Drug company Pfizer issued a statement on May 27th regarding it's impotency drug Viagra.
Viagra, one of the company's best selling drugs is in the news following the release of results of a study which found that the drug caused sudden blindness in a small number of men.
Dr. Howard D. Pomeranz, from the University of Minnesota in Minneapolis, co-author of the study says they have known for years that some men who take Viagra may experience temporary color changes in their vision and see things as blue or green, but non-arteritic anterior ischemic optic neuropathy (NAION) is a much more serious condition because it can lead to permanent vision loss. Combined with past reports, this study brings the total number of sildenafil-related NAION cases to 14.
Pfizer say a review of 103 Viagra clinical trials involving 13,000 patients found no reports of NAION. The company say that outside of clinical trials, Viagra has been used by more than 23 million men worldwide over the past seven years and reports of visual field loss due to NAION are extremely rare. They say that there is no evidence showing that NAION occurred more frequently in men taking Viagra than men of similar age and health who did not take Viagra.
According to Pfizer, NAION is the most common acute optic nerve disease in adults over age 50 and it shares a number of common risk factors with erectile dysfunction: age over 50, high blood pressure, high cholesterol, diabetes. Most of the reported cases in which NAION has occurred in men taking Viagra have involved patients with underlying anatomic or vascular risk factors associated with the development of NAION.
Pfizer says it is in discussions with the Food and Drug Administration (FDA) to update the Viagra label to reflect these rare ocular occurrences, but maintains that Viagra has a strong safety profile and remains an effective medication that benefits millions of patients.
Viagra was initially intended to treat heart disease, but in trial studies, the penile erection enhancing effects were noticed. The drug was then patented in 1996, approved by the FDA in 1998 and was for sale in the United States later that year. As it was the first pill approved to treat erectile dysfunction in the United States it quickly became a huge success.
Viagra is supposedly only available by prescription from a doctor, but it was advertised directly to consumers on TV and a number of sites on the Internet offer Viagra for sale after an "online consultation," which is merely a web questionnaire. It is highly likely that many men and some women experiment with the drug to increase sexual prowess or pleasure, and annual sales of Viagra in the period 1999-2001 exceeded $1 billion.
The "Viagra" name has become so well known that many fake aphrodisiacs now call themselves "herbal Viagra" or are presented as blue tablets imitating the shape and colour of Pfizer's product. A mixture of Viagra and ecstasy, called sextasy, has become popular among rave partygoers and Viagra is also informally known as "Vitamin V".
The name "Viagra" is a marketing invention possibly inspired by the Sanskrit word "vyâghra", which means "tiger". The word rhymes with "Niagara"which is evocative of a sense of incredible erectile and ejaculatory strength, and the word itself implies vigor and virility.
The erection process involves the release of nitric oxide which ultimately leads to smooth muscle relaxation in the corpus cavernosum, resulting in increased inflow of blood and an erection.
With Viagra on board, normal sexual stimulation leads to better erections. Without sexual stimulation Viagra should not cause an erection.
Other drugs that operate by the same mechanism include Cialis and Levitra.
Priapism, severe hypotension, myocardial infarction, ventricular arrhythmias, sudden death, stroke and increased intraocular pressure are some of the serious adverse effects of Viagra.
An erection lasting for more than four hours is called a priapism, which requires immediate medical attention. Without attention, permament damage may occur to the penis, including the inability to obtain an erection or curvature.
Sneezing, headache, flushing, dyspepsia, prolonged erections, palpitations and photophobia, visual changes including blurring of vision and a curious bluish tinge are some of the common side effects reported. Some users complained of blurriness and some a loss of peripheral vision. It appears that there is a hereditary condition described as a "cup" in the retina that is the constant among all cases.
In conclusion taking Viagra may result in a serious medical condition but this is rare. It does however appear to carry quite a wide range of possible less serious side-effects.
Consult your physician before taking Viagra.
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