Objectives: One-third of patients with untreated depression have sexual difficulties manifested by decreased libido, erectile dysfunction or delayed ejaculation. This dysfunction may be exacerbated by stimulation of post-synaptic serotonin 5HT2 receptors, a side-effect of most widely-used antidepressant medications, especially the selective serotonin reuptake inhibitors (SSRIs). Mirtazapine is an atypical antidepressant with alpha 2 adrenergic antagonist and serotonin 5-HT2 and 5-HT3 receptor-blocking activity. In theory, it should not worsen and perhaps may improve sexual function. This pilot study investigated sexual functioning and antidepressant activity in depressed patients taking mirtazapine.
Experimental design: Twenty-five (F = 18, M = 7) sexually active adult outpatients with a DSM-IV-diagnosis of major depressive episode entered a 12-week, flexible-dosing, open-label pilot study. The Arizona Sexual Experiences Scale (ASEX) assessed sexual functioning and the Hamilton Depression Rating Scale (HAM-D) assessed depressive symptoms on a bimonthly basis.
Principal observations: Desire, arousal/lubrication, and ease/satisfaction of orgasm improved (by 41%, 52%, and 48%, respectively) in the depressed women. In men, desire, arousal/erection, and ease/satisfaction of orgasm also improved (by 10%, 23% and 14%, respectively) but much more modestly. HAM-D, Clinical Global Impression (CGI) Sheehan Disability Scale (SDS), and Symptom Checklist-90 (SCL-90) scores improved in both groups. There was a 50% dropout rate among women before six weeks of treatment. However, the ASEX and HAM-D scores of the groups terminating before and after six weeks of treatment showed similar rates of improvement.
Conclusions: Mirtazapine has a beneficial effect on sexual functioning in both depressed women and men. Longer-term double-blind research assessing sexual function during the administration of mirtazapine as well as other antidepressants is recommended.