Effects of fenfluramine on ejaculatory function, luteinizing hormone and testosterone levels in men with hypogonadotropic hypogonadism and premature ejaculation.

Serotonergic neurotransmission is associated with the regulation of aggressive behaviour, anxiety and affect. Serotonin (5-HT) reuptake inhibitors (SRIs) have been extensively utilized in the treatment of affective disorders; however, their use often results in ejaculatory inhibition. Serotonin appears to modulate male sexual function through its influence on luteinizing hormone (LH) secretion but only when the steady state is altered. Premature ejaculation (PME) is defined as persistent or recurrent ejaculation with minimal sexual stimulation (DMS-III-R). While the aetiology of PME remains unclear, an underlying anxiety disorder may be a major contributing factor. It has been recently suggested that patients with premature ejaculation (PME) have an associated hypogonadotropic hypogonadism. This study was undertaken to determine whether the administration of the SRI fenfluramine would result in changes in PME (inhibitory effect) and release of LH which could be indirectly measured through an increase in the production of testosterone (disinhibitory effect). Six patients with PME and hypogonadotropic hypogonadism were treated with fenfluramine (20 mg). Both inhibition of PME (based on graded couple's responses) and increased plasma LH and testosterone levels occurred following treatment. These observations strongly suggest a role for serotonergic modulation in the occurrence of PME.