Sildenafil (VIAGRA) and its effects on the heart: No all-clear signal!
"Safe Sex with sildenafil in men with CAD", summarized the 'Ärztezeitung' recently (19 February 2002). This in spite of the fact that VIAGRA, the vasodilating drug against erectile dysfunction, has been associated with a number of adverse effects such as myocardial infarction, stroke, syncopes and arrhythmias since it had first been introduced. As of October 2001, more than 1,000 deaths worldwide have been attributed to the drug (a-t 2001; 32: 101). Since in the context of spontaneous postmarketing surveillance only about 2% of cases that actually happen are reported (SCHÖNHÖFER, P.S. et al: DGPT-Forum No. 28, Febr. 2002: 15-9), 50,000 cases of death could have actually occurred. Men with coronary artery disease (CAD) are considered to be especially vulnerable. Heart failure, diabetes mellitus and hypertension also increase the risk of developing erectile dysfunction. As yet, there are no valid criteria that predict for which of these patients sildenafil would be safe. The latest crossover trial, designed to study the safety of sildenafil in men with CAD now cited as an all-clear signal for its use, does not provide any additional data regarding its safety. The study which consisted of 105 participants could only exclude risks that occurred in more than 3% of cases with 95% confidence. The objective of this study was to assess hemodynamic effects of sildenafil during exercise in supine position on an ergometer bicycle. The primary endpoint of the study was a surrogate parameter: to evaluate ischemia induced changes of cardiac wall motions by echocardiography, to be scored on a 5-point grading system. The double-blind crossover study was conducted on two occasions separated by an interval of 1 to 3 days at which time the randomized participants received either a dose of 50 mg or 100 mg of sildenafil on day one and a placebo on day two or vice versa - a placebo on day one and sildenafil on day two. There were no significant differences in either the primary endpoint nor additional echocardiographic parameters such as ejection fraction and the mean heart rate during the exercise or the overall exercise capacity. Sixty-nine men (66%) who took sildenafil developed dyspnea or angina as compared to 70 men (67%) who took placebo. There were no acute myocardial infarction, ventricular fibrillation or death in either group. However, after the use of sildenafil, the systolic blood pressure decreased significantly by a mean of 7 mm Hg. The mean diastolic blood pressure was also significantly lower after sildenafil than after intake of placebo. Following the higher dose of sildenafil, one participant (1%) experienced a drop of blood pressure to 70/50 mm Hg which lasted for 20 minutes and was treated with intravenous infusion of isotonic sodium chloride. This event has not been mentioned in the abstract. Under sildenafil, six men (6%) received nasal oxygen following the exercise as compared to two (2%) men under placebo. (ARRUDA-OLSON, A.M. et al.: JAMA 2002; 287: 719-25; ati d).