Vision Disorders and Phosphodiesterase Type 5 Inhibitors

Alan M. Laties

Phosphodiesterase type 5 (PDE-5) inhibitors (sildenafil, vardenafil and tadalafil) have been in widespread use for the safe and effective treatment of erectile dysfunction (ED) for nearly a decade. During that time, a relatively small number of patients have experienced adverse visual events, including nonarteritic anterior ischaemic optic neuropathy (NAION). In this article, post-marketing reports of adverse visual events along with other relevant literature on ocular safety related to PDE-5 inhibitor use are reviewed. Although a relatively small number of cases have been reported with a possible temporal association with PDE-5 inhibitor use, it has not been possible to conclude whether these events are coincidental or whether they are associated with effects of PDE-5 inhibitors on ocular circulation or on other structures of the eye. A careful review of pooled data from clinical trials for all three PDE-5 inhibitors, which contain well documented information about the dose and duration of exposure to the drug for a large number of patients, yields no evidence for an increased risk of NAION or other adverse ocular events associated with PDE-5 inhibitor use. However, the inherent limitations in interpreting results from clinical trials and potentially incomplete information from post-marketing surveillance preclude a definitive declaration that ocular safety will not be a concern for some patients with ED and co-morbid disease states. Despite the absence of a proven link between PDE-5 use and serious ocular disorders, physicians should continue to advise patients to stop use of a PDE-5 inhibitor and seek immediate medical attention in the event of a sudden loss of vision as a safety measure.