A common prostate and ED medicine is linked to higher glaucoma risk
What happened
A large study has linked long-term use of the medicine tadalafil to a higher chance of developing glaucoma, an eye condition that can steal your sight without warning. The findings were published in the British Journal of Ophthalmology and reported by the BMJ Group on 7 September 2026. Tadalafil is probably better known by its original brand name, Cialis. Many people think of it only as a treatment for erectile dysfunction. But it is also widely prescribed for the urinary problems caused by an enlarged prostate, a very common issue in older men. Taken that way, it is usually a low daily dose, taken for years. The researchers used a large international database of anonymised health records called TriNetX. They looked at 73,854 men aged 40 and over. Half of them, 36,927 men, had been prescribed tadalafil or a similar medicine for up to five years between 2012 and 2022. The other 36,927 had not. The two groups were carefully matched. That means the researchers paired men who were similar in age, ethnicity, smoking status, other health conditions and other medicines they were taking. The idea is to compare like with like as far as possible. Over five years of follow-up, the men taking tadalafil were: - 22 per cent more likely to be diagnosed with glaucoma - 32 per cent more likely to develop ocular hypertension, which means raised pressure inside the eye - 33 per cent more likely to be diagnosed with primary open-angle glaucoma, the most common type - 33 per cent more likely to be started on treatment for glaucoma The research team was led by Yun Hsia, Chien-Yun Tsai, Sheng-Chun Hung and colleagues.
Why this matters
Glaucoma is not a rare condition. It is one of the leading causes of permanent sight loss in the UK. What makes it so serious is how quietly it starts. Glaucoma damages the optic nerve, the cable that carries pictures from the eye to the brain. In the most common type, the damage begins at the edges of your vision. Your brain is very good at filling in the gaps, so most people notice nothing at all for years. By the time you can tell something is wrong, some sight has already gone. And here is the hard part: sight lost to glaucoma does not come back. Treatment can slow or stop further damage, but it cannot undo what has happened. That is why a study like this is worth paying attention to, even though the risk to any one person is small. Tadalafil is taken by a very large number of men, often for many years, and often for their prostate rather than for anything to do with sex. If a small extra risk applies to a very large group of people, it adds up. It is also worth saying plainly: this is not a reason to panic, and it is definitely not a reason to stop taking a medicine your doctor prescribed. It is a reason to get your eyes checked.
What the evidence actually says
Good science comes with limits attached, and the researchers were open about theirs. This was an observational study. That means the researchers watched what happened to two groups of people. They did not randomly decide who got the medicine and who did not. So the study can show a link, but it cannot prove that tadalafil causes glaucoma. There may be other explanations. Men who are prescribed tadalafil for prostate symptoms are, by definition, men who go to the doctor. They may also see an optometrist more often, which means glaucoma is more likely to be spotted in them than in men who never get checked. That alone could explain part of the difference. The researchers also could not track whether people kept taking the medicine, stopped, or switched to something else over the years. Most of the men in the database were White, so the results may not apply equally to everyone. And the percentages need reading carefully. A 22 per cent increase sounds alarming. But it is 22 per cent on top of a fairly small starting risk, not a 22 in 100 chance of going blind. For most men the absolute risk stays low. The study authors were clear about what they think should happen next. In their words, the findings 'do not contraindicate tadalafil use but highlight the importance of baseline ophthalmic assessment and regular follow-up, particularly in patients with pre-existing glaucoma'. In plain English: keep taking it, and get your eyes looked at.
Qurexa perspective
A lot of the men this study is about will be on a repeat prescription. Tadalafil for prostate symptoms is typically a daily tablet, ordered again and again, month after month. We deliver a great many repeat prescriptions across Lincolnshire and beyond, and we see how easily a long-standing medicine becomes invisible. It arrives, you take it, you do not think about it. That is exactly how it should be for a medicine that is working. But it does mean news like this can pass people by completely. Nobody re-reads the leaflet on year four. So if you or someone you look after takes tadalafil, treat this as a nudge rather than an alarm. Keep the medicine coming. Add an eye test to the list. Your community pharmacist can talk this through with you at no cost and without an appointment, and they can tell you whether anything else you take is worth mentioning to the optometrist.
Practical advice
Here is what is actually worth doing. **Do not stop your medicine.** Stopping a prostate medicine on your own can bring the urinary symptoms straight back, and stopping suddenly is never a good way to handle a worry about a tablet. Speak to your GP or pharmacist first. **Book a sight test.** This is the single most useful thing you can do. A routine sight test at any high street optician includes checks for glaucoma: the pressure inside your eye, the health of your optic nerve, and a test of your side vision. **Check whether yours is free.** In England, NHS sight tests are free if you are 60 or over. They are also free if you are 40 or over and have a parent, brother, sister or child with glaucoma, and if you have been diagnosed with glaucoma or ocular hypertension yourself. If you are not sure, just ask at the practice when you book. **Tell the optometrist what you take.** Bring your repeat prescription list, or a photo of it on your phone. It takes ten seconds and it genuinely changes what they look for. **Know the emergency signs.** A rarer form of glaucoma comes on suddenly. If you get severe eye pain, redness, blurred vision, headache, feeling sick, or you see rainbow-coloured rings around lights, do not wait. Call 111 or go to an eye casualty or A&E the same day. **If you already have glaucoma**, mention this study at your next appointment. The researchers singled out exactly this group as the people who most need regular follow-up.
What to know
A study of nearly 74,000 men found that those prescribed tadalafil were around 22 per cent more likely to be diagnosed with glaucoma over five years, and around a third more likely to be started on glaucoma treatment. The study cannot prove the medicine caused it, and the researchers themselves say the results are not a reason to stop taking it. What they are is a good reason to have your eyes checked properly and regularly. Glaucoma is quiet, common and treatable if it is caught. A sight test takes about half an hour, and for many people it costs nothing. Sources: BMJ Group, 'Erectile dysfunction drug used to treat enlarged prostate symptoms may raise glaucoma risk', 7 September 2026, https://bmjgroup.com/erectile-dysfunction-drug-used-to-treat-enlarged-prostate-symptoms-may-raise-glaucoma-risk/ | ScienceDaily, 'Cialis linked to higher glaucoma risk in large study', 7 September 2026, https://www.sciencedaily.com/releases/2026/09/260906170134.htm | Hsia Y, Tsai C-Y, Hung S-C et al., 'Risk of glaucoma among patients using tadalafil for lower urinary tract symptoms: a multinational cohort study', British Journal of Ophthalmology, 2026, https://pubmed.ncbi.nlm.nih.gov/42552102/ This article is for general information and does not replace advice from a doctor, pharmacist or other qualified healthcare professional.
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