Hi, This site about Sildenafil citrate(Viagra)
Viagra was also the most highly publicised of the new so-called 'lifestyle drugs' – drugs taken by people who are not seriously ill in an attempt to improve the quality of their lives.
If you take any medicines that have nitrates in them (like nitroglycerin for chest pain)—every day or even once in a while—you should NOT take VIAGRA. Discuss your general health status with your doctor to ensure that you are healthy enough to engage in sexual activity. If you experience chest pain, nausea, or any other discomforts during sex, seek immediate medical help.
The most common side effects of VIAGRA are headache, facial flushing, and upset stomach. Less commonly, bluish vision, blurred vision, or sensitivity to light may briefly occur. In rare instances, men taking PDE5 inhibitors (oral erectile dysfunction medicines, including VIAGRA) reported a sudden decrease or loss of vision. It is not possible to sildenafildetermine whether these events are related directly to these medicines or to other factors. If you experience sudden decrease or loss of vision, stop taking PDE5 inhibitors, including VIAGRA, and call a doctor right away.
Although erections lasting for more than 4 hours may occur rarely with all ED treatments in this drug class, to avoid long-term injuries, it is important to seek immediate medical help.
If you are oltaking proteaseder than age 65, or have serious liver or kidney problems, your doctor may start you at the lowest dose (25 mg) of VIAGRA. If you are taking protease inhibitors, such as for the treatment of HIV, your doctor may recommend a 25-mg dose and may limit you to a maximum single dose of 25 mg of VIAGRA in a 48-hour period. If you have prostate problems or high blood pressure for which you take medicines called alpha-blockers, your doctor may start you on a lower dose of VIAGRA.
1. History
Sildenafil was synthesized by a group of pharmaceutical chemists working at Pfizer's Sandwich, Kent research facility. It was initially studied for use in hypertension (high blood pressure) and angina pectoris (a form of ischaemic cardiovascular disease). Phase I clinical trial`s under the direction of Ian Osterloh suggested that the drug had little effect on angina, but that it could induce marked penile erection`s. Pfizer therefore decided to market it for erectile dysfunction, rather than for angina. The drug was patented in 1996, approved for use in erectile dysfunction by the Food and Drug Administration on March 27, 1998, becoming the first pill approved to treat erectile dysfunction in the United States, and offered for sale in the United States later that year. It soon became a great success: annual sales of Viagra in the period 1999–2001 exceeded billion.
2. Mechanism of action
Part of the physiological process of erection involves the parasympathetic nervous system causing the release of nitric oxide (NO) in the corpus corpus cavernosum of the penis. NO binds to the receptors of the enzyme guanylate cyclase which results in increased levels of cyclic guanosine monophosphate (cGMP), leading to smooth muscle relaxation (vasodilation) in the corpus cavernosum, resulting in increased inflow of blood and an erection.
3. Disadvantages
FDA ALERT [7/2005]:
A small number of men have lost eyesight in one eye some time after taking Viagra, Cialis, or Levitra. This type of vision loss is called non-arteritic anterior ischemic optic neuropathy (NAION). NAION causes a sudden loss of eyesight because blood flow is blocked to the optic nerve.
4. If you want to buy Viagra
People always ask “Where's the best place to buy Viagra?” When i looking for diferent intenet bisneses, i investigated the top websites that sell Viagra(one of the best seller in internet) before we wrote this page. It's difficult to know what to look for in order to find legit Viagra websites.
You need to know that:
* More then half the Viagra sold on the internet is fake.
* Most of the websites that sell Viagra originate in 3rd world countries but they lie and pretend to be American or Canadian.
* There is no such thing as generic Viagra.
Things To Be Suspicious Of:
– You want to make sure there is a return address on the web site selling the Viagra. It should be a real address not a P.O. box. If there is no address that is a bad sign.
Why would someone want to hide their address? No address means that they are deliberately making it hard for you to track them down in case there is a problem.
– They should have a toll free telephone number. If something goes wrong you want to be able to speak to a real live person. It is very frustrating to be only able to communicate by e-mail when you have a problem
– Test the telephone number before you place your order. Ask the person who answers the phone where the product is shipped from. If they don't answer to your satisfaction, it's a bad sign.
– Ask them if they do the shipping and handling or if they only do the billing.
There is a good chance that the person on the other end of the phone is just a go-between; merely a clerk in front of a credit card machine, doing the billing for 100's of Viagra websites.
In many instances, they have no idea who the Viagra merchant is; all they know is that once a month they get a commission check from someone they have never seen or met in person.
Their job is answering the phone and ringing up your sale. After your credit card has been charged, the relationship is over.
– You get what you pay for. If it seems too good to be true, it probably is too good to be true. You are better off paying $10.00 per pill and getting the real thing than paying $6.00 per pill and getting a fake.
4.1. How Do They Do It?
Most of the Viagra selling websites are fly-by-night operations looking to make a quick buck. They often masquerade as Americans or Canadians but they are almost always located in 3rd world countries such as Cambodia or China.
You have to be real careful – oftentimes sites that originate from Russia or Nigeria are identity thieves looking to steal your credit card numbers. (You should never deal with a site from Russia or Nigeria, places where identity theft is common).
4.2. Viagra Official Web Site Information Regarding Fake Viagra
https://www.viagra.com/ – Official website; Geared to patients; all about Viagra and erections. Includes an offer for 6 free pills of Viagra.
http://www.viagramd.com/index.asp – Official Viagra website for healthcare professionals; How to start and maintain patients on Viagra, Multimedia presentation, prescribing information, etc.
5. Use of this medicine
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Sildenafil comes as a tablet to take by mouth. It should be taken as needed about 1 hour before sexual activity. However, sildenafil can be taken anytime from 4 hours to 30 minutes before sexual activity. Sildenafil usually should not be taken more than once every 24 hours. If you have certain health conditions or are taking certain medications, your doctor may tell you to take sildenafil less often. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take sildenafil exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.
Getting more info about Viagra :
http://en.wikipedia.org/wiki/Viagra
http://www.fda.gov/cder/consumerinfo/viagra/
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=PureSearch&db=PubMed&details_term=viagra – (from the National Library of medicine) automated Medline search; a listing of scientific papers in abstract form regarding Viagra.
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