Reboxetine-induced spontaneous ejaculation

Delayed or absent ejaculation is a common side-effect of antidepressant drugs. Reboxetine, a selective noradrenaline reuptake inhibitor, is known for its lack of sexual side-effects. We report a case of reboxetine-induced spontaneous ejaculation.

A 39-year-old married man was referred with recurrent depression. When euthymic his sexual function was normal. When depressed he had mildly decreased libido but normal erection, ejaculation and orgasm. He had poor response to, but no sexual side-effects with, fluoxetine 40 mg for 8 weeks. Later his depression improved with reboxetine 4 mg twice daily. However, he developed spontaneous ejaculations occurring 2-3 times a day. These were not preceded by sexual stimulation but were associated with pleasurable sensation. He also developed premature ejaculation during sexual intercourse. On discontinuing the medication, the spontaneous ejaculations and premature ejaculations subsided within 7 days.

This is the first report of reboxetine-induced spontaneous ejaculations. Seminal emission and ejaculation are controlled centrally by the anterior thalamic nuclei, preoptic nuclei and the median forebrain bundles, which are facilitated by dopamine and inhibited by 5-HT_1A antagonists and 5-HT₂ agonists. The spinal centres for emission, ejaculation and for bladder neck closure during ejaculation to prevent retrograde ejaculation are mediated by noradrenaline. Delayed, absent or retrograde ejaculation can be caused by sympatholytic antihypertensives, antipsychotics, selective serotonin reuptake inhibitors (SSRIs), surgical sympathectomy, spinal cord injury and diabetic autonomic neuropathy. The 5-HT_1A agonist 8-OH-DAPT, 5-HT₂ antagonists nefazodone and adrenergic agents such as ephedrine, pseudoephedrine and phenylephrine can reduce ejaculatory latency and revert retrograde ejaculation to antegrade ejaculation (Wang et al, 1996; Michael & O'Keane, 2000). Reboxetine is a selective and potent inhibitor of noradrenaline reuptake and has little effects on other neurotransmitter systems. This could explain its relative lack of sexual side-effects. Reboxetine could have caused decreased ejaculatory latency as well as spontaneous ejaculations by reuptake inhibition and consequent increased activity of noradrenaline. Michael et al (1999) used the ability of nefazodone to cause spontaneous ejaculation by virtue of its 5-HT₂ antagonist effect to reverse SSRI-induced anorgasmia. Reboxetine could be a potential substitute for antidepressants which cause delayed or absent ejaculation/orgasm.