Tadalafil isn't just for erectile dysfunction — it can also ease urinary symptoms caused by an enlarged prostate
A major study involving nearly 74,000 men has found that erectile dysfunction medication is associated with a significantly heightened risk of developing glaucoma, a potentially blinding eye condition.
Researchers at the National Taiwan University Hospital examined data from 73,854 men aged 40 and over, half of whom had been prescribed tadalafil — marketed as Cialis — or similar phosphodiesterase type 5 inhibitors (PDE5i) over a period spanning 2012 to 2022.
Those taking the drugs, which belong to the same pharmaceutical class as Viagra, were 22 per cent more likely to be diagnosed with glaucoma than men not using the medication.
The risk was even more pronounced for primary open-angle glaucoma, the most prevalent form of the condition, with men on PDE5 inhibitors 33 per cent more likely to develop it.
Patients taking the medication also faced a 32 per cent greater chance of developing ocular hypertension — elevated pressure within the eye that represents a significant precursor to glaucoma.
Additionally, those on the pills were roughly a third more likely to require treatment for glaucoma.
Perhaps most strikingly, a detailed sub-analysis demonstrated that the association emerged irrespective of treatment duration, with the elevated risk appearing after just one month of use.
Despite the findings, the study's authors stressed that patients ought not to discontinue their medication.
Rather, the research underscores the importance of routine eye examinations, particularly for individuals with additional risk factors such as a family history of glaucoma or short-sightedness.
The results "suggest that chronic PDE5 inhibition may influence ocular physiology, warranting further mechanistic investigation," the researchers wrote in the paper, which appeared in the British Journal of Ophthalmology.
Tadalafil is prescribed not only for erectile dysfunction but also to alleviate urinary symptoms associated with an enlarged prostate, including frequent and urgent urination.
The NHS currently issues close to five million prescriptions annually for PDE5 inhibitors, with Viagra accounting for the bulk of those.
In recent years, these drugs have also become available over the counter without the need for a prescription.
It is worth noting that the research is observational in nature, meaning other underlying health factors could partly explain the association.
Men who require such medication for erectile dysfunction or prostate problems may also be more susceptible to eye conditions owing to related issues such as obesity or elevated blood pressure.
Earlier studies have similarly drawn a connection between Viagra use and an increased risk of vision loss.
