The substitution of Phentolamine with an equal amount of Chlopromazine as an alpha-blocker in vasoactive cocktails used for intracavernous injection therapy for the treatment of erectile dysfunction

Abstract

Introduction: This brief report describes the replacement of phentolamine mesylate with an equal amount of chlorpromazine HCl in vasoactive drug mixtures used as intracavernous (IC) injection therapy for treating erectile dysfunction (ED). Phentolamine, amongst other drugs, had been used in drug injection therapy for the treatment of ED, but was replaced as single drug therapy by more effective drugs, such as alprostadil (prostaglandin E1). It has, however, still widely been used as alpha-blocking agent in vasoactive drug cocktails. Phentolamine has a synergistic effect with alprostadil, papaverine and atropine in drug combination cocktails. These injection mixtures are very effective for treating ED and are commonly known as bimixtures, trimixtures and quadmixtures. The vasoactive drug, phentolamine, was withdrawn from the market in South Africa. Chlorpromazine (a phenothiazine) was suggested as an alternative alpha-blocking agent to be used in drug cocktails for the IC treatment of ED.

Methods: Three hundred and sixty-four (364) patients were questioned and evaluated during follow-up visits to an ED clinic after phentolamine mesylate was replaced with an equal amount of chlorpromazine HCL in their regular IC injection preparations. The collected data is based on results from self-administration at home.

Results: No significantly unusual adverse effects or altered efficacy of the new preparations were reported. The patients noted a change in the colour of the drug mixtures that contain chlorpromazine and papaverine. Despite this slight change in colour, the effectiveness of the mixtures remained the same if a use-before date of three months was adhered to.

Conclusion: The results indicate that phentolamine mesylate can effectively be replaced with an equal amount of chlorpromazine HCL in IC drug cocktails for the treatment of ED.