Effects of Evodiamine on the Pharmacokinetics of Dapoxetine and Its Metabolite Desmethyl Dapoxetine in Rats

The objective of this work was to investigate the effect of orally administered evodiamine on the pharmacokinetics of dapoxetine and its active metabolite desmethyl dapoxetine in rats. Twelve healthy male Sprague-Dawley rats were randomly divided into 2 groups: the control group (received oral 10 mg/kg dapoxetine alone) and the combination group (10 mg/kg dapoxetine orally co-administered with 100 mg/kg evodiamine). The plasma concentration of dapoxetine and desmethyl dapoxetine were estimated by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), and different pharmacokinetic parameters were calculated using the Drug and Statistics 2.0 software. Compared to the control group, the pharmacokinetic parameter of t1/2, AUC(0-∞) and Tmax of dapoxetine in combination group was significantly increased by 63.3% (p < 0.01), 44.8% (p < 0.01) and 50.4% (p < 0.01), respectively. Moreover, evodiamine had significantly decreased the pharmacokinetic parameter of t1/2 and AUC(0-∞) of desmethyl dapoxetine. This study demonstrated that evodiamine inhibits the metabolism of dapoxetine. Henceforth, the pharmacodynamic influence of this interaction should be taken into consideration while prescribing dapoxetine to the patients already taking evodiamine.