Timolol eye drops: uses, side effects and cautions

Timolol is a beta blocker, the same broad class of medicine as tablets used for blood pressure and heart conditions, but here it is made as an eye drop. It lowers pressure inside the eye, which is often raised in glaucoma. You may need it in one or both eyes. The NHS says timolol is often combined with other medicines in a single eye drop to treat high eye pressure, so check the label to see what your bottle contains.

Wash your hands first. Drops usually come in a small squeezable bottle; some are multi-use and others single-use. After instilling the drop, close the eye and gently press a finger into the inner corner by the nose for 2 minutes. This helps keep the drop on the eye and reduces how much drains into the bloodstream. Your prescriber says how many drops to use each day and for how long.

Do not use the bottle if the dropper tip has touched your fingers, eye or the skin around the eye, because it can cause infection; ask your doctor for a replacement.

If you forget, use the drop when you remember, unless it is nearly time for the next dose, in which case skip the missed one. Never use two doses to make up. The NHS warns that using too many timolol drops can be dangerous, and advises calling NHS 111 if you have used more than the prescribed amount or swallowed any drops. If you are sent to A&E, do not drive.

Possible effects in or around the eye include blurred vision, burning, stinging, itching and redness, and there may be headache, nausea and vomiting. If vision is blurred or the eye is symptomatic, do not drive, cycle or use machinery until it clears. Because some of the drug reaches the blood, tummy ache, pins and needles and sleep problems can occur, but they are not common.

The NHS lists more serious but mostly rare effects: allergic reaction with a swollen throat or tongue, a raised itchy rash and difficulty breathing; eye pain, dryness, inflammation or blurred or double vision that does not improve, which may signal a serious eye problem such as infection; chest pain or a slow, fast or irregular heartbeat; and paralysis, difficulty speaking or loss of consciousness, which may be a stroke. Call 999 if you suspect anaphylaxis, a serious heart problem or a stroke, and NHS 111 for other serious effects.

Most adults can use timolol drops, and they are sometimes prescribed for children. They may not be suitable if you have had an allergic reaction or serious side effect from timolol, other beta blockers or the other ingredients; if you have a breathing problem such as asthma or COPD; if you have a heart condition such as a slow or irregular heartbeat or heart failure; or if you are having an operation. Tell your doctor about any other medical conditions before starting.

Beta blockers can narrow the airways in sensitive people, which is why a drop meant for the eye needs a careful history of breathing and heart problems.

The NHS says these may not mix well with timolol eye drops: other beta blockers taken as tablets or used as eye drops, medicines for high blood pressure such as nifedipine and clonidine, any medicine for diabetes, digoxin for certain heart conditions, and adrenaline-type medicines used for severe allergic reactions. Tell your doctor about all other medicines, herbal remedies, vitamins and supplements. You can eat and drink normally.

Tell your doctor if you are pregnant or become pregnant while using timolol drops. They can be used during pregnancy if needed, and your doctor will weigh up the risks and benefits. They can be used while breastfeeding too, because small amounts pass into milk but are unlikely to cause side effects in the baby. Speak to a healthcare professional or call 111 if you have concerns about your baby. Suspected side effects can be reported through the Yellow Card scheme.