Objectives: To determine the efficacy of two α1-adrenoceptor antagonists with different affinities for α1-adrenoceptor subtypes, silodosin and naftopidil, in the treatment of premature ejaculation.
Methods: This was a prospective, open-label, multicenter trial. A total of 26 patients with untreated acquired premature ejaculation were enrolled. Premature ejaculation was defined based on the International Society for Sexual Medicine recommendation. Patients self-administered on demand silodosin 4 mg or naftopidil 25 mg 1 h before intercourse, alternating drugs at least three times each. Clinical global impression change for premature ejaculation, premature ejaculation profile, and intravaginal ejaculation latency time were evaluated at baseline and during treatment.
Results: Due to clinical global impression change, 24 patients (92%) and 12 patients (46%) reported improvement in their own premature ejaculation problems under silodosin and nafitopidil administration, respectively. Silodosin treatment produced a significantly higher improvement rate compared with naftopidil (P = 0.0002). Objectively, silodosin significantly prolonged intravaginal ejaculation latency time compared with baseline and naftopidil (P < 0.01). Mean intravaginal ejaculation latency times were 1.9, 4.1, and 7.6 min at baseline, control and with silodosin, respectively. The rate of reduced semen volume during silodosin treatment was higher than during naftopidil treatment. There were no adverse systemic effects in either group.
Conclusions: Silodosin, a highly selective α1A-adrenoceptor antagonist, produces greater improvements in premature ejaculation profiles and related symptoms along with intravaginal ejaculation latency time in acquired premature ejaculation patients with or without erectile dysfunction. This result supports the clinical use of silodosin as an alternative treatment for premature ejaculation.
Keywords: intravaginal ejaculatory latency time; naftopidil; premature ejaculation; silodosin; α1-adrenoceptor antagonists.
© 2017 The Japanese Urological Association.