papaverine + phentolamine

**Papaverine + phentolamine** is a compounded combination drug consisting of papaverine (a nonxanthine phosphodiesterase inhibitor and direct smooth muscle relaxant) and phentolamine (a non-selective alpha-adrenergic antagonist). The combination is primarily used as an intracavernosal injection for the treatment of erectile dysfunction, particularly in patients who do not respond to oral phosphodiesterase type-5 inhibitors. **Papaverine** exerts its effect by inhibiting phosphodiesterase enzymes, increasing levels of intracellular cAMP and cGMP, leading to smooth muscle relaxation and vasodilation. **Phentolamine** acts as a competitive antagonist at alpha-1 and alpha-2 adrenergic receptors, resulting in further vasodilation by blocking vasoconstrictive sympathetic stimuli. The combination potentiates penile blood flow and facilitates erection by relaxing the cavernous smooth muscle and dilating penile arteries. This combination is less potent than the three-drug mixture (Tri-Mix), but is more efficacious than papaverine alone[6][7][11].

Other names

Bi-Mix