability to drive or operate machinery

Alternative Treatments

• For BPPV specifically, canalith repositioning procedures (Epley maneuver) should be considered as first-line treatment rather than medication 5
• For severe cases not responding to meclizine, transdermal scopolamine may be considered as an alternative 4
• Vestibular rehabilitation may be offered as adjunctive therapy for residual symptoms 5

Treatment Algorithm

1. Confirm diagnosis: Determine if symptoms are consistent with peripheral vertigo (BPPV) or motion sickness
2. For BPPV: Consider canalith repositioning procedures as first-line treatment
3. For medication treatment:
   • Start with meclizine 25 mg orally
   • If inadequate response after 1-2 days, may increase to 50 mg daily
   • If drowsiness is problematic, reduce to 12.5 mg and take at bedtime
4. For motion sickness prevention:
   • Take 25-50 mg one hour before travel
   • Continue daily dosing throughout duration of travel if needed
5. Follow-up: Reassess within 1 month for vertigo to confirm symptom resolution 5