Objective: To study the effect of vasoactive intestinal polypeptide (VIP) and phentolamine mesylate (PM) on patients in whom previous intracavernosal therapy had failed.
Patients and method: 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).
Result: 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.
Conclusion: The combination of VIP and PM at the dose used was a safe and effective treatment in patients in whom other therapies had failed.