Meclizine

Meclizine is an antihistamine used for two main purposes across its many available products.

• Motion sickness: Prevention and treatment of nausea, vomiting, and dizziness caused by motion sickness — supported across all meclizine products, including Bonine, Bonine Max, Dramamine, Dramamine Less Drowsy, Dramamine-N, Naus-ease, CVS Motion Sickness Fast Melting, Wal-Dram 2 Quick-Dissolving, Meclizine HCL, and others.
• Vertigo: Treatment of vertigo (a spinning or whirling sensation) associated with diseases affecting the vestibular system — the inner ear balance system — in adults. This is an indication for prescription meclizine hydrochloride tablets, as well as Naus-ease tablets and film strips.

Meclizine is thought to work primarily by blocking histamine H1 receptors — sites in the body where histamine normally binds and triggers responses like nausea, vomiting, and dizziness. By blocking these receptors, meclizine helps calm those symptoms. The exact full mechanism isn't completely understood, but this antihistamine action is considered the core of how it helps with motion sickness and vestibular-related dizziness. Meclizine also has anticholinergic properties, meaning it can block certain nerve signals, which may contribute to both its effects and some of its side effects.

Meclizine is taken by mouth. For motion sickness, take it about one hour before travel and then once every 24 hours as needed during the trip. For vertigo, prescription meclizine hydrochloride tablets are taken in divided doses daily, as directed by your doctor — the amount depends on how well the condition is responding.

• Standard tablets: Swallow whole — never chew or crush.
• Chewable tablets (Bonine, Bonine Max, Dramamine, Dramamine Chewable Orange, Meclizine HCL): Must be fully chewed or crushed before swallowing — never swallowed whole.
• Naus-ease film strips: Place on the tongue and let it dissolve completely, then swallow.
• Always follow your prescriber's instructions or the package directions. Do not take more than directed.

Most people taking meclizine experience mild side effects. The most commonly reported ones include:

• Drowsiness — the most frequent effect
• Dry mouth
• Headache
• Fatigue
• Vomiting
• Blurred vision (rare)

Rarely, a serious allergic reaction called anaphylaxis can occur — signs include hives, throat swelling, or difficulty breathing. Seek emergency medical help immediately if this happens.

• Drowsiness: Meclizine commonly causes sleepiness. Avoid driving a car or operating dangerous machinery until you know how it affects you.
• Alcohol: Do not drink alcohol while taking meclizine — it significantly increases sedation.
• Asthma, glaucoma, or enlarged prostate: Meclizine's anticholinergic action may worsen these conditions. Use with caution and tell your doctor.
• Liver or kidney impairment: These conditions can slow how your body clears meclizine, leading to higher drug levels. Use cautiously.
• Older adults: Extra caution is needed, as kidney function naturally declines with age, which may cause the drug or its breakdown products to accumulate.

Meclizine can interact with several substances that affect how it works or amplify its side effects.

• Alcohol: Increases CNS (central nervous system) depression — can cause significant extra drowsiness and impaired coordination.
• Other CNS depressants (sleep medications, anti-anxiety drugs, opioid pain relievers, muscle relaxants): When combined with meclizine, these can cause additive sedation that may be unsafe.
• CYP2D6 inhibitors (certain antidepressants, some antifungals, and other drugs that inhibit this liver enzyme): Since meclizine is metabolized by the CYP2D6 enzyme, these drugs may raise meclizine levels in the blood, potentially increasing side effects. Tell your doctor and pharmacist about all medications you take.

This is not a complete list of interactions. Always talk with your doctor or pharmacist before starting, stopping, or changing any medication.

• Allergy: Do not take meclizine if you are allergic to it or to any inactive ingredients in the product.
• Asthma, glaucoma, or enlarged prostate: Tell your doctor — meclizine's anticholinergic effects can aggravate these conditions.
• Pregnancy: Human studies have not shown a clear increased risk of birth defects, but animal studies showed fetal harm at doses similar to those used in humans. Discuss the risks and benefits with your doctor before taking meclizine during pregnancy.
• Breastfeeding: It is not known whether meclizine passes into breast milk or how it might affect a nursing infant. Talk to your doctor before using.
• Children under 12: Safety and effectiveness have not been established. Most OTC labels instruct not to give meclizine to children under 12 without a doctor's direction.
• Older adults: Start at the lower end of the dosing range. Reduced kidney and liver function with age means the drug may stay in the body longer.
• Liver impairment: Meclizine is processed by the liver; impairment may increase drug exposure. Use with caution.
• Kidney impairment: Reduced kidney function may cause meclizine or its breakdown products to accumulate. Use with caution.

After taking meclizine by mouth, it is absorbed through the digestive tract, with blood levels typically peaking around 3 hours after a dose (range: 1.5 to 6 hours) for tablet forms. Meclizine has a plasma elimination half-life — the time it takes for half the drug to be cleared from the blood — of about 5 to 6 hours. It is primarily broken down in the liver by an enzyme called CYP2D6, which means that drugs affecting this enzyme can alter how much meclizine stays active in your system. How meclizine distributes throughout body tissues is not well characterized in humans.

Store at 20° to 25°C (68° to 77°F) . Dispense in a tight, light-resistant container (USP).