Viagra medication is indicated for the treatment of erectile problems in men. The medication is not indicated for women and children. The generic name of Viagra is Sildenafil citrate, which belongs to selective inhibitors of cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase type 5 (PDE5).

The Viagra medication is produced in dosage form of tablets equivalent to 25 mg, 50 mg and 100 mg of Sildenafil to be taken orally when needed. Viagra 50 mg is the most common dose prescribed for patients when the therapy with Viagra is initiated. The lower or higher doses are prescribed based on the efficacy of the drug and individual state of health of a patient.

Physiologically erection process requires the production of nitric oxide in the corpus cavernosum when sexual stimulation occurs. This stimulates the release of the enzyme guanylate cyclase, and enlarges the levels of cyclic guanosine monophosphate (cGMP), creating easy muscle relaxation in the corpus cavernosum and providing blood supply.

Clinical studies have demonstrated that Sildenafil inhibits selectively PDE5. Sildenafil makes the effect of nitric oxide better by restricting phosphodiesterase type 5 (PDE5), known for its ability to diminish cGMP in the corpus cavernosum. Sildenafil helps to increase the level of cGMP in the corpus cavernosum when sexual stimulation occurs and causes release of nitric oxide. Sildenafil is ineffective when a person is not sexually aroused.