Although it is known that antidepressants, including the selective serotonin reuptake inhibitors (SSRIs), affect sexual function in men, adequate studies have not been conducted on women. Some patients continue antidepressant treatment after acute depression symptoms have resolved, but the results of treatment may linger. The physiology of SSRIs could relate to increased serotonergic tone inhibiting dopamine-related activation of sexual response. Buspirone and amantadine have been proposed, in uncontrolled case reports, as potential ameliorating agents. Michelson and associates evaluated the efficacy of buspirone and amantadine in the treatment of sexual dysfunction associated with fluoxetine administration.
Women 50 years or younger who had been taking a stable dosage of fluoxetine for at least eight weeks before study entry and who reported impaired orgasm or sexual arousal were enrolled in the four-week initial assessment period. Biweekly study visits were conducted, and the participants kept a daily diary in which they recorded mood and sexual function. Impairment of sexual function was assessed using clinician- and patient-rated global impressions. Fifty-seven participants were then randomly assigned to treatment with amantadine, in a dosage of 50 mg per day; buspirone, in a dosage of 20 mg per day; or placebo for an additional eight-week period. At baseline, pleasure and lubrication were rated as moderately impaired, while sexual interest and orgasm were more severely impaired.
Overall sexual function improved significantly in each of the study groups. Most individual items showed a similar degree of improvement. The degree of improvement from baseline on individual items was generally in the range of 20 to 50 percent. The groups were not significantly different from each other at baseline or end point with respect to mean frequency of sexual activity, and there was no significant change in frequency of sexual activity during the course of the study. There were no differences in the clinician-rated global impressions at end point among treatment groups on any measure. All groups showed improvement over the study period, and 27 percent of patients were given ratings of no sexual impairment by the end point.
Patients in the amantadine group reported significantly greater improvement in energy level at end point than the placebo-treated group. There was no difference in mean depression scores among any study participants.
The authors conclude that most aspects of sexual function can be influenced by nonspecific factors and that expectations substantially influence outcomes. The mean change in clinician-rated impressions of overall sexual function was almost one category (from moderate to minimal), and 27 percent of patients reported no or minimal symptoms at the end of the study. This result suggests that the degree of change observed was meaningful for some patients. The mechanisms underlying this improvement may relate to the intensive self-monitoring of sexual function and the regular clinic visits, as well as to nonspecific effects associated with treatment.
editor's note: Taking a sexual history is an important part of the evaluation of patients who are using antidepressant medication. All patients in this study, including placebo-treated subjects, reported improved sexual function at end point. The ability of the patients to talk about their symptoms at each visit may have done as much as medication to improve their sexual function.—b.a.