Papaverine Hydrochloride/Phentolamine Mesylate Injectable Formulation

**Semantic type:** Organic Chemical|Pharmacologic Substance

**Definition:** An injectable formulation composed of the hydrochloride (HCl) salt form of papaverine, an opiate alkaloid isolated from the plant Papaver somniferum and produced synthetically, and the mesylate salt form of phentolamine, a synthetic imidazoline and alpha-adrenergic antagonist, that can be used in the treatment of erectile dysfunction (ED). Upon injection of the papaverine HCl/phentolamine mesylate injectable formulation directly into the corpus cavernosum, the two active ingredients work synergistically. Papaverine non-selectively inhibits phosphodiesterases (PDE), increases cyclic adenosine monophosphate (cAMP) production, relaxes penile smooth muscles, causes vasodilation, and increases blood flow to the penis. This causes an erection. Phentolamine binds to and inhibits alpha-1 and alpha-2 adrenergic receptors, resulting in a decrease in peripheral vascular resistance, relaxes penile smooth muscles, causes vasodilatation, and increases blood flow to the penis, thereby simultaneously causing an erection.

**Synonyms:** - Bi-Mix - Bi-Mix - BiMix - Papaverine/Phentolamine Injectable Formulation