| Approximately 140 million males worldwide are estimated to suffer from impotence. Over than 50% of all males with ED are assumed to have some physical (medical) condition. The rest are thought to have psychological causes of impotence. Diabetes and circulatory, nerve damage or urological conditions are medical causes of erectile dysfunction.
Penile erection happens when the blood vessels delivering blood to the organ enhance the delivery of blood and the blood vessels carrying blood away from the penis decline the removal of blood. In healthy men, sexual arousal brings on the production and release of nitric oxide in the penis. Then, nitric oxide activates the enzyme - guanylate cyclase - which results in the production of cyclic guanosine monophosphate (cGMP). It is the cGMP that is mainly responsible for the erection by controlling the amount of blood is delivered and carried away from the penis.
Viagra is used for the treatment of impotence of either medical or psychogenic condition. Viagra inhibits an enzyme called phosphodiesterase-5 (PDE5) which destroys the cGMP. Hence, sildenafil precludes the destruction of cGMP and allows cGMP to increase in quantity and persist longer. The longer cGMP persists, the more prolonged the engorgement of the penis.
Viagra is speedily absorbed. Maximal observed plasma concentrations are reported within 30 to 120 minutes of oral dosing in the fasted state. When sildenafil is taken with a fatty meal, the rate of absorption becomes slower, with maximum concentration reported in an hour.
Sildenafil increases the effects of heart medicines and nitrates that are prescribed mainly for curing angina. Hence, drug interactions with cardiac medications and nitrates can be dangerous.
About 15% of people taking sildenafil have side effects. The most common side effects are bad headaches, dyspepsia, facial flushing and visual problems. Uncommon cases of sudden loss of hearing have been reported with phosphodiesterase inhibitors, such as sildenafil, sometimes with ringing in the ears and dizziness.
Before taking Viagra, consult your physician. If you are allowed to use Viagra, strictly follow the recommended dose. |
