Viagra, also known as sildenafil is a drug typically used to treat erectile dysfunction. Viagra can also be used to treat pulmonary arterial hypertension, which is a serious medical condition that is characterized by increased blood pressure within the lung’s arteries. You may have pulmonary arterial hypertension if you have shortness of breath, syncope, fatigue, chest pain, leg swelling, or a fast heartbeat. People with pulmonary arterial hypertension often have difficulty exercising and the condition typically appears gradually over a long period of time. The cause of this disease is unknown. Viagra was invented in 1998 by Andrew Bell, David Brown, and Nicholas Terrett while they were researching treatments for cardiovascular disorders. Sildenafil’s bioavailability is 41%, its protein binding is around 96%, it is metabolised in the liver, its elimination half-life is about three and a half hours, and its molecular formula is C22H30N6O4S, giving it a molar mass of about 474 grams per mol. Viagra is sometimes used to treat antidepressant-caused sexual dysfunction as well as Raynaud’s phenomenon.

Viagra is associated with a number of negative side effects, including headaches, flushing, indigestion, and nasal congestion. Blurred vision, blue-tinted vision (cyanopsia) or loss of peripheral vision are also common side effects. The FDA discovered in 2005 that use of Viagra can occasionally lead to permanent loss of vision. Many studies have shown a strong correlation between Viagra usage and non-arteritic anterior ischemic optic neuropathy. Less frequent side effects include prolonged erections, severe low blood pressure, myocardial infarction (heart attack), ventricular arrhythmias, stroke, increased intraocular pressure, and sudden hearing loss. If you experience one of these severe side effects, stop taking Viagra and call a doctor immediately. People who are taking protease inhibitors (HIV infection medicine) should not take Viagra more than once every 48 hours. Protease inhibitors inhibit the metabolism of Viagra, greatly increasing its potency to dangerous levels. The same applies for erhthromycin and cimetidine.

Viagra is occasionally purchased for recreational use, particularly among young adults who think it will enhance their sexual performance. No evidence suggests that this is the case and in fact, due to the frequency of counterfeits available on the market, taking Viagra may impair your performance. However, a strong placebo effect has been discovered. Viagra is often used to counteract the effects of other drugs,. Combining Viagra with amyl nitrite is dangerous and often fatal. Viagra has some popularity among those suffering from jet lag and athletes, although no studies have shown Viagra to be effective in either case.

Viagra can be purchased without a prescription. You can buy it online for about a dollar a pill or in person at most drug stores. Viagra is completely legal, but be careful to only buy from reputable sites.