The risk of developing one of three serious eye conditions increases by 85 percent for regular users of common erectile dysfunction (ED) medications such as the phosphodiesterase 5 (PDE5) inhibitors, sildenafil, tadalafil, vardenafil and avanafil, according to new research.
Previously, two of the three conditions had been linked to ED medications only by anecdotal case studies. Now, these links have been confirmed for the first time by a large, epidemiological study, which appears in JAMA Ophthalmology.
“These are rare conditions, and the risk of developing one remains very low for any individual user. However, the sheer number of prescriptions dispensed each month in the US – about 20 million – means that a significant number of people could be impacted,” said first author Dr Mahyar Etminan. “Regular users of these drugs who find any changes in their vision should take it seriously and seek medical attention.”
The researchers analysed health insurance claim records of 213 000 men in the US without a history of these eye problems in the year before they became regular users of ED medications.
They followed the records to see how many men developed one or more of the three conditions, and how that rate compared to men who didn’t use the medications. After accounting for conditions associated with eye problems, such as hypertension, diabetes and coronary artery disease, they found the increased risk for each to be as follows:
- Serous retinal detachment (SRD): 2.58x more likely than non-users
- Retinal vascular occlusion (RVO): 1.44x more likely than non-users
- Ischaemic optic neuropathy (ION): 2.02x more likely than non-users
A key limitation was that the study could only show correlation between eye conditions and use of these drugs, and could not prove causation. However, possible explanations can be found in the way ED medications function.
“These medications address erectile dysfunction by improving blood flow, but we know that they can also hinder blood flow in other parts of the body,” explained Dr Etminan. “So although our study doesn’t prove cause-and-effect, there is a mechanism by which these medications could conceivably lead to these problems. The totality of the evidence points toward a strong link.”
The potential risk of SRD and RVO is not covered in the information currently provided to patients along with their ED medications, unlike the ION risk which has been demonstrated by previous research.
Dr Etminan hopes his team’s work will change that. Patients who are unaware of all potential side effects might not seek help in time to avoid serious visual consequences.
Source: University of British Columbia
