Apcalis is used to treat men who have impotence. Like Viagra, this pill is very easy to use, however it is more effective and has less side effects in comparison to Viagra (Sildenafil Citrate). It remains effective 24 to 36 hours after taking the tablet and for this reason it has been known as a 'Weekend tablet'. It improves the stamina of the impotent to hold on the stiffness of male reproductive organ by providing the adequate amount of the blood to the male reproductive system. Its key ingredient is Tadalafil that helps in the process of impotency curing.