Assessment of the efficacy and safety of Viagra® (sildenafil citrate) in men with erectile dysfunction during long-term treatment

Abstract

Long-term efficacy and safety of sildenafil was assessed in 1008 patients with erectile dysfunction (ED) enrolled in four flexible-dose (25 -100 mg), open-label, 36-or 52-week extension studies. After 36 and 52 weeks, 92% and 89% of patients felt that treatment with sildenafil had improved their erections. Responses to a Sexual Function Questionnaire indicated that 52 weeks of sildenafil treatment resulted in clinically significant improvements in the duration and firmness of erections, overall satisfaction with sex life, and the frequency of stimulated erections. Commonly reported adverse events (AEs) were headache, flushing, dyspepsia, and rhinitis, which were generally mild to moderate. Reports of abnormal vision were consistent with previous clinical trials. The occurrence of treatment-related cardiovascular AEs, such as hypertension, tachycardia, and palpitation, was < 1%. Discontinuations due to treatment-related AEs were low (2%). Long-term therapy does not diminish the efficacy of sildenafil in patients with ED and remains well tolerated.

Post-marketing surveillance study of the safety and efficacy of sildenafil prescribed in primary care to erectile dysfunction patients

“…This relatively low reporting of adverse events has been observed in foreign clinical trials that are either open-ended or target primary care facilities. 11,21 Our finding that very few patients discontinued treatment was in agreement with that of other trials. 11,14,20,21 The current trial is not without limitations.…”

“…11,21 Our finding that very few patients discontinued treatment was in agreement with that of other trials. 11,14,20,21 The current trial is not without limitations. First, there is no way to accurately determine how much the placebo effect improved erectile function.…”

Sildenafil citrate efficacy 8 h postdose in men with mild to moderate erectile dysfunction

“…5 The main treatment-related adverse events reported in clinical studies are headache, facial flushing and dyspepsia. 6 These are usually transient and mild to moderate in severity. The recommended starting dose of sildenafil is 50 mg.…”

“…Although a few men cannot tolerate sildenafil 50 mg and have their dose reduced to 25 mg, the majority of men are titrated to a 100 mg dose for optimal efficacy. 6 In men with ED, empirical observations and the results of clinical trials suggest that the duration of sildenafil activity may be much longer than the 4-5 h currently described in the manufacturer's prescribing information. 7,8 The 4-5 h duration of activity for sildenafil on erectile response was inferred from its pharmacokinetic characteristics (that is, the achievement of maximum plasma concentrations within 1 h and a terminal elimination half-life of between 3 and 6 h).…”

Topical application of a Rho-kinase inhibitor in rats causes penile erection

“…4 Phosphodiesterase 5 inhibitors, which slow the degradation of cGMP and hence facilitate erection, are effective when given orally, are convenient to use and are well tolerated. 5,6 However, despite the variety of pharmacological treatment options available, each has shortcomings and contraindications so that the search for the safest and most effective treatment for ED must continue. 7,8 It has recently been demonstrated that a previously uninvestigated biochemical pathway may regulate smooth muscle contraction in the cavernosal circulation.…”