Type of medicine Antihistamine
Used for Allergic conditions including rhinitis (inflammation of the lining of the nose) and conjunctivitis (inflammation, itching and soreness of the eye)
Also called Zaditen
Available as Tablets
Oral liquid
Eye drops

Exposure to pollen, pet fur, house dust, an insect bite or another trigger, can cause the body to produce a chemical called histamine. The release of histamine causes allergic symptoms that can include sneezing, itchy or watery eyes, a running or blocked nose and sometimes skin reactions such as itching, swelling and rashes. Ketotifen stops the effects of histamine and helps to relieve these symptoms.

Why is this drug prescribed?

Zaditen tablets and elixir contain the active ingredient ketotifen hydrogen fumarate, which is a type of drug called an antihistamine. 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, the mast cells stimulated by the allergen release their stores of histamine. The released histamine then binds to its 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. For example, in hayfever, histamine causes inflammation of the nose, resulting in a runny nose, sneezing and nasal congestion. Ketotifen is thought to work in a number of ways. It prevents the release of histamine from mast cells and also blocks H1 receptors, so that any histamine that is released is prevented from having an effect. By blocking the actions of histamine, ketotifen helps prevent your body from reacting to allergens that would normally cause your allergic symptoms, eg hayfever.

Treatments

* Allergic conditions such as allergic rhinitis or allergic conjunctivitis

What side effects can this drug cause?

* Drowsiness * Dry mouth * Dizziness * Weight gain * Irritability * Difficulty sleeping * Nervousness * Excitation * Bladder inflammation, commonly caused by infection * Inflammation of the liver * Convulsions * Isolated severe skin reactions