Medications for Erectile Dysfunction such as Viagra and Cialis May Increase Eye Problems, Study Says

Researchers have found that regular intake of medications against erectile dysfunction (ED) such as Cialis and Viagra may cause 85% of men significant eye problems.

A study recently published in the JAMA Ophthalmology revealed that men who took PDE5Is or phosphodiesterase type 5 inhibitors developed retinal vascular occlusion (or RVO), ischemic optic neuropathy (or ION), or serous retinal detachment (or SRD). These three conditions can cause blindness.

PDE5Is are known in the market by laypeople and users as Viagra (sildenafil), Cialis (tadalafil), Stendra (avanafil), and Staxyn and Levitra (vardenafil).

The University of British Columbia research team used 213 033 males in the IQVIA database PharMetrics Plus who regularly took PDE5I medications from Jan. 1, 2006, to Dec. 31, 2020. The researchers compared these subjects to 4,584 males who did not take PDE5Is regularly. They excluded individuals who had been diagnosed with RVO, ION, and SRD in the previous year. The average age of men in both study groups was 64.6 years.

Occurrences of Problems in Vision in Regular PDE5I Users

During the study period, the researchers found 628 RVO cases, 240 ION cases, and 278 SRD cases in regular users. These males also had a higher likelihood of having chronic medical conditions, including diabetes, hypertension, sleep apnea, and coronary artery disease. But regardless of these risk factors, the ones who regularly took ED medications remained 85% more susceptible to one of the three eye diseases, Healthline reports.

Regular users were 44% more susceptible to RVO, 102% more vulnerable to ION, and 158% more susceptible to SRD. This means 8.5 more RVO cases, 3.2 more ION cases, and 3.8 more SRD cases per 10,000 individual years.

SRD or serous/exudative retinal detachment is a rare condition of retinal detachment that occurs when fluid accumulation under the retina pushes it further away from blood vessels. Disrupting retinal and optic nerve blood flow interrupts the visual pathway, resulting in ION. Meanwhile, when veins that carry blood away from the retina are blocked, it results in RVO. These three conditions are severe and require emergency care.

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ED medications such as tadalafil and sildenafil could affect blood flow in the optic nerves and eyes by inhibiting phosphodiesterase enzymes from degrading GMP or cyclic guanosine monophosphate and cAMP or cyclic adenosine monophosphate. When the levels of these two substances increase, the smooth muscles relax and cause an expansion and dilation of blood vessels. These expanded blood vessels provide more blood to the penis and cause it to erect.

PDE5Is act not only on the blood vessels in the penis but also throughout the body, which includes those affecting vision.

Correlation is Not Necessarily Causation

The current publication is just an observational cohort research study and has not proven causation. Recent incidences of RVO, ION, and SRD are still low. However, it is still not prudent to treat PDE5I medications lightly. Previous studies have also shown links between the drugs and severe eye conditions, Forbes reports.

Indiscriminate intake of ED medications may have serious negative consequences, and it helps to consult your doctor about it.

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