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Understanding Your Glaucoma Medications: Eye drops
When it comes to managing glaucoma, reducing eye pressure is key to slowing the progression of the condition. There are several treatment options available, including eye drops, tablets, and even some newer treatments. Here's a guide to help you understand the different medications used in glaucoma treatment and what to expect from each.
An expert guide:
How to Apply Eye Drops
Step 1: Shake the bottle well.
Step 2: Tilt your head back, pull down your lower eyelid with one hand, and hold the bottle with your other hand resting on your forehead or nose.
Step 3: Place a drop into your eye.
Step 4: If you're not sure the drop went in, it's okay to try again.
Step 5: After applying the drop, close your eyes and press gently between your lower eyelid and nose for 1-2 minutes. This helps prevent the medication from draining into your nose and throat, which can reduce side effects.
Step 6: Wait 5 minutes between applying different drops.
Some people struggle to administer their own eye drops. Dispensers like the one below can sometimes help.
Eye Drops: Your First Line of Defence
Most patients with glaucoma will be treated with eye drops. With many different types available, it can be a bit confusing to know which one is right for you. Each type of drop works to lower eye pressure, but the effectiveness and side effects can vary from person to person. Some drops are also available in preservative-free formulations, which may be helpful if you have dry eyes or wear contact lenses.
Prostaglandin Analogues
Prostaglandin analogues such as Latanoprost (Xalatan™), Travoprost (Travatan™), and Bimatoprost (Lumigan™), are highly effective at reducing eye pressure, often by around 30%. These drops are frequently the first line of treatment. They work by increasing fluid outflow from the eye.
Common side effects include mild stinging, eye redness, and increased eyelash growth. In some cases, they can cause changes in eye colour and fat loss around the eyes.
Bimatoprost may be slightly more effective at reducing your eye pressure but comes with a higher chance of side effects.
Beta-blockers
Beta-blockers like Timolol (Timoptol™/Tiopex™) and Betaxolol (Betoptic™) reduce fluid production in the eye and can also increase fluid outflow.
They are slightly less effective than prostaglandin analogues but have fewer aesthetic side effects.
Cholinergic agonists
Cholinergic agonists, like Pilocarpine, help by constricting the pupil and increasing fluid outflow.
They’re usually used in emergencies and can cause headaches and reduced night vision.
Carbonic anhydrase inhibitors
Carbonic anhydrase inhibitors include drops like Dorzolamide (Trusopt™) and Brinzolamide (Azopt™). These medications reduce fluid production in the eye and can lower pressure by around 20%.
Side effects may include stinging, redness, and a metallic taste. In rare cases, they can affect your blood cells.
Alpha-agonists
Alpha-agonists, such as Brimonidine (Alphagan™) and Apraclonidine (Iopidine™), lower fluid production and increase fluid outflow. They can cause redness, itching, and dry mouth.
Some patients may develop conjunctivitis (a bright red, itchy, watery eye), which means the drops need to be stopped. It's also important to avoid using these if you're on certain antidepressants like amitriptyline.
New options
Newer options include nitric oxide donating prostaglandins such as Latanoprostene bunod (Vyzultar™), which are similar to prostaglandin analogues but also increase fluid outflow through the eye's internal drainage system.
Rho-kinase/ norepinephrine transport inhibitors, like Netarsudil (Rhokiinsa™) or the combination of Latanoprost and Netarsudil (Roclanda™), are new drugs that work by several mechanisms to reduce eye pressure. Roclanda became available in the UK in 2024.
These newer drugs may cause side effects like eye redness and increased watering.
Understanding your Glaucoma Medications: Tablets
If you’re considering any tablet-based treatments, it’s crucial to have a detailed discussion with your eye specialist to ensure it’s the best option for your specific situation and health conditions.
Acetazolamide Tablets (Diamox™)
Acetazolamide (Diamox™) is a carbonic anhydrase inhibitor, similar to certain eye drops used in glaucoma treatment. It's very effective at reducing eye pressure, but because of its potential side effects, it’s typically used only for short periods, such as when your eye pressure is particularly high or while you're waiting for surgery. Acetazolamide is available in both regular and slow-release (SR) formulations, and there's little difference in their effectiveness, so either can be used depending on your needs.
Side Effects of Acetazolamide
While Acetazolamide is effective, it can cause some side effects. Commonly, you might experience dizziness, tiredness, tingling in the fingers, and increased urination. In rare cases, it may lead to changes in your blood cells or worsen kidney stones. It’s particularly important to avoid or use a lower dose of Acetazolamide if you have sickle cell anaemia, kidney stones, or severe kidney or liver disease. The medication can also reduce potassium levels, so you might be advised to consume high-potassium foods or drinks, such as a banana, a serving of spinach, or a glass of tomato juice, with each tablet. In some cases, your doctor may prescribe Sando-K potassium supplement tablets to take alongside Acetazolamide.
Nicotinamide
There is ongoing research investigating whether oral nicotinamide tablets - at a dose of 1.5g daily for 6 weeks followed by 1.5g twice daily - may slow glaucoma progression. Nicotinamide does not reduce eye pressure but may slow glaucoma progression via a different mechanism: improving mitochondrial function. Rarely, nicotinamide may cause serious liver damage, so patients must check their liver function blood tests regularly while treatment continues. As trials on nicotinamide are ongoing, it is not currently recommended as a treatment by most glaucoma specialists.
Side Effects of Nicotinamide
Nicotinamide may not be suitable for everyone. It is contraindicated if you have impaired liver function, are pregnant, have a history of cancer, or are taking certain medications such as doxycycline, isoniazid, pyrazinamide, or carbamazepine. Nicotinamide can rarely cause life-threatening liver damage. It’s important to consult your doctor before considering nicotinamide as part of your treatment plan.