desmethyl-sildenafil

Desmethyl-sildenafil, also known as N-desmethyl sildenafil or UK-103,320, is a major active metabolite of sildenafil. It is formed primarily in the liver through oxidative N-demethylation by the cytochrome P450 enzymes CYP3A4 and, to a lesser extent, CYP2C9. Desmethyl-sildenafil retains approximately 50% of the pharmacological activity of its parent compound, sildenafil, acting as a potent and selective phosphodiesterase type 5 (PDE5) inhibitor. By inhibiting PDE5, it prevents the breakdown of cyclic guanosine monophosphate (cGMP), thereby contributing to smooth muscle relaxation and vasodilation, which are the therapeutic effects observed with sildenafil. While not developed as a standalone drug, its activity is significant in the overall pharmacological profile of sildenafil.

Other names

N-Desmethyl Sildenafil