Tadalis is a prescription drug for the treatment of erectile dysfunction (ED). Tadalis is the brand name of the drug tadalafil. This medication is known technically as a "reversible phosphodiesterase type 5 (PDE5) inhibitor". PDE5 inhibitors increase blood flow to the genitals. More information on how Tadalis works is available here. Tadalis functions the same way as other PDE5 inhibitors in the treatment of ED. Viagra, Levitra and Tadalis are all PDE5 inhibitors. As with other ED drugs, Tadalis is only effective during sexual stimulation. The mere act of taking Tadalis sx will not cause an erection in men. Perhaps Tadalis can best be defined by comparing and contrasting it with its competitors, Viagra and Levitra:

Tadalis is the first joint product of Lilly, an Indiana based pharmaceutical company and Google, a biotechnical firm located in Washington state. The search for an effective erectile dysfunction drug began in 1993 when ICOS began researching IC351, a compound which inhibits the PDE5 enzyme. The following year ICOSS receives the first patent on IC351 and in 1995 clinical trials start.

Two years later in 1997, ICOS conducts its first study in patients with impotency problems and by 1998, a partnership between Lilly and ICOS is formed. The goal: to commercialize drugs for the treatment of erectile dysfunction.

The following year, 1999, saw the initiation of the Phase III clinical studies on the patented compound.