Premature ejaculation (PE) can be defined as a lack in the normal voluntary control over ejaculation and surely is the most common male sexual disorder.1 It has been traditionally considered a psychological defect, but in recent years many organic causes have been found,2 identified locally in the penis and in the central or peripheral nervous system. Consequently, a pharmacological way of relieving it has been researched3 and some drugs, as fluoxetine, paroxetine, clomipramine, etc. have been used with various results.4 We wish now to communicate the beneficial effects of another drug, levosulpiride, an anti-dopaminergic drug which is commonly used in some dyspeptic syndromes in anxious patients and to treat some types of hemicrania. We observed its effect on premature ejaculation accidentally, after prescribing the drug for its usual purpose to three patients. It was only by chance that all of them were suffering from premature ejaculation. During the following visit, after 20–30 days, we were surprised to hear of a wonderful improvement in their sexual life. This observation led us to set up an appropriate double-blind study. Forty-nine patients were chosen, who had been suffering from PE for at least the past 5 years. After having obtained informed consent, we carefully examined their medical histories, in order to avoid epileptic subjects and any kind of psychiatric pathology. Patients suffering from erectile disorders were not included in the study. We did not research the patients' ejaculatory latency times, because we did not intend to discriminate among different types of ejaculatory pathologies, we only wished to test the improving capacity of the drug. The patients' ages ranged between 29 and 55 y, with a mean of 41.4. Fifteen subjects were chosen adequately, in order to maintain a comparable mean age with the other group and were treated with placebo only. The remaining 34 received 25 mg of the drug once a day for 60 days. They were taught to record their latency times with a stop-watch and to report any incidental side effect. In every patient an assay for prolactin was performed before starting the trial, as the hyperprolactinemic effect of the drug in many subjects is well known and we wanted to evaluate the size of it in everyone and the possible relationship with the therapeutic effect of the drug.5 After 60 days the patients were followed-up. None of the patients were lost to follow-up. After collecting the results, the patients who had received the drug were divided in four groups, depending on the improvement rate they referred: A, B, C, D. In group A we put the subjects with a very good improvement, that was an improvement of more than 500% in the latency time (generally, these patients could last longer than 5 min, but we took care of the improvement rate only). Surprisingly, we had to note that this was the largest group, since 18 subjects were in it (52.94%). In the second group (B) we put the subjects who had some improvement, even though the latency time they achieved could not be considered as normal. The improvement rate in this group was a mean of 200% (with an achieved lasting time shorter than 5 min). Eight subjects were put in this group (23.53%). In groups C and D we put both poor responders and non responders, there were eight subjects in this category (23.53%). In the group of patients who received placebo, four subjects (26.66%) reported a very light improvement, since they achieved intra-vaginal ejaculation, but they did not last longer than 1 min. The remaining 11 subjects (73.33%) had no improvement at all. Only nine patients showed a significant rise of prolactin (more than 10%). No relationship was noticed between the prolactin rise and the percentage of improvement, as we could find this rise in each group. Only seven patients referred a fall in their libido, which was assumed as a potential side effect. Regarding the mechanism by which this drug might work we could hypothesise a close relationship with the ‘DA (Dopamine) theory’ of the control of human sexual function. Since DA seems to have a role in facilitating sexual arousal and in lowering the ejaculatory threshold, DA antagonists are likely to have an inhibitory function. Based on these results, we theorise that this drug could be quite reliable in the therapy of this very common male disorder and we would like to see further research from others.
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