Tadalafil, a medication commonly used to treat erectile dysfunction, is also prescribed for symptoms associated with an enlarged prostate. Recent research has indicated a potential link between the long-term use of such medications and a heightened risk of serious eye conditions, including glaucoma.
Experts from Australia emphasize the importance of regular eye health assessments for individuals prescribed these medications, particularly for those with pre-existing risk factors for eye diseases. The study, published in the British Journal of Ophthalmology, examined a cohort of 74,000 men aged 40 and older, with half of the participants having received tadalafil (marketed under brand names like Cialis) over five years.
In addition to addressing erectile dysfunction, tadalafil is utilized for the management of urinary issues linked to an enlarged prostate. Findings revealed that long-term users of the drug were 22 percent more likely to develop glaucoma—an eye condition that can lead to blindness—compared to non-users.
Flora Hui, an optometrist and research fellow at the Centre for Eye Research in Australia, noted that this study is the first cohort analysis establishing a correlation between the use of these medications and an increased risk of glaucoma. While the statistical risk was higher among users, Hui reassured that the overall risk remains relatively low.
She stressed the necessity for eye examinations before and during the course of treatment with these medications, especially for individuals who are older or have a family history of glaucoma. “Regular eye tests are essential, as glaucoma can often be asymptomatic,” she cautioned.
Tadalafil belongs to a class of drugs known as phosphodiesterase type 5 inhibitors (PDE5i), which also includes sildenafil (commonly known as Viagra). Previous studies have identified various ocular side effects associated with PDE5i, but until now, no strong evidence had linked long-term use of tadalafil with the onset of glaucoma.
These inhibitors work by blocking a protein called PDE-5, which enhances blood flow to the penis, aiding in the ability to achieve and sustain an erection. Additionally, they relax muscle tissue and improve circulation in organs like the prostate and bladder.
While the exact mechanism by which these drugs may elevate the risk of glaucoma remains unclear, Dr. Hui proposed several theories. She explained that the body’s finite blood supply necessitates redistribution, which could lead to transient increases in eye pressure or reduced blood flow to the optic nerve—both potential contributors to glaucoma risk.
While the observational nature of the study does not confirm causation, it reveals a notable correlation that warrants further investigation. Andrew White, a clinician scientist ophthalmologist at Westmead Hospital, noted that not all users experience the same side effects, and some may encounter no adverse effects at all. He added that fluctuations in blood pressure could also exacerbate glaucoma conditions.
The Taiwanese-led study utilized data from 73,854 men sourced from the TriNetX international health database, excluding individuals with prior glaucoma diagnoses. Researchers compared 36,927 tadalafil users with an equal number of non-users of PDE5i medications.
In addition to the increased likelihood of developing glaucoma, the study found that those using tadalafil for urinary symptoms were 32 percent more likely to experience ocular hypertension and 33 percent more likely to begin glaucoma treatment than their non-using counterparts. The researchers concluded that tadalafil usage was significantly associated with an increased risk of glaucoma and related conditions, particularly in men over the age of 50.
However, the study has limitations, including a predominantly white participant group, which may affect the applicability of the results to men of different ethnic backgrounds. Additionally, researchers could not account for changes in medication or the emergence of other underlying health issues during the study period.
