Sildenafil, marketed under the trade name Viagra, is a potent cGMP-specific phosphodiesterase inhibitor that is highly selective for PDE5. While most notable for its use in the treatment of erectile dysfunction, sildenafil’s vasorelaxant properties have also been used to control vascular tone in pulmonary arterial hypertension and high-altitude pulmonary edema associated with altitude sickness. Thiosildenafil is a derivative of sildenafil that has been found as an adulterant in dietary supplements advertising sexual enhancement for men. The biological characteristics of thiosildenadil have not been reported.[Cayman Chemical]
