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.
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. 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).
Sildenafil - Viagra Medical uses
Sexual dysfunction
The primary indication of sildenafil is treatment of erectile dysfunction (inability to sustain a satisfactory erection to complete intercourse). Its use is now one of the standard treatment for erectile dysfunction, including for men with diabetes mellitus.
Pulmonary hypertension
While sildenafil improves some markers of disease in people with pulmonary arterial hypertension, it does not appear to affect the risk of death or serious side effects as of 2014.
Antidepressant-associated sexual dysfunction
Tentative evidence suggests that sildenafil may help men who experience antidepressant-induced erectile dysfunction.
Altitude sickness
Sildenafil appears to improve some risk factors for high-altitude pulmonary edema but it is unclear whether or not it affects the rate of the condition itself as of 2008.
Sildenafil - Viagra Adverse effects
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. Some sildenafil users have complained of seeing everything tinted blue (cyanopsia). 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 and a number of studies have linked sildenafil use with non-arteritic anterior ischemic optic neuropathy.
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. 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.
Interactions
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. 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.
Contraindications
Contraindications include
1. Concomitant use of nitric oxide donors, organic nitrites and nitrates, such as:
- nitroglycerin
- isosorbide mononitrate
- isosorbide dinitrate
- sodium nitroprusside
- alkyl nitrites (commonly known as "poppers")
3. Known hypersensitivity to sildenafil
Sildenafil should not be used if sexual activity is inadvisable due to underlying cardiovascular risk factors (such as recent heart surgery, stroke or heart attack, etc.).
Sildenafil - Viagra Clinical data
Pronunciation
sil-den-ə-fil
Trade names
Viagra, Revatio, others
AHFS/Drugs.com
Monograph
MedlinePlus
a699015
License data
EU EMA: Viagra
US FDA: Sildenafil
Pregnancy category
AU: B1
US: B (No risk in non-human studies)
Routes of administration
By mouth (tablets), IV
ATC code
G04BE03 (WHO)
Sildenafil - Viagra source wikipedia
0 Response to "Sildenafil - Viagra"
Thank you for Relevant Comments in Health Blog