AB151. Clinical study on the treatment of lifelong premature ejaculation with paroxetine hydrochloride and tamsulosin

Background and objective: There are some methods for the treatment of primary premature ejaculation (PE) at present, but its efficacy and safety is not very good and the effectiveness of some treatment method remains to be further confirmed. Psychotherapy and behavior training therapy has a poor adherence for patients. The surgical treatment to PE has not been widely recognized by experts because its effect of uncertainty and may cause irreversible damage. So, pharmaceutical drug therapy is usually recommended as the first priority selection for the treatment of PE. At present, only the dapoxetine was specifically developed for the treatment of PE worldwide. Other off-label selective serum reuptake inhibitor substance (SSRIs) such as paroxetine, fluoxetine; local anesthetics such as lidocaine, prilocaine cream; PDE5 inhibitor such as tadalafil, sildenafil and vardenafil; selective alpha-adrenergic receptor blockers such as tamsulosin, silodosin was also used for the treatment of PE. Owing to the individual differences and the different causes of PE, the efficacies of one medicine in different patients are different. So, individual-based treatment could be the trend for the treatment of PE according to the specific causes and its classification. There is quite a few researches focus on the combination treatment of SSRIs and α-receptor blockers to PE. In this study, the efficacy and safety using paroxetine and hydrochloric tamsulosin for the treatment of PE were evaluated, the serum concentration of 5-HT in the PE patients before and after treatment were assessed, and the mechanism of SSRIs for the treatment of PE were discussed.

Methods: A total of 225 cases of men with 18-65 years of age, a history of lifelong PE and an intra-vaginal ejaculation latency time (IELT) <120 sec were included in this study. The patients were randomized divided into three groups. Group A were given paroxetine hydrochloride 20 mg/d for 8 weeks; group B were given tamsulosin 0.2 mg/d for 8 weeks; group C were given paroxetine hydrochloride and tamsulosin at the same dosage as above for 8 weeks. The effects and adverse events were evaluated by the overall change and folds increase in average IELT and the mean change in all four measures of the premature ejaculation profile (PEP). Blood sample was got from the candidates before and after treatment. The plasma concentration of 5-HT was measured by ELISA. All the data were statistically analyzed.

Results: The reliable data from 198 patients were achieved. The mean IELT in group A was increased from 1.23 to 8.52 min and increased for 7.29 min after treatment; the mean IELT in group B was increased from 1.16 to 2.30 min and increased for 1.14 min after treatment; the mean IELT in group C was increased from 1.16 to 9.31 min and increased for 8.15 min after treatment; the mean IELT after treatment were significantly improved in all groups than that of before treatment (group B: P<0.01; group A,C: P<0.001). The increased folds of mean IELT in group C (8.02 folds) was significantly higher than that in group B (1.98 folds) and group A (6.92 folds) (P<0.001). The mean PEP scores that include measures of perceived control over ejaculation, satisfaction with sexual intercourse, ejaculation-related personal distress, and ejaculation-related interpersonal difficulty were significantly improved in all groups after treatment. The mean PEP scores in group C have more significant improvements than that in group A and B. The prevalence of adverse events in group A,B,C were 13.3% (10 cases), 2.6% (2 cases) and 12.0% (9 cases), respectively. The mean plasma concentration of 5-HT in group A,B,C before treatment was significant lower than that in normal control group (P<0.001). The mean plasma concentration of 5-HT in group A and C was significant improved (P<0.001) and there is no significant difference between group A and C after treatment (P>0.05). The plasma concentration of 5-HT in group B did not change after treatment (P>0.05).

Conclusions: Paroxetine hydrochloride combined with tamsulosin produce more better therapeutic effects and could be a priority selection for the treatment of primary PE. The plasma concentration of 5-HT can be used as the objective diagnostic index of primary PE, and to some extent, it is meaningful for the assessment of treatment effect of SSRIs.

Keywords: Premature ejaculation (PE); paroxetine; 5-HT; hydrochloride tamsulosin; selective serum reuptake inhibitor substance (SSRIs)