Apomorphine for the Treatment of Erectile Dysfunction: Systematic Review and Meta-Analysis

Sublingual apomorphine could be an option in patients with erectile dysfunction who cannot take phosphodiesterase type 5 inhibitors (e.g., using nitrates). We have completed a systematic review to evaluate the effects of sublingual apomorphine comparing with placebo for treating erectile dysfunction. The evidence searching process finished on 9 January 2019. We included nine randomized controlled trials (RCTs). Treatment length varied from 4 to 8 weeks and doses ranged from 2 to 6 mg. The percent of successful sexual intercourse attempts per ingested dose of apomorphine was evaluated in eight studies. All the studies found that apomorphine was better than placebo (6-27% more successful intercourse attempts than with placebo), but differences were not statistically significant in one study done in patients previously treated with radical prostatectomy. Regarding erectile function scores, three studies reported higher improvement on the erectile function scores for apomorphine. Differences with placebo were not clinically relevant in another two studies, one in which only diabetic patients were included and one in which only patients with radical prostatectomy were involved. Discontinuation of treatment due to adverse events was higher for apomorphine, particularly for higher doses. Available evidence suggests that sublingual apomorphine is more effective than placebo, except for patients previously treated with radical prostatectomy, and is generally well tolerated at doses of 2 or 3 mg. Nowadays, sublingual apomorphine is the only licensed oral drug for erectile dysfunction not absolutely contraindicated with nitrates use, and more RCTs should be performed to evaluate its effects and safety for treating ED.