Sildenafil, commonly sold under the brand name Viagra, is a phosphodiesterase type 5 (PDE5) inhibitor that is used for treating pulmonary arterial hypertension and erectile dysfunction and works by dilating and relaxing the blood vessels in the lungs. This results in the lowering of the lungs’ BP and helps improve stamina and agility. Sildenafil is an active ingredient in Viagra and its dose ranges from 25mg to 100mg per tablet.

How sildenafil works
Sildenafil protects the cGMP (cyclic guanosine monophosphate) from getting degraded by the cGMP-specific PDE5 in the mass of erectile tissues, wherein the nitric oxide binds itself to the guanylate cyclase receptors. This results in an augmented levels of the cGMP. These result in smooth relaxation of muscles, which also contributes positively to increased blood flow to the penis. This causes an erection. Sildenafil is a selective and potent inhibitor of the cGMP-specific PDE5 that are responsible for the cGMP degradation in the mass of erectile tissues. Sildenafil acts as a PDE5 binding agent, resulting in increased cGMP and longer and better erections.

Possible side-effects of sildenafil
As it is with most medicines, sildenafil could also cause unwanted side-effects, although not everyone experiences them. While the unwelcome effects often improve as the body adjusts to the new medicine, if the side-effects become troublesome or continuous, one should immediately consult a doctor or physician. Some of the very common side-effects of sildenafil that affect more than 1 in 10 men are:

• Headache: If one experiences a headache, they should ask their doctor or pharmacist to recommend a suitable painkiller.
• Blocked nose, indigestion, feeling sick or flushing: These are very common and will pass soon and do not require any medication.
• Visual changes or feeling dizzy: If one experiences visual changes such as color distortion or blurred vision, then one shouldn’t use machines and tools or drive or venture out on their own until their vision has returned to normal.
• Longer erections, vision problems and chest pain: This is extremely important; if the erection lasts for longer than 4 hours, or if one experiences sudden loss of vision or if one gets chest pains, then one should contact a doctor for medical attention immediately.

In extremely rare cases, when Viagra has been ingested with other illegal drugs or medications, a condition known as priapism’ could occur, which is a painful erection that lasts for longer than 4 hours. Not only is this serious and painful but it could also do long-lasting damage to the penis. In such cases, people should immediately seek medical help.