Cyclizine: What It Is and How It's Used for Motion Sickness
Educational summary · drug class: First-generation (sedating) antihistamine, piperazine derivative, with antimuscarinic activity; antiemetic · last reviewed 2026-06-29
Cyclizine is a first-generation (sedating) antihistamine with antimuscarinic activity used to help prevent and reduce the nausea, vomiting, and dizziness of motion sickness. The NHS directs taking it about 1 to 2 hours before travel. In the UK it is available both over the counter and on prescription, but in the US the cyclizine brand Marezine has been discontinued and it is not generally available. It causes drowsiness and is not for everyone.
Not medical advice. 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.
What it is
Cyclizine is a first-generation, sedating antihistamine of the piperazine-derivative class (an H1-receptor antagonist) that also has antimuscarinic (anticholinergic) properties, used as an antiemetic. It is sold in the UK and some markets as Valoid; the former US brand Marezine has been discontinued. In the UK it is available both from a pharmacy and on prescription. In the US it is no longer generally marketed, and OTC motion-sickness products there typically use meclizine or dimenhydrinate instead. Confirm current local availability with a clinician or pharmacist.
Availability: UK: pharmacy and prescription. US: not generally available (Marezine discontinued). Confirm locally. 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 brain receives conflicting balance signals from the inner ear and the eyes. Cyclizine blocks histamine H1 receptors in the brain and also has antimuscarinic activity; according to the NHS and the UK SmPC, these actions dampen signaling in the vestibular pathways and the brain's vomiting center, helping to prevent or reduce nausea, vomiting, and dizziness.
General timing
The NHS directs taking cyclizine for motion sickness about 1 to 2 hours before travel, with the option of further doses during a longer journey if needed; historic US Marezine labeling described a first dose roughly 30 to 60 minutes before departure. These are general label and guideline statements only. We do not provide dosing instructions — follow the current product leaflet 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 or sleepiness
- Dry mouth
- Blurred vision
- Constipation
- Headache
- Dizziness
- Less commonly: rapid heartbeat, urinary retention, low blood pressure, or restlessness
Who should check with a doctor or pharmacist first
- Pregnancy: the UK SmPC states use is not advised without definitive human data; discuss with a clinician.
- Breastfeeding: cyclizine passes into breast milk; seek medical advice.
- Children: UK tablets are not recommended for children under 6; pediatric use should follow the leaflet or professional advice.
- Older adults: more vulnerable to anticholinergic effects (confusion, memory problems) and to drops in blood pressure; use with care.
- Do not drive, cycle, or operate heavy machinery if it makes you drowsy or dizzy.
- Avoid alcohol — it adds to sedation; cyclizine is contraindicated in acute alcohol intoxication.
- Other CNS depressants and anticholinergic medicines (including some antidepressants) can add to its effects.
- Use with caution in glaucoma, urinary retention or prostate enlargement, gastrointestinal obstruction, epilepsy, severe heart failure or recent heart attack, liver disease, high blood pressure, and phaeochromocytoma.
- Avoid if you are allergic to cyclizine. Cyclizine has a recognized potential for misuse; a clinician should advise on appropriate use.
Frequently asked questions
When is cyclizine taken for travel sickness?+
The NHS directs taking it about 1 to 2 hours before travel, with further doses during a longer journey if needed. We don't give dosing instructions — follow the current product leaflet or ask your pharmacist.
How quickly does cyclizine work?+
Per the UK SmPC, effects develop within about 30 minutes, are maximal within 1 to 2 hours, and last roughly 4 to 6 hours. The NHS gives similar figures. Individual experience can vary.
Is cyclizine available in the US?+
Not generally — the cyclizine brand Marezine has been discontinued in the US, and OTC motion-sickness products there typically use meclizine or dimenhydrinate. In the UK it is available from a pharmacy and on prescription.
Does cyclizine cause drowsiness?+
Yes — it is a sedating antihistamine and commonly causes drowsiness. The NHS advises not driving, cycling, or operating heavy machinery if it makes you drowsy or dizzy, and avoiding alcohol.
Sources
Related
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.