A beta-blocker eye drop for glaucoma
Timolol
A beta-blocker eye drop that lowers the pressure inside the eye in glaucoma; even as a drop it can cause beta-blocker effects on breathing and the heart.
What is Timolol?
Timolol is a beta-blocker eye drop used to lower the pressure inside the eye in glaucoma and ocular hypertension. Although it is only a drop, enough can be absorbed to cause beta-blocker effects on breathing and the heart, so it is avoided in asthma and certain heart conditions. Pressing on the inner corner of the eye after using it reduces this absorption.
Education and reference only. This is a plain-language guide to Timolol — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Timolol is a beta-blocker used as eye drops to lower the pressure inside the eye in glaucoma and ocular hypertension. It is a long-standing, widely used treatment, available on its own and combined with other glaucoma medicines in a single drop. Lowering eye pressure helps protect the optic nerve and preserve sight over time. Although it is applied only to the eye, a meaningful amount can be absorbed into the rest of the body, so it carries some of the same cautions as beta-blocker tablets.
How it works
Timolol blocks beta receptors in the eye, which reduces the amount of fluid (aqueous humour) the eye produces. With less fluid being made, the pressure inside the eye falls, which helps protect the optic nerve from damage in glaucoma. Because the drop can be absorbed through the eye's surface and the tear duct into the bloodstream, it can also block beta receptors in the lungs and heart, which is why it can affect breathing and heart rate even as an eye drop.
Company & origin
Originated / developed by: Developed by Merck (MSD)..
Timolol eye drops were introduced in the late 1970s and became a long-standing first-line treatment for raised eye pressure.
What it treats
Conditions Timolol is used for
Practical use
How to take Timolol
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Use the drops regularly as prescribed to keep eye pressure controlled.
- After instilling a drop, gently close the eye and press on the inner corner near the nose for a short while to reduce absorption into the body.
- If you use more than one eye drop, leave a few minutes between them so each has time to work.
- Be aware that even as a drop it can affect breathing and the heart; report new wheeze, breathlessness or a slow heartbeat.
- Do not stop using it without advice, as eye pressure can rise again.
- If you wear contact lenses, follow your optician's advice, as some drops require lenses to be removed first.
Weighing it up
Advantages & disadvantages of Timolol
Advantages
- Effective and long-established at lowering eye pressure in glaucoma.
- Usually used once or twice a day and generally well tolerated locally.
- Available combined with other glaucoma medicines in a single drop for convenience.
Disadvantages
- Can cause beta-blocker effects on breathing and the heart even though it is only a drop.
- Not suitable for people with asthma or certain heart conditions.
- May cause local stinging, dryness or blurred vision after instilling.
- Needs correct technique (and corner pressure) to limit absorption and to ensure the drop reaches the eye.
Practical use
Good to know
After putting the drop in, gently closing the eye and pressing on the inner corner near the nose for a short while (nasolacrimal occlusion) reduces how much drains into the body and lowers the chance of beta-blocker side effects. Even as a drop it can cause systemic beta-blocker effects — it can trigger or worsen asthma and breathing problems and can slow the heart — so it is avoided in asthma and certain heart conditions. If you use more than one type of eye drop, leave a few minutes between them so they are not washed out. It is taken regularly to keep eye pressure controlled, and should not be stopped without advice, as pressure can rise again.
Who should not take it / use with caution
- People with asthma or a history of significant airways disease, where even the absorbed drop can trigger dangerous breathing problems.
- People with certain heart conditions, such as a slow heart rate, some heart-block problems or uncontrolled heart failure.
- Used with caution in diabetes (it can mask some warning signs of low blood sugar), other breathing problems, and in pregnancy and breastfeeding.
Monitoring
- Regular eye-pressure checks and optic-nerve and visual-field assessment by the eye team.
- Watching for breathing problems and a slow heart rate, especially when first starting.
- Reviewing inhaler use and heart medicines for any interaction.
Side effects
- Local stinging, burning, dryness, redness or blurred vision after instilling the drop.
- Systemic beta-blocker effects: a slowed heart rate, low blood pressure, or breathing problems including wheeze.
- Tiredness, dizziness and, occasionally, low mood or vivid dreams.
- Worsening of asthma in susceptible people, which can be serious.
Key interactions
- Beta-blocker tablets and some heart-rate-slowing medicines (such as certain calcium-channel blockers) — added slowing of the heart and lowering of blood pressure.
- Medicines for diabetes, as the absorbed beta-blocker can mask some warning signs of low blood sugar.
- Tell your prescriber and pharmacist about all your medicines, including other eye drops.
Available as: Available as eye drops, including single-dose units and combined drops with other glaucoma medicines.
Answers
Timolol: frequently asked questions
How can I reduce side effects from timolol eye drops?
After putting the drop in, gently close the eye and press on the inner corner near the nose for a short while. This reduces how much drains into the body and lowers the chance of beta-blocker side effects.
Can I use timolol if I have asthma?
Generally no. Even as a drop, enough can be absorbed to trigger or worsen asthma, so it is avoided in asthma and significant airways disease.
I use more than one eye drop — does the order matter?
Leave a few minutes between different drops so one does not wash the other out. Your eye team can advise on timing.
Can timolol drops affect my heart?
Yes. The absorbed beta-blocker can slow the heart and lower blood pressure, so it is used with caution in certain heart conditions. Report a slow heartbeat or breathlessness.
Can I stop using the drops if my eyes feel fine?
No, not without advice. Glaucoma usually has no symptoms, and stopping can let eye pressure rise and damage sight.
The wider class
About Glaucoma eye drops
Timolol belongs to the glaucoma eye drops class. For how the class as a whole works, its shared safety principles and monitoring, see the full guide.
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Authoritative sources
- BNF
- NICE CKS
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