Vasoactive intestinal polypeptide and phentolamine mesylate administered by autoinjector in the treatment of patients with erectile dysfunction resistant to other intracavernosal agents.

Abstract

To study the effect of vasoactive intestinal polypeptide (VIP) and phentolamine mesylate (PM) on patients in whom previous intracavernosal therapy had failed. The study comprised 70 consecutive patients attending a clinic for erectile dysfunction, in whom previous therapy with intracavernosal prostaglandin-E1 (20 microg and papaverine (30 mg) combined with 1 mg PM had failed. They were given intracavernosal injections, initially with 25 microg VIP/1 mg PM (VIP1) and if unsuccessful, 25 microg VIP/2 mg PM (VIP2). Both VIP1 and VIP2 were administered using a pre-filled ready-to-use autoinjector fitted with a 29 G needle. The patients were diagnosed as having spinal cord lesion (eight), diabetes (21), ischaemic heart disease (12), hypertension (six), other diagnoses (nine), or idiopathic causes (14). Forty-seven (67%) of patients achieved erections sufficient for sexual intercourse (33 on VIP1 and 14 on VIP2), initially under clinical supervision and subsequently during home use. Minor side-effects were transient facial flushing in 37 (53%), truncal flushing in six (9%), bruising in 14 (20%) and pain from the injection needle in eight (11%). No patients reported priapism or other serious adverse events. The combination of VIP and PM at the dose used was a safe and effective treatment in patients in whom other therapies had failed.