A comparative, crossover study of the efficacy and safety of sildenafil and apomorphine in men with evidence of arteriogenic erectile dysfunction

The aim of the study was to establish and compare the efficacy and safety of sildenafil and apomorphine in men with arteriogenic erectile dysfunction (ED). In all, 43 men with ED and postinjection max penile systolic velocity <25 cm/s in repeated Doppler ultrasonography were included. Of these, 24 men started on apomorphine 2 mg and 19 on sildenafil 50 mg, the doses titrated up to 3 and 100 mg according to effectiveness and tolerability. Safety was evaluated according to adverse events (AEs) and patient withdrawal. Efficacy was the percentage of attempts resulting in erections firm enough for intercourse, based on event log data. The incidence of AEs with apomorphine 3 mg was higher than with sildenafil 100 mg. Two men on apomorphine 3 mg discontinued treatment due to AEs. The overall success rate of sildenafil was 63.7% compared to 32.1% of apomorphine (Pearson χ2, P<0.01). Of all men, 25 (58.1%) responded to sildenafil 50 mg without the need for dose increase, while only one responded to apomorphine 2 mg. The response to sildenafil 50 mg was age related (analysis of variance, p=0.04). Satisfaction was reported by 76.75 and 13.95% of patients for sildenafil and apomorphine, respectively, but 20.9% were not satisfied with any of the two drugs. In conclusion, this study provides clear evidence that sildenafil, even at 50 mg dose, is more effective than apomorphine 3 mg in men with arteriogenic ED. The fact that one out of five patients is not satisfied with the above-studied drugs shows that new oral agents need to be evaluated for the treatment of this disorder.