Efficacy and safety of daily intake of apomorphine SL in men affected by erectile dysfunction and mild hyperprolactinemia: a prospective, open-label, pilot study.

Objectives: To evaluate the efficacy of the "daily" use of apomorphine SL compared with the "on demand" administration of the drug in patients with mild to moderate erectile dysfunction (ED) and mild hyperprolactinemia who were nonresponders to apomorphine administered "on demand."

Methods: In this open-label prospective study, 34 patients with mild-to-moderate ED and mild hyperprolactinemia were screened. The subjects answered the International Index of Erectile Function (IIEF) questionnaire and underwent follicle-stimulating hormone, luteinizing hormone, testosterone, free testosterone, and prolactin plasma testing, and Doppler sonography at the 2-week screening period to define the ED severity and etiology, at the end of a 4-week "as required" dose-escalation regimen of 2 mg/3 mg apomorphine SL, and at the end of a 4-week period of daily administration of the drug to assess the efficacy of each treatment modality.

Results: Twenty patients (age range 27 to 46 years) were included in the study. Eighteen subjects completed the 4-week "as required" drug intake period, and three (16.7%) benefited from this modality of treatment (P <0.05). Fifteen nonresponder patients participated in the 4-week daily apomorphine SL use, and 13 (86%) reported satisfaction with the treatment (P <0.05). The 3-mg daily administration was more effective than the 2-mg daily administration for erectile function (P <0.02) but not for other sexual domains scored with IIEF. Adverse events were of mild or moderate severity, either during the "as required" drug intake (4 patients) or during daily use (3 subjects) and were mainly nausea, dizziness, or headache.

Conclusions: Data from the clinical evaluation of symptomatic apomorphine SL use have always shown a poor success rate, probably because it is used "as sildenafil." Using apomorphine SL as a treatment of ED, we observed a significant improvement in both subjective and objective aspects scored with the IIEF. The increase of prolactin could influence the erective mechanisms, and it cannot be excluded that a subgroup of men with ED may have an impairment of central dopaminergic function. Moreover, additional studies need to define the daily use of apomorphine SL in large subgroups of men on the basis of ED etiology and severity.