Sildenafil Citrate is an oral drug used for the treatment of Erectile Dysfunction (ED) and Pulmonary Arterial Hypertension (PAH) in men. It belongs to the class of drugs known as Phosphodiesterase Type 5 (PDE 5) inhibitors. The problem of ED makes a man unable to achieve or sustain an erection during sexual intercourse. Sildenafil Citrate helps to relax the muscles present in the walls of the blood vessels and increases blood flow to certain areas of the body. The enzyme PDE 5 causes a constriction in the arteries and does not let blood flow properly. For an erection to occur, the penis needs to be filled with blood. A molecule known as cGMP is responsible for the contraction and dilation of blood vessels. It carries blood to and from the penis. The enzyme PDE 5 stops the production of cGMP and does not let erection occur. Sildenafil Citrate blocks the action of PDE 5 and enables the production of cGMP. This allows blood flow easily to the penis. As more and more blood flows to the penis, an erection is achieved. However, it is to be kept in mind that this drug does not enhance sexual performance or give you orgasm. A person needs to be sexually stimulated for the drug to work properly. This medicine is sold under the brand name Viagra in various doses such as 50 mg, 100 mg, 120 mg, etc. Generic versions of this medicine include Cenforce, Suhagra, Caverta, Edegra, Aurogra, etc. Doctors recommend taking a single tablet of Sildenafil Citrate 1 hour before sexual intercourse. This is because it takes approximately 30 minutes to 1 hour for this drug to dissolve into your bloodstream completely. For best results, it is advised to consume the medicine on an empty stomach. The effects of this medicine last for 4-5 hours. Follow your doctor’s prescription carefully and read the instructions mentioned on the leaflet of the drug.