The randomised, double-blind, multicentre phase 3 study included 604 patients with PE, as defined by the Diagnostic and Statistical Manual of Mental Disorders 4th edition (intravaginal ejaculatory latency time [IELT] of under 2 minutes). Investigators examined two efficacy endpoints: prolongation of IELT and improvement in scores on the premature ejaculation profile (PEP), a validated, self-reported outcome instrument.
At each of the two tramadol doses tested, there was a significant increase in median IELT versus placebo, with a 2.37-fold increase for the lower dose and a 2.49-fold increase for the higher dose. The mean change for all four aspects of the PEP was significantly higher in both treatment groups than in the placebo group.
In total, 11.8% of participants experienced adverse events, with the most common event being erectile dysfunction. However, rates of withdrawal from the study did not differ to a significant degree between the treatment and placebo arms.
Two other smaller studies, published in the Journal of Clinical Psychopharmacology and the Journal of Sexual Medicine, also report that on-demand use of tramadol displays efficacy for the treatment of PE.
Also in the late stages of development for PE is a metered-dose topical spray containing the local anaesthetics lidocaine and prilocaine. PSD502 is applied to the head of the penis 5 minutes before intercourse and has displayed efficacy in two phase 3, double-blind, placebo-controlled studies in men with lifelong PE.
The SSRI dapoxetine (Priligy) was launched earlier this year for PE. Guidelines produced by the International Society for Sexual Medicine recommend dapoxetine, as well as off-label use of other SSRIs, TCAs, and topical anaesthetics, as treatment options for premature ejaculation. Priligy is not listed in MIMS as it is available only on private prescription.