Excessive use of erectile dysfunction drug has been linked to an irreversible color vision damage in a 31-year-old man.
Richard Rosen, the director of Retina Services at New York Eye and Ear Infirmary of Mount Sinai (NYEE), and colleagues reported the case of the patient who arrived at an urgent care clinic because of red-tinted vision in both of his eyes that had persisted for two days.
According to the case study detailed in Retinal Cases and Brief Reports, the man’s vision problem started soon after he took an unknown amount of liquid sildenafil citrate he bought online. Sildenafil can be bought as a generic drug for erectile dysfunction and under the brand name Viagra.
It turned out that the patient consumed more than the recommended 50 mg dose and his symptoms showed up shortly after ingestion. He was eventually diagnosed with persistent retinal toxicity, which doctors linked to taking high dose of the medication.
Normal dose of sildenafil citrate can cause visual disturbances, but the symptoms often resolve within 24 hours. Unfortunately, in this case, the man’s tinted vision has not improved even after more than a year of initial diagnosis and treatments.
Doctors who examined the man’s eyes saw microscopic injury to the cones of the retina that are responsible for color vision.
“To actually see these types of structural changes was unexpected, but it explained the symptoms that the patient suffered from. While we know colored vision disturbance is a well-described side effect of this medication, we have never been able to visualize the structural effect of the drug on the retina until now,” Rosen said in a statement published by Mount Sinai.
The doctors said that the damage is similar to those of hereditary retinal diseases.
“Patient was found to have cone photoreceptor damage, demonstrated using electroretinogram, optical coherence tomography, and adaptive optics imaging. The patient’s symptoms and the photoreceptor structural changes persisted for several months,” the researchers wrote in their study.
The drug was notably bought online. Rosen and colleagues cannot rule out the possibility that a contaminant may have contributed to the man’s condition. Nonetheless, the case still underscores the danger of using drugs beyond the recommended dosage.
Rosen and colleagues said that their findings should help doctors become aware of the cellular changes that may occur in patients that use the drug excessively. They could warn their patients about the risks of using too much of the medication.
Other unwanted side effects of using the drug heavily include heart attack and long erections that may cause the penis to develop gangrene.
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