Erectile dysfunctioning and impotency can ruin a man’s life, his marriage and can take away his respect. Pills like Viagra has been a blessing in disguise as it has proven to be lifesaver for some of the men. These pills increase the inflow of blood towards penis which helps men in gaining an unprecedented erection and perform better in bed.
Sildenafil, sold as the brand name Viagra among others, is a medication used to treat erectile dysfunction and pulmonary arterial hypertension.[3] Its effectiveness for treating sexual dysfunction in women has not been demonstrated.[3]
Common side effects include headaches and heartburn, as well as flushed skin. Caution is advised in those who have cardiovascular disease. Rare but serious side effects include prolonged erections, which can lead to damage to the penis, and sudden-onset hearing loss. Sildenafil should not be taken by people who take nitrates such as nitroglycerin (glycerin trinitrate), as this may result in a severe and potentially fatal drop in blood pressure.[3]
Sildenafil acts by inhibiting cGMP-specific phosphodiesterase type 5(phosphodiesterase 5, PDE5), an enzyme that promotes degradation of cGMP, which regulates blood flow in the penis.
Pfizer scientists Andrew Bell, David Brown, and Nicholas Terrett originally discovered sildenafil as a treatment for various cardiovascular disorders.[4][5] Since becoming available in 1998, sildenafil has been a common treatment for erectile dysfunction; its primary competitors are tadalafil(trade name Cialis) and vardenafil (Levitra).
In clinical trials, the most common adverse effects of sildenafil use included headache, flushing, indigestion, nasal congestion, and impaired vision, including photophobia and blurred vision.[2] Some sildenafil users have complained of seeing everything tinted blue (cyanopsia).[12] Some complained of blurriness and loss of peripheral vision. In July 2005, the FDA found that sildenafil could lead to vision impairment in rare cases[13]and a number of studies have linked sildenafil use with non-arteritic anterior ischemic optic neuropathy.[14]
Rare but serious adverse effects found through postmarketing surveillance include prolonged erections, severe low blood pressure, myocardial infarction (heart attack), ventricular arrhythmias, stroke, increased intraocular pressure, and sudden hearing loss.[2] In October 2007, the FDA announced that the labeling for all PDE5 inhibitors, including sildenafil, required a more prominent warning of the potential risk of sudden hearing loss.[15]
Care should be exercised by people who are also taking protease inhibitors for the treatment of HIV infection. Protease inhibitors inhibit the metabolism of sildenafil, effectively multiplying the plasma levels of sildenafil, increasing the incidence and severity of side effects. Those using protease inhibitors are recommended to limit their use of sildenafil to no more than one 25 mg dose every 48 hours.[2] Other drugs that interfere with the metabolism of sildenafil include erythromycin and cimetidine, both of which can also lead to prolonged plasma half-life levels.
The use of sildenafil and an α1 blocker (typically prescribed for hypertension or for urologic conditions, such as benign prostatic hypertrophy) at the same time may lead to low blood pressure, but this effect does not occur if they are taken at least 4 hours apart