Latanoprost eye drops (Xalatan): uses, side effects and cautions

Latanoprost treats high pressure in the eye, which is usually caused by fluid building up in the front of the eye and which, untreated, can damage the optic nerve and cause loss of vision. It is a core treatment in glaucoma and in ocular hypertension. It comes as eye drops, either in bottles containing a preservative or in preservative-free single-dose droppers. Some people are given a combination drop containing latanoprost and timolol, a beta blocker.

Latanoprost belongs to the prostaglandin analogue family. It increases the natural drainage of fluid from inside the eye into the bloodstream, which lowers pressure and helps stop vision from getting worse. The NHS says pressure begins to drop 3 to 4 hours after the drops, full effect arrives after 8 to 12 hours, and the lower pressure lasts for at least 24 hours. That is why one daily drop is enough.

Related drops include bimatoprost, tafluprost and travoprost, and the latanoprost and timolol combinations sold as Xalacom and Fixapost. Laser treatment and surgery are other options in glaucoma; they cannot reverse lost sight but can help stop further loss.

The NHS gives the usual adult and child dose as 1 drop in the affected eye or eyes once a day, and says the evening is best because latanoprost works better then. Use it every day. Wash your hands, remove contact lenses first and wait 15 minutes before putting them back. Pull the lower eyelid gently down, tilt your head back, squeeze one drop in, then close the eye and press a finger gently over the inner corner for about a minute to keep the drop in. Wipe away any excess.

If you use other eye drops, wait at least 5 minutes between them, because a second drop can wash out the latanoprost. A bottle should be used within its expiry date and within 4 weeks of opening, while single-dose droppers should be discarded after use and, once their sachet is opened, used within 10 days. Writing the opening date on the box helps.

If you forget, skip the missed drop and carry on the next day as usual, and never use two doses at once. Too many drops can irritate, water and redden the eye; rinse out any excess with water and wait until the next due dose. If you swallow latanoprost and feel unwell, call NHS 111.

Most people use latanoprost for life, though a doctor may add or change treatment if pressure is not well controlled. Regular check-ups are part of the treatment, since the drops control pressure but sight loss can still progress. Pressure may rise if you stop, so speak to your doctor or pharmacist first.

Common effects, affecting up to 1 in 10 people, include a change in eye colour, red and itchy eyelids, eye irritation and pain, an inflamed eyelid, conjunctivitis, longer and thicker eyelashes and sensitivity to light. A colour change, when it happens, usually starts within 8 months, can be permanent and may be more obvious if only one eye is treated, so discuss concerns before starting. Eyelashes usually return to normal after stopping. A warm clean flannel on the eyelids, cleaning with cooled boiled water or sunglasses can ease some symptoms.

Serious effects are rare, around 1 in 1,000. Stop using the drops and call a doctor or 111 if you have a fast heart rate. Call 999 or go to A&E for chest pain or wheezing with difficulty breathing. Swelling of the lips, mouth, throat or tongue needs 999. Suspected side effects can be reported through the Yellow Card scheme.

Most adults and children, including babies, can use latanoprost. Tell your doctor first if you have ever reacted to it or another medicine, are about to have or have had eye surgery including cataract surgery, have eye pain, irritation, inflammation, blurred vision or dry eyes, have severe or uncontrolled asthma, wear contact lenses or have ever had herpes simplex infection of the eye.

The NHS asks you to mention other prostaglandin-type drops such as tafluprost, travoprost or bimatoprost, because using two together can raise eye pressure. Alcohol and food are unrestricted and contraception is unaffected.

Latanoprost can be used in pregnancy and breastfeeding, because very little reaches the blood and treating glaucoma is essential, and it is not thought to pass into milk. There is no evidence of reduced fertility.

Blurred vision for a short while after the drops means you should not drive, cycle or use tools until you see clearly. Many people with glaucoma can keep driving, provided eyesight meets the DVLA standards. Chest pain and palpitations are rare effects, but the NHS says there are no reports of it worsening existing atrial fibrillation.