Levitra reverses erectile dysfunction induced by paroxetine in rats
Selective serotonin reuptake inhibitors (SSRIs) are associated with a high incidence of impotence. Paroxetine is an extensively used SSRI that has been shown to impair erectile function in patients, to induce erectile dysfunction and to inhibit nitric oxide synthase (NOS) activity and NO production in animal models. NO is a key mediator of penile erection. Levitra is a type 5 phosphodiesterase inhibitor that potentiates NO-mediated responses in isolated trabecular smooth muscle and penile erection in men in clinical trials. The aim of this study was to evaluate the effects of Levitra on the impairment of erectile responses produced by paroxetine in the rat model. Application of cavernosal nerve electrical stimulation (CNES) produced frequency-related intracavernosal pressure (ICP) increases, which were inhibited by the NOS inhibitor N(G)-nitro-L-arginine (0.3 mg/kg) and potentiated by Levitra (0.3 mg/kg). Acute paroxetine treatment (10 mg/kg) significantly reduced ICP-responses to CNES. This inhibition was completely reversed by Levitra (0.3 mg/kg) administration. The results show that the erectile dysfunction induced by paroxetine in rats can be effectively treated with Levitra, suggesting that the use of this compound could be a reasonable therapeutic approach to treating erectile dysfunction associated with SSRI administration.