• One in 10 men in the world have erectile dysfunction.
• 30 million men in the United States have erectile dysfunction.
• 50% of men with diabetes have erectile dysfunction, frequently within 10 years of diagnosis.
• The likelihood of erectile dysfunction increases with age: 39% at age 40, 65% over the age of 65.
• Smokers have a higher likelihood of erectile dysfunction. Men who smoke more than 1 pack per day have a 50% higher chance of impotency than nonsmokers the same age.

Source: Minnesota Men’s Health Center. Erectile dysfunction statistics. Available at: www.mmhc-online.com.

The most important thing a patient must ask to our doctor is, simply, if Viagra is rigt for him or her. In this way, the patient will help the doctor to do a good diagnosis. To do this, he/she has to do a routine checkup, assessing the general health of the patient (it is indispensable to test the blood pressure). After that and before Viagra is prescribed, it is highly recommended to make some questions to the doctor:

• Every so often, I have a problem getting an erection. What does this mean?
• I want to try VIAGRA, but is it safe for me?
• I heard that with age, sex slows down. Is this true?
• Could a medication I’m taking affect my sexual performance?

Only then the doctor will be sure to prescribe the patient Viagra and the patient will be confident enough to take it.

The dosage for pulmonary arterial hypertension (Revatio) is one 20 mg tablet three times a day. Revatio pills are white, round, film-coated tablets imprinted with “RVT 20″ on one side and “Pfizer” on the other.

Source: wikipedia.org

Viagra can also have side effects on people havind drugs like nitroglycerin. As Viagra, Nitroglycerin works by increasing nitric oxide, opening up the arteries that supply the heart with oxygen. Taking nitroglycerin and Viagra together, plus the blocking of PDE5, can lead to an overincrease of the nitric oxide, what could mean problems.

Other problems with Viagra can include headaches, facial flushing and upset stomach. The possibility of heart attacks is one reason why Viagra is a prescription drug. This is why before being prescribed Viagra, patients must be asessed by their doctor, who needs firstly to understand their medical history.

Sources:

http://www.howstuffworks.com/

http://www.viagra.com/

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.

As with any ED tablet, in the rare event of an erection lasting more than 4 hours, seek immediate medical help to avoid long-term injury.

If you are older 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.

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 determine 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.

Sudden decrease or loss of hearing has been rarely reported in people taking PDE5 inhibitors, including VIAGRA. It is not possible to determine whether these events are related directly to the PDE5 inhibitors or to other factors. If you experience sudden decrease or loss of hearing, stop taking VIAGRA and contact a doctor right away.

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.

VIAGRA does not protect against sexually transmitted diseases, including HIV.

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.

Erectile Dysfunction isn’t the same for all men. Some men aren’t able to get an erection at all. Others can get one, but it’s not hard enough for sex. And others get a hard erection but lose it before or during sex. When a man has ED, the nerves or blood vessels in the penis don’t work properly. This prevents blood from flowing to the penis. And that can prevent an erection. Among the common causes, there is high blood pressure, high cholesterol, heart disease, diabetes or prostate problems. Depression, spinal injury, stress, smoking and alcohol or certain medicines can also cause erectile dysfunction.

Sources:

www.viagra.com

wikipedia.org

The mechanism that the body uses to “open a valve” in any part of the body involves four steps:

1. The brain sends a signal down a particular nerve fiber. This nerve fiber ends in an NANC nerve cell in an artery, somewhere near the point where blood flow needs to change. NANC stands for nonadrenergic-noncholinergic, and what it means is that the NANC nerve cell is able to create nitric oxide.
2. The NANC nerve endings inject nitric oxide into the blood and surrounding cells.
3. The nitric oxide stimulates an enzyme called guanylate cyclase in nearby cells, and this enzyme starts producing a chemical called cyclic guanosine monophosphate (cGMP).
4. cGMP tells smooth muscles that line an artery to relax. When they relax, blood flow increases.

This is the mechanism the brain uses to increase blood flow in several different parts of the body. So when the brain gets aroused, it sends a signal to the penis. Nerve cells in the penis’ corpora cavernosa start producing nitric oxide, leading to the creation of cGMP, which causes arteries in the corpora cavernosa to dilate, causing blood to flow into the penis. The extra blood flowing in causes the penis to inflate like a balloon. And then, the erection occurs.

Source: http://health.howstuffworks.com/

In the US, Viagra is available via prescription only. Pfizer still control the production and distribution of Viagra in the US, so in essence they can control this price to maximise profit and to recoup the cost of development. But in certain countries (e.g.: India and Mexico), the patent on Sildenafil citrate expired, what comes to mean that it can be manufactured very cheaply. Pharmacy websites have sprung up to act as a channel for distribution, likely operating outside of the USA, and roughly charging in the region of $2 per pill. So this mode of distribution has become in the last years the most popular way to buy Viagra online.

With this profit comes great competition, however, so off-shore pharmacy sites have resorted to one of the best popular forms of product marketing on the internet, affiliation. With massive profit margins to fall back on, pharmacy companies can easily offer commission rates of around 40% to their affiliates, ideally suited to spam as they are legally separated from the online pharmacy. So the onus there falls to the likely hid behind false identities and proxy servers.

The spammers that send all these Viagra message use sophisticated techniques to penetrate through all modern spam filters:

1. The spam is send as a GIF image, so spam filters that use text filtering won’t be able to detect it.
2. The spam messages are modified every day, including the ad design, the domain of the Web site, and even the price of the Viagra pills is changed frequently…
3. In some spam message, the text is written in italic, to avoid detection by OCR spam filters.
4. The spammers also add some “noise” (In a form of dots, lines and other shapes) to the spam image.
5. The spammers intentionally misspell commonly-filtered words or insert other characters. In the case of Viagra spam, it is very usual to find the word spelled as V1agra, Via’gra, Vi@graa, Vi*gra.

This is the way zombie computers and robots send us billions of spam a year to our mails. Viagra spam has been bothering us for 10 years, since the medicine was released in 1998. The spam is also called junk mail or UBE (Unsolicited Bulk E-mail).

Sources:

The Viagra Spam collection. http://www.nirsoft.net/articles/spam/viagra_spam.html

Modern life: How Viagra spam works. http://www.modernlifeisrubbish.co.uk/article/how-viagra-spam-works

Sildenafil. http://en.wikipedia.org/wiki/Viagra

Nowadays Viagra is the main treatment to fight erectile dysfunction, along with CIALIS (tadalafil) and Levitra (Vardenafil HCI), its primary competitors on the markets since it came out in 1998. Despite Viagra is basically used to treat erectile dysfunction, is also effective in the rare disease pulmonary arterial hypertension (PAH), relaxing the arterial wall and leading to decreased pulmonary arterial resistance and pressure. Sildenafil is also useful for the prevention and treatment of High altitude pulmonary edema associated with altitude sickness