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Alfresed, Itzenal

Alimemazine is used to keep young children calm before an operation, and to ease allergic skin reactions.

It will make you feel sleepy which can affect your ability to drive. If you feel drowsy or sleepy, do not drive and do not use tools or machines.

Continue reading below

About alimemazine

Type of medicine

A phenothiazine antihistamine

Used for

Some allergic skin conditions, and as a sedative for young children before an operation

Also called

Trimeprazine (in US); Alfresed®, Itzenal®

Available as

Tablets and oral liquid medicine

Alimemazine is used to relieve lumpy and itchy allergic skin reactions called hives (urticaria). It is also used before surgical procedures to help keep young children calm.

Alimemazine, an antihistamine, works by blocking a substance called histamine in the body. In some people, an excess of histamine is produced by exposure to substances such as pollen, pet fur, house dust or insect bites, and this causes allergic skin reactions. By blocking histamine, alimemazine eases the itchiness and lumpiness of these reactions.

When alimemazine is prescribed for a young child who is about to have an operation, it produces a sedative effect which helps the child feel relaxed. Alimemazine is not suitable for children under 2 years of age.

Before taking alimemazine

Some medicines are not suitable for people with certain conditions, and sometimes a medicine may only be used if extra care is taken. For these reasons, before you start taking alimemazine it is important that your doctor or pharmacist knows:

  • If you are pregnant, trying for a baby or breastfeeding.

  • If you have a heart condition or blood vessel disease.

  • If you have liver, kidney, or prostate problems.

  • If you have any difficulties passing urine or if you have been constipated for some time.

  • If you have breathing problems.

  • If you have any of the following: epilepsy, Parkinson's disease, depression, increased pressure in your eyes (glaucoma), or a condition called myasthenia gravis which causes muscle weakness.

  • If you have ever had yellowing of your skin or of the whites of your eyes (jaundice) or a blood disorder.

  • If you have low levels of thyroid hormone (hypothyroidism).

  • If you have a tumour on your adrenal gland (phaeochromocytoma).

  • If you have a rare inherited blood disorder called porphyria.

  • If you are taking or using any other medicines. This includes any medicines you are taking which are available to buy without a prescription, as well as herbal and complementary medicines.

  • If you have ever had an allergic reaction to another antihistamine, or to any other medicine.

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How to take alimemazine

  • Before you start this treatment, read the manufacturer's printed information leaflet from inside your pack. The manufacturer's leaflet will give you more information about alimemazine and a full list of side-effects which you may experience from taking it.

  • Take alimemazine exactly as your doctor tells you to. This information will be printed on the label of the pack you have been supplied with to remind you. The usual recommended doses for allergic skin reactions are:

    • For adults and children aged 12 years or over: 10 mg taken 2 or 3 times a day (it may be less than this if you are over 65 years of age).

    • For children 5-11 years of age: 5 mg taken 3 or 4 times daily.

    • For children 2-4 years of age: 2.5 mg taken 3 or 4 times daily.

  • If you are giving alimemazine liquid medicine to a child, make sure you follow the dosing instructions on the bottle carefully so that you measure out the correct dose.

  • You can take alimemazine before or after meals. Some people find it helps to swallow the tablets with a drink of water.

  • If you forget to take a dose, don't worry, just take the next dose when it is due and then continue as before. Do not take two doses together to make up for a forgotten dose.

Getting the most from your treatment

  • Alimemazine causes drowsiness. If you feel drowsy or sleepy, do not drive and do not use tools or machines.

  • Do not drink alcohol while you are on alimemazine as it increases the chance you will feel sleepy.

  • Alimemazine may cause your skin to become more sensitive than normal to sunlight. Use a sunscreen that protects against UVA light and has a sun protection factor (SPF) of at least 15, especially in strong sunlight or until you know how your skin reacts. Do not use sunbeds.

  • If you buy any medicines, check with a pharmacist that they are suitable to take with alimemazine. This is because a number of other medicines can interfere with the way alimemazine works or can increase the risk of side-effects.

  • If you are having an operation or any dental treatment, tell the person carrying out the treatment that you are taking alimemazine.

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Can alimemazine cause problems?

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains some of the most common ones associated with alimemazine, particularly when it is taken over a period of time. You will find a full list in the manufacturer's information leaflet supplied with your medicine. The unwanted effects often improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following continue or become troublesome.


alimemazine side-effects

What can I do if I experience this?

Feeling sleepy or dizzy, blurred vision

If this happens, do not drive and do not use tools or machines. You may feel light-headed, particularly when you first start taking this medicine. Getting up more slowly until you are aware how you react should help

Dry mouth

Try chewing sugar-free gum or sucking sugar-free sweets


Ask your doctor or pharmacist to recommend a suitable painkiller

Stomach upset

Stick to simple meals

Feeling shaky or restless, unusual or uncontrollable muscle movements

Speak with your doctor as soon as possible

Sleeping problems, mood changes, stuffy nose, changes in sexual ability, breast changes or tenderness, menstrual problems, fast heartbeat, constipation, difficulty passing urine, rash

Discuss these with your doctor if any become troublesome

If you experience any other symptoms which you think may be due to this medicine, speak with your doctor or pharmacist.

How to store alimemazine

  • Keep all medicines out of the reach and sight of children.

  • Store in a cool, dry place, away from direct heat and light.

Important information about all medicines

Important information about all medicines

If you buy any medicines check with a pharmacist that they are safe to take with your other medicines.

Never take more than the prescribed dose. If you suspect that you or someone else might have taken an overdose of this medicine, go to the accident and emergency department of your local hospital. Take the container with you, even if it is empty.

If you are having an operation or any dental treatment, tell the person carrying out the treatment which medicines you are taking.

This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.

Do not keep out-of-date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.

If you have any questions about this medicine ask your pharmacist.

Report side effects to a medicine or vaccine

If you experience side effects, you can report them online through the Yellow Card website.

Further reading and references

Article history

The information on this page is written and peer reviewed by qualified clinicians.

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