Health Centres - Zaditen eye drops
How does it work?
Zaditen eye drops contain the active ingredient ketotifen hydrogen fumarate, which is a type of medicine called an 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 (H-1 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 eye allergies, such as seasonal allergic conjunctivitis, histamine causes inflammation of the eyes, making them red, itchy and watery.
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 in the eye, ketotifen eye drops help prevent your eyes from reacting to allergens that would normally cause your eye allergy.
What is it used for?
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Seasonal allergic conjunctivitis
Warning!
- This medicine is not to be taken by mouth.
- These eye drops contain the preservative benzalkonium chloride, which can be absorbed by soft contact lenses. If you wear soft contact lenses, you should remove them before putting in these eye drops. You can put the contact lenses back in 15 minutes after using the drops.
- When using the eye drops you should take care to not touch the dropper tip to any surface, or to your eye, in order to avoid contaminating the eye drops.
- The eye drops may cause your vision to blur temporarily after you have applied them into your eye. Do not drive or operate machinery until this has worn off.
- Zaditen eye drops are sterile until opened. Any remaining medicine should be carefully disposed of four weeks after the first opening, as it is likely to be contaminated. You may find it helpful to write the date of first opening on the packet.
Not to be used in
- Children under three years of age
- Known sensitivity or allergy to any ingredient
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.
Pregnancy and Breastfeeding
Certain medicines should not be used during pregnancy or breastfeeding.

