Popular erectile dysfunction drug linked to eye disease that can cause irreversible vision loss

Tadalafil Linked to Higher Glaucoma Risk in Large Long-Term Study

An international study involving tens of thousands of men has found a notable association between long-term use of tadalafil, a drug commonly prescribed for erectile dysfunction and enlarged prostate symptoms, and an increased risk of developing glaucoma and related eye conditions.

The research, published in the British Journal of Ophthalmology, drew on health records for nearly 74,000 men aged 40 and older who had been treated for lower urinary tract symptoms. Roughly half of the men, about 37,000, had been prescribed tadalafil, while the rest had no recorded use of phosphodiesterase type 5 inhibitors, the drug class that includes Cialis. Participants were tracked for up to five years.

Men taking tadalafil were 22 percent more likely to develop glaucoma overall than those not using the drugs. They were also 32 percent more likely to develop elevated pressure inside the eye, known as ocular hypertension, and 33 percent more likely to be diagnosed with primary open-angle glaucoma, the most common form of the disease.

The findings come with important caveats. Because the study was observational, it can only show an association between tadalafil and glaucoma, not that the medication directly causes the condition. The researchers also acknowledged they could not fully account for changes in medication use or the onset of other health issues over the study period. They emphasized that the results should not be interpreted as a reason to stop taking tadalafil, but rather as a signal that long-term users, especially those with other glaucoma risk factors, may benefit from regular eye exams.

Glaucoma often develops quietly. Dr. Valerie Kattouf, an optometrist at the Illinois Eye Institute who was not involved in the study, stressed that early-stage glaucoma frequently shows no noticeable visual symptoms. As the disease advances, people typically begin to lose their peripheral vision, sometimes without realizing it until the damage is significant. Kattouf noted that the condition is best caught through a comprehensive vision evaluation, including pressure checks and other diagnostic tests.

Certain groups may need to be especially vigilant. People with a family history of glaucoma, a history of elevated eye pressure, or severe nearsightedness already face a higher baseline risk. Kattouf suggested that those who take tadalafil daily over an extended period may also warrant closer monitoring. Anyone who uses the medication regularly should consider scheduling a comprehensive eye exam to establish a baseline and track any changes over time.

Tadalafil is sold under the brand name Cialis, manufactured by Eli Lilly, and is widely used in the United States and abroad. Fox News Digital reported reaching out to both Eli Lilly and the study’s researchers for comment.

The study adds to a broader conversation about the side effects and long-term safety of medications used by millions of men. While the absolute increase in glaucoma risk found in the research is modest, glaucoma itself is a leading cause of irreversible vision loss worldwide, making even small risk increases a matter of clinical interest. Eye care professionals say the findings underscore the value of routine vision screenings, particularly for patients on long-term medications who may not connect their prescriptions with potential effects on sight.

Researchers and clinicians agree on the next steps: patients should not discontinue tadalafil based on the study alone, but those who take it over many years, especially in combination with other glaucoma risk factors, should talk with their doctors about incorporating regular eye health monitoring into their care.