• Motion sickness.
• Vertigo associated with diseases of the vestibular system.

Contraindicated in:

• Hypersensitivity.

Use Cautiously in:

• Prostatic hyperplasia
• Angle-closure glaucoma
• Lactation: Use while breastfeeding only if potential maternal benefit justifies potential risk to infant
• Pedi: Children <12 yr (safety and effectiveness not established)
• Geri: Appears on Beers list. ↑ risk of anticholinergic adverse reactions in older adults, including falls, delirium, and dementia. Avoid use in older adults.

EENT: blurred vision.

GI: dry mouth.

Neuro: drowsiness, fatigue.

Drug-Drug:

• Additive CNS depression with other CNS depressants, including alcohol, other antihistamines, opioid analgesics, and sedative/hypnotics.
• Additive anticholinergic effects with other drugs possessing anticholinergic properties, including some antihistamines, antidepressants, atropine, haloperidol, phenothiazines, quinidine, and disopyramide.
• CYP2D6 inhibitors may ↑ levels and risk of toxicity

(Generic available)

• Tablets: 12.5 mg; 25 mg^{Rx, OTC}; 50 mg;
• Chewable tablets (raspberry flavor): 25 mg^OTC;

• PO (Adults and Children ≥12 yr): Motion sickness: 25–50 mg 1 hr before exposure; may repeat in 24 hr; Vertigo: 25–100 mg/day in divided doses.

Antivert, Bonine

• Has central anticholinergic, CNS depressant, and antihistaminic properties.
• Decreases excitability of the middle ear labyrinth and depresses conduction in middle ear vestibular-cerebellar pathways.

• Decreased motion sickness.
• Decreased vertigo from vestibular pathology.

Therapeutic Classification: antiemetics, antihistamines

Absorption: Absorbed after oral administration.

Distribution: Unknown.

Metabolism/Excretion: Primarily metabolized by liver via the CYP2D6 isoenzyme; the CYP2D6 isoenzyme exhibits genetic polymorphism (7% of population may be poor metabolizers and may have significantly ↑ meclizine concentrations and an ↑ risk of adverse effects).

Half-life: 6 hr.

(antihistaminic effects)

• Instruct patient to take meclizine exactly as directed. If a dose is missed, take as soon as possible unless almost time for next dose. Do not double doses.
  • May cause drowsiness. Caution patient to avoid driving or other activities requiring alertness until response to the medication is known.
  • Advise patient that frequent mouth rinses, good oral hygiene, and sugarless gum or candy may decrease dryness of mouth.
  • Caution patient to avoid concurrent use of alcohol and other CNS depressants, including opioids, with this medication.
  • Advise females of reproductive potential to notify health care professional if pregnancy is planned or suspected, or if breastfeeding.
• Motion Sickness: When used as prophylaxis for motion sickness, advise patient to take medication at least 1 hr before exposure to conditions that may cause motion sickness.

MEK-li-zeen