Meclizine Dosing
The FDA-approved dosing for meclizine is 25 to 100 mg daily administered orally in divided doses, with tablets swallowed whole. 1
Standard Adult Dosing
- The recommended adult dose ranges from 25 mg to 100 mg daily, divided throughout the day based on clinical response. 1
- For motion sickness and vertigo, the typical starting dose is 25 mg, which can be increased up to 100 mg daily if needed. 1
- In emergency department studies comparing meclizine to diazepam for acute peripheral vertigo, a single 25 mg oral dose was used and demonstrated equivalent efficacy. 2
Pediatric Dosing Considerations
There is no FDA-approved pediatric dosing for meclizine for standard indications (motion sickness, vertigo). However, emerging research provides some guidance:
- In children with achondroplasia aged 5-10 years, doses of 12.5 mg daily (for children <20 kg) and 25 mg daily (for children ≥20 kg) were well-tolerated with no serious adverse events after 14 days of administration. 3
- Peak plasma concentrations (Cmax) in children occurred at approximately 3.7 hours after dosing, with a terminal elimination half-life of 7.4 hours. 3
- Steady-state plasma concentrations were achieved around 10 days after initiating daily dosing. 4
- Food increases meclizine exposure significantly - the AUC in fed conditions was 813 ng·h/mL compared to 504 ng·h/mL in fasting conditions, representing a 61% increase. 4
Administration Guidelines
- Tablets must be swallowed whole and should not be crushed or chewed. 1
- Administration with food increases drug absorption and may improve tolerability. 4
- For motion sickness prevention, meclizine should be taken 1 hour before travel based on its pharmacokinetic profile showing peak levels at 1.7-3.7 hours. 3, 4
Common Pitfalls to Avoid
- Do not confuse meclizine with mexiletine (an antiarrhythmic agent) - these are completely different medications with similar names. 5, 6
- Avoid exceeding 100 mg daily without clear clinical justification, as the FDA label specifies this as the upper dosing range. 1
- Do not use meclizine as first-line therapy for anaphylaxis or severe allergic reactions - it is not indicated for these conditions and epinephrine remains the only appropriate first-line treatment. 7
- In pediatric patients, recognize that meclizine lacks extensive safety data for routine use in children, and the available pediatric data comes primarily from achondroplasia studies rather than motion sickness or vertigo indications. 3, 4