Efficacy of Sildenafil Citrate at 12 Hours after Dosing: Re-exploring the Therapeutic Window

Early sildenafil dose optimization and personalized instruction improves the frequency, flexibility, and success of sexual intercourse in men with erectile dysfunction

“…This was an 8-week, multicenter, open-label, flexible-dose study of sildenafil (25,50 and 100 mg, PRN) that was conducted in two phases. Patients completed the International Index of Erectile Function (IIEF) 15 at baseline to determine their severity of ED.…”

Phosphodiesterase type 5 inhibitors’ extended duration of response as a variable in the treatment of erectile dysfunction

“…Both sildenafil and vardenafil have half-lives of about 4-5 h. 4,5,17 There has been one recent report indicating a duration of action for sildenafil up to 12 h and another study with vardenafil showing comparable duration. 18,19 Prospective clinical trials have shown that the half-life of tadalafil is 17.5 h and its erectogenic effects are sustained for up to 36 h. 6,[20][21][22] Shabsigh et al's 23 clinical trial data analysis alerted clinicians to patients' willingness (facilitated by tadalafil's extended duration of action) to initiate sexual experiences beyond the 4-h window frequently described in the literature.…”

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

“…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). 9 However, previously published clinical trial results support a longer duration of activity.…”

“…9 However, previously published clinical trial results support a longer duration of activity. 8,10 A better definition of the period of responsiveness to sildenafil would assist in its optimal use. Recently, a randomized, double-blind, placebo-controlled trial of sildenafil 100 mg in men with mild to moderate ED prospectively assessed sexual intercourse attempted at 8 h postdose and (after crossover to the alternative treatment) 12 h postdose during sequential, 4-week treatment periods.…”