Drug information of Meclizine


A histamine H1 antagonist used in the treatment of motion sickness, vertigo, and nausea during pregnancy and radiation sickness.

Mechanism of effect

Along with its actions as an antagonist at H1-receptors, meclizine also possesses anticholinergic, central nervous system depressant, and local anesthetic effects. Meclizine depresses labyrinth excitability and vestibular stimulation and may affect the medullary chemoreceptor trigger zone.


Meclizine is used in the management of nausea, vomiting, and dizziness associated with motion sickness and vertigo in diseases affecting the vestibular apparatus.


Onset: 30-60 min 

Duration: 12-24 hr 

Peak plasma time: 3 hr 

Vd: 7 L/kg 

Metabolism: In vitro study found CYP2D6 the dominant metabolic enzyme

Half-life: 5 hr

Excretion: Urine, feces


Genetic polymorphism of CYP2D6 that results in extensive-, poor-, intermediate- and ultrarapid metabolizer phenotypes could contribute to large interindividual variability in meclizine exposure

Drug indications

vertigo , Motion sickness



Motion Sickness

12.5-50 mg PO given 1 hour before travel and then every 24 hr PRN


25-100 mg/day PO in single daily dose or divided q6-12hr


Motion Sickness

<12 years: Safety and efficacy not established

>12 years: 12.5-50 mg PO given 1 hour before travel and then daily PRN


<12 years: Safety and efficacy not established

>12 years: 25-100 mg/day PO in single daily dose or divided q6-12hr

Drug contraindications



Use cautioin in obstructive genitourinary tract disease, asthma, pyloric or duodenal obstruction, prostatic hyperplasia, narrow angle glaucoma

Hepatic impairment may increase meclizine systemic exposure

Renal impairment may increase meclizine or metabolite accumulation

May impair physical or mental abilities; use caution when operating heavy machinery or performing tasks which require mental alertness

Points of recommendation

Use meclizine exactly as directed by your doctor. Follow all directions on your prescription label. Do not take this medicine in larger or smaller amounts or for longer than recommended.

The chewable tablet must be chewed before you swallow it.

To prevent motion sickness, take meclizine about 1 hour before you travel or engage in activity that causes motion sickness. You may take a dose once every 24 hours while you are traveling, to further prevent motion sickness.

This medication can affect the results of allergy skin tests. Tell any doctor who treats you that you are using meclizine.

Store at room temperature away from moisture, heat, and light.

Since meclizine is sometimes taken only when needed, you may not be on a dosing schedule. If you are taking the medication regularly, take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

Pregnancy level


category B

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