Tadalafil, the active ingredient in Vidalista 40mg, inhibits the enzyme PDE5, which normally breaks down a substance called cGMP. cGMP helps relax the smooth muscles in the blood vessels of the penis, allowing for better blood flow. This process makes it easier to get and maintain an erection when sexually aroused. Vidalista 40mg can work for up to 36 hours, providing a long window of time during which you can achieve an erection with sexual arousal. This long duration is one of the reasons Tadalafil is often referred to as the “weekend pill,” allowing for more spontaneity in sexual activity.