Zaditen tablets and elixir contain the active ingredient ketotifen hydrogen fumarate, which is a type of medicine called a sedating 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 (known as an allergen, eg house dust mites, pet fur), 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. For example, in hay fever, 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.
Ketotifen is called a sedating antihistamine because it enters the brain in significant quantities and causes drowsiness.
Zaditen tablets and elixir should be taken with or after food. Adults should take one Zaditen tablet twice a day, OR one 5ml spoonful Zaditen elixir twice a day, when needed to relieve symptoms. If this doesn't relieve your symptoms you can increase the dose to two tablets OR two 5ml spoonfuls taken twice a day. Children aged three years and over should be given one Zaditen tablet twice a day, OR one 5ml spoonful Zaditen elixir twice a day, when needed to relieve symptoms. Do not exceed this dose. People who are usually very susceptible to sedating effects of medicines should start by taking half to one Zaditen tablet, OR half to one 5ml spoonful Zaditen elixir, at night for the first few days. You can continue to take this medicine to relieve your symptoms for as long as you are exposed to the allergen, for example throughout the pollen season. Follow the instructions given by your doctor. If your symptoms don't improve despite taking this medicine, seek medical advice from your doctor or pharmacist.