A large comparative study published in the British Journal of Ophthalmology finds that tadalafil, a drug used to treat erectile dysfunction and symptoms associated with an enlarged prostate, may increase the risk of developing glaucoma. The findings were released on Aug. 4 and suggest that long-term use of tadalafil for this indication could warrant careful eye health monitoring, especially for patients with existing glaucoma risk factors.
Researchers analyzed anonymized data from 73,854 men aged at least 40 in the TriNetX Analytics Network. Half had been prescribed tadalafil or another phosphodiesterase type 5 inhibitor (PDE5i) for up to five years between January 2012 and December 2022 to manage urinary tract symptoms linked to benign prostatic hyperplasia; the other half had not received these drugs. The study assessed how likely both groups were to develop glaucoma, ocular hypertension, or begin treatment for glaucoma after five years.
The two groups were matched based on age, ethnicity, smoking status, alcohol-related disorders, underlying conditions such as cardiovascular disease and diabetes, obesity status, chronic obstructive pulmonary disease (COPD), kidney function, cancer history, high cholesterol levels, and prescribed medications.
Results showed that men prescribed tadalafil were significantly more likely—22% more—to develop glaucoma compared to those who did not take the drug. They also faced a 32% higher likelihood of developing ocular hypertension and a 33% increased chance of primary open angle glaucoma—the most common type—as well as starting treatment for glaucoma. These associations persisted among those who developed glaucoma within one month to six months after starting tadalafil treatment and remained consistent among patients aged over 50 years old or those with various underlying health conditions included in the analysis.
The researchers caution that this is an observational study, so no firm conclusions about cause and effect can be drawn. Limitations include not accounting for changes in medication usage or new medical conditions over time; most participants were White so results may not apply broadly across all ethnic backgrounds.
In their conclusion they write: "These findings suggest that chronic PDE5 inhibition may influence ocular physiology, warranting further mechanistic investigation." They add: "These 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, ocular hypertension, a family history of glaucoma, high myopia [short-sightedness], or those requiring long-term therapy."
