Sildenafil is one of the best oral ED medications available. It works by reducing the PDE5 protein level in your blood, improving the flow of blood to your penis. It also improves the strength of your penis muscles so you can get a hard erection for longer periods. It can last for up to 4-6 hours. 1. What is Fildena Professional 100 mg? Fildena 100 is a medication used to treat erectile...