Rationale and objectives: We tested the hypothesis that the selective reversible MAO-A inhibitor moclobemide has a specific therapeutic effect on erectile dysfunction independent of its antidepressive properties.
Methods: In a double-blind placebo controlled study, 12 male outpatients suffering from psychogenic erectile dysfunction without any other psychiatric disorder were investigated. Based on comprehensive diagnosis before the beginning of the study, organic factors relevant for sexual function were excluded. The treatment period was 8 weeks. Half the patients received 450 mg moclobemide during the first week, and 600 mg afterwards; the others received placebo. Apart from assessment of erectile function by means of the Clinical Global Impression (CGI) scale, nocturnal erections were measured under polysomnographic control at baseline and at the end of the treatment period.
Results: The evaluation of the CGI scale revealed a clearly stronger improvement under moclobemide compared to placebo during the study period. The therapeutic efficacy found on the subjective level had no clear correlate on the neurophysiological level. No alterations of nocturnal erectile parameters were obvious under treatment, neither were clinically relevant alterations found regarding sleep EEG parameters. The medication was well tolerated without serious adverse events.
Conclusions: The findings support the hypothesis that moclobemide has a specific effect on erectile dysfunction. Thus, patients suffering from psychogenic erectile dysfunction who are not depressed might benefit from moclobemide without relevant side effects.