Sex, the heart, and sildenafil

Effect of sildenafil citrate on the cardiovascular system

Sildenafil citrate is a drug commonly used to manage erectile dysfunction. It is designated chemically as 1-[[3-(6,7-dihydro-1-methyl-7-oxo-3-propyl-1H -pyrazolo[4,3-d]pyrimidin-5-yl)-4 ethoxyphenyl] sulfonyl]-4-methylpiperazine citrate (C22H30N6(O4)S). It is a highly selective inhibitor of cyclic guanine monophosphate-specific phosphodiesterase type 5. In late March through mid-November 1998, the US Food and Drug Administration (FDA) published a report on 130 confirmed deaths among men (mean age, 64 years) who received prescriptions for sildenafil citrate, a period during which >6 million outpatient prescriptions (representing about 50 million tablets) were dispensed. The US FDA recently reported that significant cardiovascular events, including sudden cardiac death, have occurred in men with erectile dysfunction who were taking sildenafil citrate. These reports have raised concerns that sildenafil citrate may increase the risk of cardiovascular events, particularly fatal arrhythmias, in patients with cardiovascular disease. In the past few years, the cardiac electrophysiological effects of sildenafil citrate have been investigated extensively in both animal and clinical studies. According to extensive data available to date, sildenafil citrate has been shown to pose minimal cardiovascular risks to healthy people taking this drug. Some precautions are needed for patients with cardiovascular diseases. However, the only absolute contraindication for sildenafil citrate is the concurrent use of nitrates. This article is intended to review sildenafil citrate's cardiovascular effects, as well as current debates about its arrhythmogenic effects.

Evaluation of acute risk for myocardial infarction in men treated with sildenafil citrate

Sexual intercourse is a rare trigger of acute myocardial infarction (MI). In the 2 hours after intercourse, the risk for MI is increased twofold to fourfold. However, there is limited information on the risk for MI after intercourse in men receiving treatment for erectile dysfunction. This study aimed to evaluate whether the use of sildenafil citrate in men with erectile dysfunction is associated with the triggering of acute MI. A self-matched case-crossover approach was used to evaluate the incidence of MI in men enrolled in 80 clinical trials of sildenafil at sites worldwide from 1993 to 2000. The risk for MI was assessed during 2 hazard periods: within 24 and within 6 hours after the ingestion of sildenafil. Relative risk was estimated using the Mantel-Haenszel estimator for sparse person-time data. A total of 69 MIs were observed during >11,000 person-years of exposure to sildenafil. The mean time between the last dose of sildenafil and the onset of MI was 14 +/- 2.9 days. The relative risk for MI was 0.80 (95% confidence interval [CI] 0.52 to 1.26) within 24 hours after taking sildenafil and 0.79 (95% CI 0.33 to 1.87) within 6 hours after taking sildenafil. In conclusion, these data indicate that sildenafil was not associated with short-term risk for MI and are consistent with the growing body of evidence that sildenafil use is not associated with an increased risk for cardiovascular events.

A 4-year update on the safety of sildenafil citrate (Viagra)

Clinical studies have demonstrated that sildenafil citrate (Viagra) is an effective and well-tolerated oral treatment for erectile dysfunction. Despite its established safety profile, concern about its cardiovascular safety persists among some physicians and the general public. This concern has stemmed primarily from sporadic reports of adverse events published in the literature and sensationalized by the media. However, the only absolute contraindication for sildenafil is concurrent use of nitrates. Because sildenafil has been on the market for 4 years and under clinical investigation for even longer, we can now evaluate its long-term safety in men who have been taking the drug for several years. We review this issue from 3 perspectives. First, we reassess the overall safety profile of sildenafil by reviewing the initial controlled clinical trials and open-label studies. We present new data from patients who have been exposed to sildenafil for up to 4.5 years. We also evaluate the results from independent postmarketing studies. Second, we review the cardiovascular-specific results from the clinical trials, long-term extension, and postmarketing studies. Lastly, we review the specific effects on the visual system based on findings from studies conducted during drug development and post marketing.