Objective To investigate the relationship between concentration change of serum 5‐hydroxy tryptamine and clinical symptoms improvement in primary premature ejaculation with the treatment of paroxitine .Methods 81 cases of lifelong PE and an intra‐vaginal ejaculation latency time (IELT ) ≤60 s were included in this study .Subjects were divided into 2 groups according to the IELT ,group A (IELT≤30 s) and group B (30 s

Objective To compare the efficacy and safety of paroxetine alone and combined with folic acid in patients complaining of premature ejaculation ,and measured the 5-hydroxyptamine(5-HT ) concentration in two groups before and after treatment and compared the differences .Methods 126 cases of PE were included from department of Urology of 363 Hospital of Chengdu .Subjects were randomly divided into 2 groups ,group A were given paroxetine hydrochloride 20 mg/d ,group B were given paroxetine hydrochloride 20 mg/d and fo-lic acid 0 .4 mg/d ,study duration was 8 weeks .Blood sample got from the candidates both in screening period and after 8 weeks of treatment .The efficiency after treatment was measured by IELT and PEP ,the plasma 5-HT level was measured too .SPSS16 .0 statistical analysis was used .Results After treatment ,IELT of group A and group B was improved from 1 .21 ,1 .18 min to 8 .04 ,9 .42 min .The improvement of average IELT in group B was significantly higher than that in group A ,the difference was statistically significant (P＜0 .05) ;The PEP score and 5-HT level in group B were significantly higher than that in group A ,the difference was statistically significant (P＜0 .05) .Conclusion Paroxetine combined with folic acid in the treatment of primary premature ejaculation has a significant effect ,compared to paroxetine alone .The average plasma level of 5-HT increased significantly ,and folic acid could assist paroxetine in elevating plasma levels of 5-HT and improving primary premature ejaculation symptoms .