Viagra tablets are a medication used to treat erectile dysfunction (ED) in men. They contain the active ingredient sildenafil, which works by increasing blood flow to the penis, helping to achieve and maintain an erection. Viagra tablets should be taken orally about 30 minutes to an hour before sexual activity.

Viagra (sildenafil) works by relaxing the blood vessels in the penis, which allows more blood to flow into the area and helps to create and maintain an erection. Specifically, it inhibits the enzyme phosphodiesterase type 5 (PDE5), which breaks down cyclic guanosine monophosphate (cGMP), a chemical that is responsible for relaxing the smooth muscles in the penis and increasing blood flow. By blocking the action of PDE5, Viagra increases cGMP levels and enhances the effects of nitric oxide, a chemical that is naturally produced in the body and also helps to increase blood flow to the penis. However, sexual stimulation is still required in order for Viagra to work effectively.