Alphagan eye drops contain the active ingredient brimonidine, which is a type of medicine called an alpha agonist. It works by stimulating alpha receptors found on blood vessels in the eye.
The pressure within the eyeball is naturally maintained by a continuous flow of liquid called aqueous humour through the eyeball. Aqueous humour is produced by a part of the eye called the ciliary body. It drains out of the eyeball through channels called the trabecular meshwork. If the outflow of aqueous humour is blocked, as in glaucoma, the aqueous humour builds up inside the eye, increasing the pressure within the eyeball. This pressure needs to be reduced, as otherwise it can damage the optic nerve and impair vision as a result.
Brimonidine stimulates alpha receptors found on the blood vessels that supply the ciliary body. This causes the blood vessels to constrict, and reduces the amount of watery fluid that filters out of the blood vessels to form aqueous humour.
Brimonidine therefore works by reducing the inflow of aqueous humour into the eyeball, which decreases the pressure within the eye. It is used to treat conditions where there is raised pressure in the eye, such as glaucoma.
Brimonidine eye drops are used to treat glaucoma in people who cannot use beta-blocker eye drops. They may also be used in conjunction with other types of eye drop, for example beta-blockers or prostglandin analogues, to treat glaucoma in people whose eye pressure has not been lowered sufficiently with one medicine.
Eye drops are used to produce a local effect in the eye, with minimal effect on other parts of the body. You can further minimise the amount of medicine that is absorbed into your bloodstream and increase the local action in the eye by pressing on your tear duct (the corner of the eye closest to the nose) while putting in the eye drops and for a minute after.
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.
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.
Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here does not mean that all people using this medicine will experience that or any side effect.
The side effects listed above may not include all of the side effects reported by the drug's manufacturer.For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.
The brimonidine in these eye drops could be absorbed into the bloodstream in low amounts after application to the eye and it could therefore interact with other medicines that you are taking by mouth, injection, skin patch or suppository. You should tell your doctor or pharmacist what medicines you are already using, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, check with your doctor or pharmacist before starting any new medicines while using this one, to ensure that the combination is safe.
The manufacturer states that these eye drops should not be used by people taking any of the following medicines:
If you are using more than one type of eye drop you should administer them at least five minutes apart, to prevent the second drop washing away the first. Use eye gels or ointments last.
There are currently no other medicines available in the UK that contain brimonidine as the sole active ingredient.
Combigan eye drops contain brimonidine in combination with the beta-blocker medicine timolol.