Sildenafil (Sildenafil), also known as a phosphodiesterase type 5 (PDE5) inhibitor, is used primarily for the treatment of erectile dysfunction (ED), but also for pulmonary hypertension. This drug is particularly well known under its brand name Viagra. Molecular structure of sildenafil The chemical formula of sildenafil is C₂₂₂H₃₀N₆O₄S and has the following characteristic chemical structure Sequence of actions Sildenafil is known to inhibit the activity of the PDE5 enzyme, which is abundant in penile tissue and is responsible for degrading cGMP (cyclic guanosine monophosphate). cGMP...

Tadalafil is a phosphodiesterase type 5 (PDE5) inhibitor, widely known by the brand name Cialis. It is used for the treatment of erectile dysfunction (ED) and also for the treatment of pulmonary hypertension. Molecular structure of tadalafil The chemical name for tadalafil is 1,2,3,4-tetrahydro-β-carboline-6-carboxamide, and its official chemical formula is C₂₂H₁₉N₃O₄. This molecule has several characteristic chemical structures: Molecular Mechanism of Action Tadalafil inhibits the PDE5 enzyme from degrading cGMP (cyclic guanosine monophosphate). cGMP aids erection by promoting smooth muscle relaxation and increasing blood flow,...