Vallergan

How does it work?

Vallergan tablets, syrup and forte syrup all contain the active ingredient alimemazine (previously known as trimeprazine in the UK). Alimemazine is derived from a group of medicines called phenothiazines, and is a type of medicine called a non-sedating antihistamine. It works by preventing the actions of histamine.

Histamine is a substance produced by the body as part of its defence mechanisms. It is stored in cells called mast cells, in almost all tissues of the body. When the body reacts to a foreign substance (known as an allergen, eg flower pollen), the mast cells stimulated by the allergen release their stores of histamine.

The released histamine then binds to its receptors (H1 receptors), causing a chain reaction that results in allergic symptoms. It causes an increase in blood flow to the area of the allergy, and the release of other chemicals that add to the allergic response.

All this results in the symptoms of an allergic reaction. In skin allergies, histamine causes inflammation of the skin and results in an itchy rash, swelling and hives, called nettle rash or urticaria.

Alimemazine works by blocking histamine H1 receptors. It does not prevent the actual release of histamine from mast cells, but prevents it binding to its receptors. This in turn prevents the release of other allergy chemicals and increased blood supply to the area, and provides relief from itching and nettle rash.

Alimemazine is called a sedating antihistamine because it enters the brain in significant quantities and causes drowsiness. As a result, it can be particularly useful for itching that is worse at night. This is often the case in children, who notice itching less during the day when they are active, but are bothered by it at night when they are still and have nothing else to focus on.

Alimemazine is also used as a pre-med in children to produce sleepiness before operations. It is given one to two hours before the anaesthetic.

What is it used for?

Allergic itchy skin rash (urticaria or nettle rash)

Itching (pruritis)

Pre-med to cause drowsiness before an anaesthetic in children aged two to seven years

Warning!

This medicine may cause drowsiness. If affected do not drive or operate machinery. Children should take care performing potentially hazardous activities such as climbing trees and riding bikes. Alcohol should be avoided.

This medicine may cause dizziness and light-headedness when moving from a lying down or sitting position to sitting or standing. Take care when getting up, particularly if you wake up in the night, until you know how this medicine affects you. If you feel dizzy or light-headed at any time during treatment, sit or lie down until the symptoms pass.

If you are taking high doses of this medicine you should avoid exposing your skin to direct sunlight, as this medicine can increase the sensitivity of your skin to the sun and might make it more likely to burn.

High doses of this medicine can sometimes cause a decrease in the normal amounts of white blood cells in the blood. For this reason, you should consult your doctor if you get a high temperature (fever), sore throat or other signs of infection while taking this medicine. Your doctor may want to take a blood test to check your blood cells.

Consult your doctor if you experience yellowing of the eyes or skin, or unusually dark urine or pale stools while taking this medicine, as these may be signs of jaundice. Your doctor may ask you to stop taking this medicine if you do develop jaundice.

Use with caution in

Elderly people (particularly in very hot or very cold weather)

Constipation

Difficulty passing urine

Heart disease

Low volume of circulating blood (hypovolaemia), eg due to dehydration or high-dose diuretic treatment

Low blood potassium levels (hypokalaemia)

Not to be used in

Children under 2 years of age

Decreased kidney function

Decreased liver function

Epilepsy

Parkinson's disease

Underactive thyroid gland

Tumour of the adrenal gland (phaeochromocytoma)

Abnormal muscle weakness

Enlarged prostate gland

History of closed angle glaucoma

Breastfeeding

Allergy to phenothiazine medicines, eg chlorpromazine, prochlorperazine.

This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy. If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.

Pregnancy and Breastfeeding

Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.

This medicine is not recommended for use in pregnancy unless considered essential by your doctor. Seek medical advice from your doctor.

This medicine passes into breast milk. The manufacturer states that mothers who need to take this medicine should not breastfeed during treatment. Seek medical advice from your doctor.

Label warnings

This medication may cause drowsiness. If affected do not drive or operate machinery. Avoid alcoholic drink.

Go To Next Page>>
The documents contained in this web site are presented for information purposes only. The material is in no way intended to replace professional medical care or attention by a qualified practitioner. The materials in this web site cannot and should not be used as a basis for diagnosis or choice of treatment. Conditions for use



© Copyright 1998 - 2004 NetDoctor.co.uk - All rights reserved