VIAGRABrian Louis

BASICS

Viagra is a brand name for the chemical sildenafil nitrate. Viagra is a drug made by the Pfizer corporation to treat “erectile dysfunction. It was approved by the FDA in 1998.

THE WAY IT WORKS

During arousal, action potentials activate nitric oxide synthase which produces nitric oxide. NO is released as a neurotransmitter and activates an enzyme that turns GTP to cGMP. CGMP relaxes smooth muscle cells around arteries in the penis allowing them to soften and expand. This allows blood to flow into the penis creating an erection. PDE5 is an enzyme released into the body that breaks down cGMP and turns it back into GTP. This causes constriction of blood flow and loss of erection. Viagra works by selectively inhibiting PDE5.

SIDE EFFECTS

Headache; flushing dizziness; can decrease blood pressure slightly; on rare occasions it inhibits PDE6 which can cause altered vision; on rarer occasions it inhibits PDE3 which can cause the heart to work harder in order to contract; the most dangerous effect is on old, out of shape people who don’t have the heart for the intense, prolonged physical exertion sometimes experienced during sex.

CONTRAINDICATIONS

Viagra is contraindicated with all nitrates as it can increase their effect dramatically. Viagra should not be taken by people with weak hearts.

ADMINISTRATION

Viagra is taken in 25, 50, or 100mg pills. On the internet a 100mg pill goes for about 10$ and a 50mg pill a little less.

ERECTILE DYSFUNCTION

The National Institute of Health says that ED is “the repeated inability to get or maintain an erectin firm enough for sexual intercourse.” The Pfizer web-sight says “if only once in a while a man can’t maintain an erection long enough to have satisfactory sex, that man has ED.” Pfizer also says ED can crush a man’s pride and put strain on a relationship. Pfizer claims that 50% of all men between 40-70 haveD, and that Pfizer has treated over 16 million men. I say the over-abundance of PDE-5 or lack of cGMP that can cause loss of erection could be caused by a number of things, one of which may be the human condition.

POPULARITY AND PFIZER

It’s estimated that about nine tablets of Viagra are dispensed every second worldwide.

Sensing the vagueness of ED, The National Health Service, soon after the introduction of viagra in 1998, advised that physicians restrict the amount of viagra they prescribe and gave specific recommendations on what should be diagnosed as ED. Pfizer immediately sued the federal government for trying to pressure physicians to not prescribe viagra. Pfizer lost the lawsuit, but the NHS did make their recommendations more lenient.

Viagra is very popular online. An estimated 10,000 sights advertise viagra and leading online pharmacies report on issuing hundreds of prescriptions a day. I get viagra ads in my e-mail. The way it works is you fill out a questionnaire online and a licensed physician reviews your answers. If he deems you worthy, viagra is sent in the mail. Many of the questionnaires are short and the judgemat of the physician can be shady. One study showed that three of ten doctors issued viagra to a pretend overweight woman with “orgasm problems”.

Pfizer now has a patent not only on Sildenafil, but also on the mechanism it uses to prolong erection. Specifically, it has a patent on the inhibition of PDE-5. This is the first time that a pharmaceutical company has patented a chemical process as opposed to simply patenting a chemical.

Bayer and Eli Lilly are both trying to market drugs that inhibit PDE-5. Pfizer is currently involved in lawsuits against Lilly and Bayer for patent infringement. The UK has dismissed the patent and thrown out similar lawsuits and the Eli Lilly drug Cilia (which works by the inhibition of PDE-5) is due to hit the European market this year. Pfizer asserts that it’s patent covers the use of all drugs that treat ED by inhibiting PDE-5.

This month the FDA allowed Pfizer to market Zoloft as a “social anxiety” treatment. Social anxiety disorder is defined by the social anxiety institute as “The fear and anxiety of being judged and evaluated negatively by other people.

For the last year and a half Pfizer has been moving closer to acquiring pharmacia for 60 billion dollars. The merger has been waiting on approval by the government, which is expected to come as soon as 2/28/03,

Pfizer owns Warner-Lambert, Parcke-Davis and Goedecke. Pfizer is probably soon to own Pharmacia which owns Sugen and Upjohn.