Tadacip is a PDE5-inhibitor, which means, it inhibits the enzyme PDE5 (phosphodiesterase type five). Once PDE5 is suppressed, the body increases the levels of cyclic Guanosine Monophosphate and Nitric Oxide. These chemicals improve the blood flow throughout the system by relaxing the penile muscles and dilating the arteries. The tiny blood vessels in the erectile organ receive an adequate amount of blood to encourage the erection process that sustains for a longer duration.