Evaluation of the safety and efficacy of sildenafil citrate for erectile dysfunction in men with multiple sclerosis: a double-blind, placebo controlled, randomized study.

PURPOSE: We evaluated the safety and efficacy of sildenafil citrate for treating erectile dysfunction in patients with multiple sclerosis.

MATERIALS AND METHODS: A total of 203 patients with multiple sclerosis (age range 18 to 50 years old) with erectile dysfunction were randomly assigned to receive 50 to 100 mg sildenafil (102 patients in group 1) or a similar regimen of placebo (101 patients in group 2) 45 minutes to 2 hours before sexual stimulation. Patients were asked to use at least 24 doses/attempts at home. Primary outcome measures consisted of responses to questions 3 and 4 from the International Index of Erectile Function questionnaires well as responses to Sexual Encounter Profile diary questions 2 and 3. We also assessed the number of attempts at sexual intercourse, the number of attempts that were successful and adverse drug effects.

RESULTS: Improved erections (positive response to the Global Assessment Questionnaire) were reported by 32.8% of patients receiving sildenafil and 17.6% of those receiving placebo (p = 0.04). For Sexual Encounter Profile question 2 (successful penetration) the increase from baseline in mean per patient percentage of yes responses was 29.4% after sildenafil vs 18.8% after placebo (p = 0.04). The proportion of successful sexual attempts ranged from 12% to 26% for sildenafil and from 9% to 21% for placebo, respectively (p = 0.044). Of patients taking sildenafil and placebo 24 (23.5%) and 9 (8.9%) experienced 81 and 31 adverse events, respectively (p = 0.01).

CONCLUSIONS: Compared with placebo, sildenafil has little effect on multiple sclerosis emergent erectile dysfunction and, therefore, cannot be recommended for the routine treatment of erectile dysfunction in patients with multiple sclerosis. This finding implies that there must be other mechanisms that are not affected by sildenafil or are resistant to the effects of sildenafil.