Comparative cross-over study of sildenafil and apomorphine for treating erectile dysfunction.

Objective: To compare the effectiveness, safety and tolerability of sildenafil and apomorphine in Brazilian patients with erectile dysfunction (ED) of various causes.

Patients And Methods: In all, 108 patients (mean age 55 years, sd 11) and documented ED for > or =6 months were included in 12 centres in Brazil. The patients were initially followed for 2 weeks and then randomized to initial treatment with apomorphine or sildenafil, taken before sexual intercourse, no more than once a day. The initial dose (2 mg apomorphine and 50 mg sildenafil) could be adjusted (to 3 mg apomorphine, or to 25 or 100 mg for sildenafil) depending on the effectiveness and tolerability during the first 4 weeks of treatment. The patients were re-evaluated after 8 weeks on treatment and, after a wash-out period of 2 weeks (no treatment), received the other study drug (other than that received in the first phase), and then had the same procedures as in the first phase.

Results: In all, 97 patients were evaluated for therapeutic effectiveness, the overall effectiveness being assessed using two questions; sildenafil had a significantly higher proportion of affirmative answers for both (P < 0.001). Likewise, the estimates for the mean (sd) proportion of successful sexual intercourse, of 83.3 (4.7)% vs 40.3 (4.7)% and the total ED Inventory of Treatment Satisfaction score, of 86.7 (2.9) vs 56.9 (2.9) (P < 0.001) were higher for sildenafil. At the end of the study, 93.8% of the patients randomized to initial therapy with apomorphine declared a preference for sildenafil, and 81.3% of those initially treated with sildenafil declared a preference for that drug. The two drugs were well tolerated, and the main adverse events for apomorphine were nausea, vomiting, headache, taste perversion and dizziness; for sildenafil they were headache, flushing or vasodilatation, abdominal pain or dyspepsia and nasal congestion.

Conclusions: Sildenafil is more effective than apomorphine for treating ED, in the domains of erectile function, satisfaction with sexual intercourse and overall satisfaction, and was the drug preferred by most of the patients.