Tadasoft 40 mg is a medication used to treat erectile dysfunction (ED) in men. It contains tadalafil as its active ingredient, which is also found in Cialis. Tadasoft belongs to a class of medications called phosphodiesterase type 5 (PDE5) inhibitors. Tadalafil works by inhibiting the enzyme phosphodiesterase type 5 (PDE5), which regulates blood flow to the penis. By blocking PDE5, tadalafil increases blood flow to the penis during sexual stimulation, resulting in an erection.