Tavegil (clemastine)

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How does it work?

Tavegil tablets contain the active ingredient clemastine, which is a type of medicine called a 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, pet fur, dust mites), the mast cells are stimulated by the allergen and 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 hayfever, this causes inflammation of the nose, eyes, skin or airways and results in itchy watery eyes, a runny nose, sneezing and nasal congestion. Histamine is also responsible for the symptoms of allergic and itchy rashes, and allergic reactions to foods, medicines or insect bites. It can also cause more severe allergic reactions such as angioneurotic oedema, which involves severe swelling of the eyes, lips, tongue or throat.

Clemastine works by blocking histamine H1 receptors. It doesn't 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 the symptoms of allergies.

Clemastine is called a sedating antihistamine because it enters the brain in significant quantities and causes drowsiness.

What is it used for?

- Allergic conditions such as hayfever, nettle rash and reactions to insect bites.

Warning!

- This medicine may cause drowsiness, blurred vision or dizziness. If affected do not drive or operate machinery. Children should avoid potentially hazardous activities such as riding bikes or climbing trees if affected. Alcohol should be avoided.
- If you are due to have any skin prick tests to diagnose allergies you should stop taking your antihistamines at least 48 hours before the tests. This is because antihistamines can prevent or lessen the skin reactions that indicate an allergy, and so can make the test results unreliable.
- If symptoms persist despite treatment, seek medical advice from your doctor or pharmacist.

Use with caution in

- Elderly people
- Liver disease
- Kidney disease
- Epilepsy
- Glaucoma
- Enlarged prostate gland
- Difficulty in passing urine (urinary retention)
- Obstruction of the gut.

Not to be used in

- Children under one year of age
- Hereditary blood disorders called porphyrias.

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.

- The safety of this medicine during pregnancy has not been established. It should be avoided during pregnancy, unless the potential benefits to the mother outweigh any possible risk to the developing baby. This is particularly important during the first and third trimesters. As with all medicines, seek medical advice from your doctor before using this medicine if you are pregnant.
- This medicine passes into breast milk and could be harmful to a nursing baby. It should not be taken by breastfeeding mothers unless considered essential by your doctor. Seek further medical advice from your doctor.

Label warnings

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

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