Introduction: Men with comorbid erectile dysfunction (ED) and premature ejaculation (PE) may be concomitantly prescribed a phosphodiesterase type 5 (PDE5) inhibitor and dapoxetine.

Aim: Evaluate efficacy and safety of dapoxetine 30 mg and 60 mg on demand (prn) in men with PE and ED who were being treated with PDE5 inhibitors.

Methods: This randomized, double-blind, placebo-controlled, flexible-dose, multicenter study enrolled men ≥18 years who met diagnostic criteria for PE including intravaginal ejaculatory latency time (IELT) of ≤2 minutes in ≥75% of sexual intercourse episodes; were on stable regimen of a PDE5 inhibitor; and had International Index of Erectile Function-erectile function domain score ≥21. Subjects received placebo, dapoxetine 30 mg, or dapoxetine 60 mg prn (1-3 hours before intercourse) for 12 weeks.

Main outcome measure: Stopwatch-measured average IELT, Clinical Global Impression of Change (CGIC) in PE, Premature Ejaculation Profile (PEP), and treatment-emergent adverse events (TEAEs).

Results: Of 495 subjects randomized, 429 completed the study. Arithmetic mean average IELT significantly increased with dapoxetine vs. placebo at end point (5.2 vs. 3.4 minutes) and weeks 4, 8, and 12 (P ≤ 0.002 for all). Men who described their PE at least "better" using the CGIC were significantly greater with dapoxetine vs. placebo at end point (56.5% vs. 35.4%) and weeks 4, 8, and 12 (P ≤ 0.001 for all). Significantly better outcomes were also reported with dapoxetine vs. placebo on PEP measures. Incidence of TEAEs was 20.0% and 29.6% in placebo- and dapoxetine-treated subjects, respectively (P = 0.0135). TEAEs led to discontinuation in 1.6% of subjects in both groups. Most frequent TEAEs were known adverse drug reactions of dapoxetine treatment including nausea (9.2%), headache (4.4%), diarrhea (3.6%), dizziness (2.4%), and dizziness postural (2.4%).

Conclusions: In men with PE and comorbid ED on a stable regimen of PDE5 inhibitor, dapoxetine provided meaningful treatment benefit and was generally well tolerated.