Apomorphine sublingual as primary or secondary treatment for erectile dysfunction in patients with spinal cord injury

To evaluate the effectiveness of apomorphine sublingual (SL) 3 mg, as a primary or secondary treatment for erectile dysfunction (ED) in patients with spinal cord injury (SCI), and to determine possible differences in efficacy considering clinical, urodynamic and neurophysiological findings.

The study included 22 patients with chronic SCI and neurogenic ED who were examined physically and by a video-urodynamic evaluation. A neurophysiological evaluation included somatosensory evoked potentials of the pudendal nerve, palmar and plantar sympathetic skin responses and bulbocavernous reflex recordings. Thereafter the patients received 8 tablets of apomorphine SL 3 mg and were asked to complete the International Index of Erectile Function questionnaire before and after treatment. Side-effects, subjective efficacy compared with other treatments and satisfaction with the SL administration were recorded.

Of the 22 men, 11 had upper motor neurone lesions (six complete, five incomplete), eight lower motor neurone lesions (seven complete, one incomplete) and three had mixed lesions. In all, 12 patients took sildenafil citrate and five alprostadil intracavernosally beforehand, and five had used nothing to treat their ED. Seven patients had some response and reported that the drug helped them to obtain an erection, but only two reported erections sufficient for intercourse and would agree to continue apomorphine SL as their standard treatment; all the others reported being disappointed. Nine patients reported side-effects. There were no significant correlations for electrophysiological or urodynamic findings and treatment success. Of the 22 patients 20 preferred SL rather than the normal administration.

Apomorphine SL, a D1/D2 dopamine agonist, facilitates erectile function in a heterogeneous group of patients with no significant relationship with any of the assessed urodynamic or electrophysiological variables. The overall low rates of response either for primary or secondary treatment suggests that apomorphine will have limited applicability in patients with SCI.