A sedating antihistamine for nausea and motion sickness
Meclozine
A sedating antihistamine used to prevent and ease nausea, vomiting and travel sickness.
What is Meclozine?
Meclozine is an older, sedating antihistamine used mainly to prevent and ease nausea, vomiting and motion (travel) sickness. It works by calming the parts of the brain and inner-ear balance system that trigger sickness. Because it is sedating, the most common effect is drowsiness, so it can affect driving and is best taken with this in mind. Like other older antihistamines it can cause antimuscarinic effects such as a dry mouth and blurred vision, and is used with care in people with glaucoma or prostate problems. It is taken by mouth, ideally a little before travelling.
Education and reference only. This is a plain-language guide to Meclozine — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Meclozine is a long-established antihistamine of the sedating type, which means it tends to make people feel sleepy. Although antihistamines are best known for allergy, this one is used mainly for its effect on sickness: it helps prevent and treat nausea, vomiting and motion sickness, including the dizziness and queasiness that come with travel. It is taken by mouth as a tablet and works best when taken a little while before a journey rather than after sickness has already set in. It is available both on prescription and, for travel sickness, to buy from pharmacies.
How it works
Feeling sick and vomiting are partly driven by signals from the inner-ear balance system and by a sickness centre in the brain. Meclozine blocks histamine and has some drying (antimuscarinic) action, and together these calm those signals, which reduces nausea and the urge to be sick. Because it dampens down the balance-related signals, it is particularly useful for motion sickness and the dizziness that goes with it. The same calming effect on the brain is why it commonly causes drowsiness. It works best taken in advance, before sickness builds up.
Company & origin
Originated / developed by: Generic (long-established).
An older antihistamine used in the UK to prevent and treat nausea, vomiting and motion sickness.
Practical use
How to take Meclozine
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Take it by mouth, ideally a little while before travelling rather than waiting until you feel sick.
- Be aware it commonly causes drowsiness, so avoid driving or operating machinery until you know how it affects you.
- Avoid alcohol while taking it, as this adds to the drowsiness.
- If you take other sedating medicines, tell your pharmacist or prescriber, as the sleepiness can add up.
- Tell your pharmacist if you have glaucoma, prostate problems or trouble passing urine before using it.
Weighing it up
Advantages & disadvantages of Meclozine
Advantages
- An effective, inexpensive way to prevent and ease nausea, vomiting and motion sickness.
- Taken by mouth and works well when taken before a journey.
- Long-established with decades of experience behind its use.
Disadvantages
- Commonly causes drowsiness, which can affect driving and concentration.
- Can cause antimuscarinic effects such as a dry mouth, blurred vision and constipation.
- Used with caution in people with glaucoma, prostate problems or difficulty passing urine.
Practical use
Good to know
The main thing to know about meclozine is that it makes many people drowsy, so it is sensible to avoid driving, operating machinery or drinking alcohol until you know how it affects you. For travel sickness it works far better taken before you set off rather than once you already feel ill. As an older antihistamine it can cause antimuscarinic effects such as a dry mouth, blurred vision or constipation, and for the same reason it is used with caution in people with glaucoma, an enlarged prostate or difficulty passing urine, where it can make things worse. Older people can be more sensitive to these effects. It can also add to the drowsiness of other sedating medicines, so it helps to tell your pharmacist or prescriber what else you take.
Who should not take it / use with caution
- People who have had a serious allergic reaction to meclozine should not take it.
- It is used with caution in people with glaucoma, an enlarged prostate or difficulty passing urine, as it can make these worse.
- It is used with care in older people, who can be more sensitive to drowsiness and antimuscarinic effects.
Monitoring
- Checking how well it controls nausea or travel sickness.
- Watching for troublesome drowsiness or antimuscarinic effects, especially in older people.
- Reviewing whether it is still needed for longer-term sickness.
Side effects
- Drowsiness, which is the most common effect.
- A dry mouth, blurred vision or constipation from its antimuscarinic action.
- Less commonly, dizziness, headache or difficulty passing urine.
Key interactions
- Alcohol and other sedating medicines, such as sleeping tablets or strong painkillers, add to the drowsiness.
- Other medicines with antimuscarinic (drying) effects can combine with it to cause more dry mouth, blurred vision or constipation.
- Tell your pharmacist or prescriber about all your medicines so these effects can be considered.
Available as: Tablets taken by mouth.
Answers
Meclozine: frequently asked questions
What is meclozine used for?
It is a sedating antihistamine used mainly to prevent and ease nausea, vomiting and motion (travel) sickness.
Will it make me drowsy?
Yes, drowsiness is the most common effect, so avoid driving or operating machinery and avoid alcohol until you know how it affects you.
When should I take it for travel sickness?
It works best taken a little while before you travel, rather than waiting until you already feel sick.
Can anyone take it?
It is used with caution in people with glaucoma, prostate problems or difficulty passing urine, so tell your pharmacist about these before using it.
Why does it dry my mouth?
Like other older antihistamines it has a drying (antimuscarinic) action, which can cause a dry mouth, blurred vision or constipation.
The wider class
About Sedating antihistamine (for nausea and motion sickness)
Meclozine belongs to the sedating antihistamine (for nausea and motion sickness) class. For how the class as a whole works, its shared safety principles and monitoring, see the full guide.
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Authoritative sources
- BNF
- NICE CKS
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