Evaluation of the safety of sildenafil for male erectile dysfunction: experience gained in general practice use in England in 1999.

OBJECTIVE: To examine the safety of sildenafil, the first of the phosphodiesterase type 5 inhibitors licensed for the treatment of male erectile dysfunction (ED), as used in general medical practice in England, quantifying the incidence of a range of events in patients treated with sildenafil, and identifying any previously unrecognized adverse drug reactions.
METHODS: In a postmarketing observational cohort study using prescription-event monitoring (PEM), exposure data were derived from dispensed prescription details for patients who started treatment between April and August 1999. Outcome data were derived from "green form" questionnaires (GFs) returned by general practitioners (GPs). RESULTS In all, 24 835 (54.7%) of GFs posted to GPs were returned, of which 22 473 contained useful data for 22 471 male and two female patients. The major primary indications/clinical context of prescribing were impotence (16 583, 73.8%) and diabetes mellitus (183, 0.8%); 145 events were reported as adverse drug reactions to sildenafil. GPs recorded 3951 reasons for stopping sildenafil, and ischaemic heart disease (IHD) in 135 patients was the commonest clinical reason reported. The clinical condition reported most frequently in the first month of observation was diabetes mellitus and/or hyperglycaemia (in 99 events). A standardized mortality ratio (SMR) for deaths caused by IHD in the first 8893 of 22 473 patients was 31.41 (95% confidence interval 18.29-50.29), using the comparator population of males in England in 1998.
CONCLUSION: This study identified the safety profile of sildenafil as used in the community, showing no unexpected events. The SMR analysis of deaths from IHD provided no evidence to suggest a higher incidence of deaths in the study cohort than in the male population in England.