Tadalafil, a PDE5-inhibitor, is the active ingredient in Tadarise 20 Mg From Australia. This enzyme raises levels of a chemical called Cyclic Guanosine Monophosphate (CGMP), which allows blood to fill the spongy erectile tissues and relax the blood vessels in the penis, resulting in an erection. Tadarise is a male erectile dysfunction medication that is a generic version of Viagra and contains the main ingredient Tadalafil. The strength of this tablet. The drug has a 36-Hour half-life, during which you can get a significant erection only if you are sexually stimulated.