Recreational use and misuse of phosphodiesterase 5 inhibitors

Objective: To characterize the rationale for and extent of phosphodiesterase (PDE) 5 inhibitor use in recreational settings, describe risks from such misuse, and discuss postexposure clinical management strategies. Data Sources: Published articles identified by searches through Medline, EMBASE, International Pharmaceutical Abstracts, and Toxline, from 1990 to March 2004, using the search terms sildenafil, tadalafil, vardenafil, phosphodiesterase inhibitor, abuse, overdose, adverse effects, recreational, and street drugs. Additional references identified within articles and information from the Internet were included. Study Selection: Clinical trials, epiderniologic reviews, case reports, and news releases concerning the misuse of sildenafil. Data Extraction: By the authors. Data Synthesis: PDE5 inhibitors, indicated for treatment of erectile dysfunction, can produce several adverse effects, including potentially fatal cardiovascular events. Reports of recreational use and misuse of sildenafil appear in the medical literature and the media. The potential for abuse also exists for the two more recently approved drugs in this class, vardenafil and tadalafil. Increasing access to these drugs via the Internet may facilitate such misuse. Use in social settings has gained popularity, both in young, healthy patients, as well as those with chronic medical conditions, including human immunodeficiency virus infections. In these settings, the PDE5 inhibitors are sometimes used concomitantly with "club drugs" such as ketamine and amyl nitrite, leading to potentially harmful or fatal drug interactions. Conclusion: Pharmacists should be cognizant of the potential for PDE5 inhibitors to be misused, particularly in patients who are at greater risk of cardiovascular complications, and should advise patients and other health care professionals accordingly.