What types of glaucoma drops are there?
The name on the bottle
There are various kinds of pressure-lowering eye drops used in the treatment of glaucoma. All the drugs used in them have standard pharmaceutical names, which are not trade names. If your drops are only labelled with the names of the drug or drugs they contain, they are said to be ‘generic’. However, many drops are better known by their trade name, chosen by the company that developed the drug and have the patent. There are certain glaucoma drops where use in children is restricted (please see our booklet Glaucoma in Babies and Children).
Generic substitutes for branded drops
As patents on glaucoma drops expire, more patients are receiving a generic version of their prescription in place of a branded one. The active ingredient(s) are the same and at the same concentration. Other constituents may vary slightly but the eye drops are essentially similar. The bottle and packaging are likely to be different, and may vary from one prescription to another.
Most people have no trouble with generic drops, but there can be some issues. For example, the design of the bottle might not fit your compliance aid or you may not be able to squeeze the new bottle if the plastic is too hard. Very rarely, the slightly different formulation may not suit you. If you experience any difficulty you should discuss it with your eye specialist, GP or pharmacist. Alternatively, the Glaucoma UK helpline will be able to help and advise.
Combination drops
If you need two different types of medication, using a combination drop can have advantages over using two separate drops. It saves both time and having to keep two different bottles. It also means that you deliver less preservative into your eye, which may reduce the possibility of developing an allergic reaction to the preservatives. For patients who pay for their prescriptions, only one prescription charge is levied for a combination drop.
Different categories of drops
The drugs used in eye drops to treat glaucoma fall into several categories, according to the way in which they work.
Alpha agonists (apraclonidine and brimonidine)
These act to reduce the production of fluid in the eye and possibly to improve the flow of fluid out of the eye. They are usually used two or three times a day. Brimonidine is licenced for the long-term treatment of glaucoma but apraclonidine is for short-term use following, or to delay, laser treatment. Possible side effects include a dry mouth, tiredness and general weakness. Very occasionally people may develop a severe allergic reaction to these drops. If this happens, the eye becomes increasingly red, sore and sticky. It can take several months for this to happen, but if it does, you should consult your ophthalmologist or general practitioner without delay.
Beta blockers (betaxolol, carteolol, levobunolol and timolol)
The action of these drops is to reduce the production of fluid in the eye. They are used once in the morning or twice a day, as advised by your ophthalmologist. They are not usually prescribed for anyone susceptible to chest or breathing problems. Possible side effects include a slow pulse, dizziness and tiredness. In some people, these drops may cause depression, loss of libido or impotence. However, most people have no problems with them.
Carbonic anhydrase inhibitors (brinzolamide and dorzolamide)
The action of these drugs is to reduce production of fluid in the eye. These drops are used two or three times a day on their own, or twice a day if with another drop. Possible side effects include redness of the eye, crusty eyelashes, fatigue and a bitter taste in the mouth.
Cholinergic agonist (pilocarpine)
These act to improve the flow of fluid out of the eye through its usual route and the drops are used three or four times a day.
Prostaglandin/prostamide analogues (bimatoprost, latanoprost, tafluprost and travoprost)
Their action is to improve the flow of fluid out of the eye through a different route from the usual one. The drops are used once a day, usually at night. Possible side effects include a pink eye which usually improves over a period of time. The iris may darken in colour (more commonly in those with green or hazel eyes and less commonly in blue eyes). Eyelashes may grow longer and darker and in a small percentage of patients, the skin around the orbit of the eye may darken.
