Salvage of sildenafil failures with cabergoline: a randomized, double-blind, placebo-controlled study

Abstract

To evaluate the safety and efficacy of cabergoline in men with erectile dysfunction (ED) who did not respond to sildenafil. Four hundred two sildenafil nonresponders aged from 21 to 59 years were included in the study. Patients were randomly divided into group 1, those who received 0.5-1 mg cabergoline weekly for 6 months and group 2, who received placebo for the same period. They underwent preliminary assessment, including medical and sexual history, self-administered International Index of Erectile Function (IIEF) and intravaginal ejaculatory latency time (IVELT) evaluation. Standard biochemistry and hematological laboratory tests, and measurement of serum testosterone and prolactin levels were also carried out. When indicated, other tests were used to establish the diagnosis of vasculogenic and neurogenic ED, including penile color duplex Doppler ultrasonography, pudendal nerve conduction test and impaired sensory-evoked potentials studies. The efficacy of two treatments was assessed every 2 weeks during treatment, at the end of the study, using responses to IIEF, IVELT evaluation, mean intercourse satisfaction domain, mean weekly coitus episodes and adverse drug effects. The trial was completed by 370 (92%) men. Positive clinical results were seen in 31.2% of patients in the cabergoline group compared with 7.1% of patients in the placebo group (P=0.04). The mean weekly intercourse episodes increased from pretreatment values of 1.4 and 1.2 to 2.2 and 1.4, for cabergoline and placebo, respectively (P=0.04). Baseline mean intercourse satisfaction domain values of IIEF 10 and 11 reached to 15 and 10 at 6-month treatment in groups 1 and 2, respectively (P=0.04). The IVELT after cabergoline and placebo gradually increased from 98 and 101 s to approximately 242 and 116 s, respectively (P=0.001). More drug-related adverse effects occurred in cabergoline group and 12 (5.9%) had to discontinue treatment (P=0.001). Cabergoline is moderately effective salvage therapy for sildenafil nonresponse. Further studies with different dosages and treatment regimens are necessary to draw final conclusions on the efficacy of this drug in ED.