ObjectiveTo evaluate the efficacy and safety of injection of botulinum-A toxin into the bulbospongiosus muscle in the treatment of primary premature ejaculation (PPE).

METHODSAccording to the inclusion criteria, we randomly assigned 70 outpatients with PPE to a trial and a control group of equal number, the former injected with 100 U botulinum-A toxin at 10 U/ml and the latter with the same volume of saline into the bulbospongiosus muscle. Then, we obtained the intravaginal ejaculatory latency time (IELT), scores of the Premature Ejaculation Profile (PEP), Male Sexual Health Questionnaire-Ejaculatory Dysfunction (MSHQ-EjD), and Hospital Anxiety and Depression Scale (HADS), and the incidence of adverse reactions between the two groups before and 4 weeks after treatment.

RESULTSComplete data were obtained from 69 of the patients, 34 in the trial and 35 in the control group. The effectiveness rate was 47.06% (16/34) in the former but 0 in the latter. At 4 weeks after treatment, the patients of the trial group showed a significantly longer IELT than the controls and the baseline (［2.35 ± 1.83］ vs ［0.79 ± 0.21］ and ［0.74 ±+ 0.27］ min, P < 0.01) and the controls. The patients in the trial group, in comparison with those in the saline control group and the baseline, also exhibited significant improvement in the scores of PEP-ejaculation control (1.21 ± 1.04 vs 0.49 ± 0.56 and 0.47 ± 0.51, P < 0.05), PEP-sexual satisfaction (1.32 ± 1.01 vs 0.71 ± 0.57 and 0.79 ± 0.48, P < 0.05), PEP-PE-related distress (2.12 ± 1.01 vs 2.80 ± 0.68 and 2.76 ± 1.26, P < 0.05), and PEP-PE-induced difficult relationship with the partners (1.38 ± 0.70 vs 2.37 ± 0.55 and 2.12 ± 1.49, P < 0.05). The sexual satisfaction score of the female partners after treatment was markedly improved in the trial group as compared with the control group and the baseline (1.18 ± 1.00 vs 0.57 ± 0.50 and 0.62 ± 0.60, P < 0.05). There were no statistically significant differences in MSHQ-EjD and HADS scores between the two groups before and after treatment. Adverse reactions were observed in 6 cases (17.65%) in the trial group, including 4 cases of decreased erectile hardness (11.76%) and 2 cases of incomplete urination (5.88%), which occurred from the 3 to 4 days after injection, and those with decreased erectile hardness could complete sexual intercourse without any other treatment and recovered after 3 weeks.

CONCLUSIONSInjection of botulinum-A toxin into the bulbospongiosus muscle can be used as an option for the treatment of PPE. Its clinical application value, however, needs to be verified by further studies with larger samples.