Sildenafil er en potent og selektiv hæmmer af cyklisk guanosinmonophosphat (cGMP) - specifik fosfodiesterase type 5 (PDE5), enzymet der er ansvarlig for nedbrydningen af cGMP.
Sildenafil is a potent and selective inhibitor of cyclic guanosine monophosphate (cGMP) specific phosphodiesterase type 5 (PDE5), the enzyme that is responsible for degradation of cGMP.