Meclizine (Bonine): What It Is and How It's Used for Motion Sickness

Educational summary · drug class: First-generation (sedating) antihistamine, piperazine class, with anticholinergic activity; antiemetic/antivertigo agent · last reviewed 2026-06-29

What it is

Meclizine hydrochloride (spelled meclozine in the UK and elsewhere) is a first-generation, sedating antihistamine of the piperazine class that also has anticholinergic properties, used as an antiemetic and antivertigo agent. In the US it is available both over the counter (e.g., Bonine, Dramamine Less Drowsy) and by prescription (e.g., Antivert). Other names include D-Vert, Zentrip, and (internationally) Postafen. In the UK the meclozine brand Sea-Legs has been discontinued. Status and availability vary by country and product.

Availability: Both — OTC (e.g., Bonine, Dramamine Less Drowsy) and Rx (e.g., Antivert) in the US; varies by country and product. Legal status, brand names, and availability vary by country — check what applies where you live.

How it may help with motion sickness

Motion sickness arises when the inner ear's balance organs and the eyes send conflicting signals. The FDA label describes meclizine as an antihistamine with marked protective activity against histamine and only slight blocking action against acetylcholine. By acting on histamine and cholinergic pathways involved in the brain's nausea, vomiting, and balance signaling, it is thought to dampen the nausea, vomiting, and dizziness this sensory conflict produces. It works best when taken before symptoms start.

General timing

According to the FDA/DailyMed label and MedlinePlus, the initial dose is generally taken about 1 hour before travel for protection against motion sickness, and may be repeated about every 24 hours for the duration of the journey because of its long action. This is general label timing only. We do not provide dosing instructions — follow the product label or the advice of your doctor or pharmacist.

We don't provide dosing instructions. The exact amount, schedule, and whether it suits you are individual decisions — read the product label and follow its directions, and ask a doctor or pharmacist.

Common side effects

Sources such as the product label commonly list:

• Drowsiness
• Dry mouth
• Tiredness or fatigue
• Dizziness
• Blurred vision (reported on rare occasions; report it to a doctor)

Who should check with a doctor or pharmacist first

• Drowsiness is common; the label warns against driving or operating dangerous machinery until you know how it affects you. 'Less drowsy' branding does not mean drowsiness-free.
• Avoid alcohol; it and other CNS depressants (sedatives, sleep aids, opioids, muscle relaxants, anxiety or depression medicines) can add to drowsiness.
• Pregnancy: FDA Pregnancy Category B; the label advises use only if clearly necessary. Talk to a clinician first.
• Children: the FDA label states use is not recommended in children under 12.
• Older adults: MedlinePlus and the Beers Criteria note older adults should usually avoid meclizine, as safer or more effective alternatives exist, due to anticholinergic effects.
• Use with care if you have asthma, glaucoma, an enlarged prostate, or urinary or bladder obstruction; consult a clinician first.
• Avoid if you have a known allergy to meclizine.
• A doctor or pharmacist should review individual suitability and interactions.

Frequently asked questions

This page is for general educational and informational purposes only. It is not medical advice and is not a substitute for the advice of a qualified healthcare professional. Dizzout is not a medical provider — we are not doctors or pharmacists. The information here is a general summary drawn from sources such as the FDA-approved label and other public health resources, and it may not reflect the most current changes; the official product label is the authoritative source. Whether any medicine is right for you, and how much to take, are individual decisions that depend on your health, age, and other medicines. We do not provide dosing instructions — always read the product label and follow its directions. Talk to your doctor or pharmacist before starting, stopping, or changing any medication, and never disregard or delay professional medical advice because of something you read here. If you think you may have a medical emergency, contact a doctor or your local emergency number immediately.