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Viagra®
(sildenafil citrate)
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Cialis®
(tadalafil)
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Levitra®
(vardenafil)
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Maker: |
Pfizer (PFE) |
Eli Lilly & Co. (LLY) |
Bayer and GlaxoSmithKline (BAY
GSK) |
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Action: |
Viagra works by blocking the
enzyme that breaks down the substance that helps maintain erections.
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Cialis is available in 40 countries
and was approved by the FDA for distribution in the United States
in the end of 2003. Cialis functions by blocking an enzyme called
phosphodiesterase-5, or PDE-5 and allowing more blood to enter
the penis. |
Available in the U.S. since August,
2003, Levitra is an enzyme-blocker that helps increase
the blood flow to the penis. |
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Advantages: |
Viagra is the most widely known drug
used to treat impotence, with an estimated 70-80 percent of men
who take the little blue pill able to achieve and maintain an
erection. Manufacturer Pfizer reports that some men can get
an erection in as little as 14 minutes, but it generally takes
up to an hour to work and effectiveness lasts 4-6 hours. |
In impotence treatment, when a pill
starts to work and how long it lasts are key factors, doctors
say. According to trials, the almond-shaped yellow tablet takes
effect in as little as 15 minutes and lasts as long as a day-and-a-half.
A recent test by a German physician found that two-thirds of men
who took both Viagra and Cialis preferred Cialis because of the
duration of its effectiveness. |
The orange pill is speedier than Viagra,
its manufacturers claim, taking effect in as quickly as 15
minutes. On average, onset time is 25 minutes and can be effective
for 4-6 hours. The company also promises a 70 percent success
rate in patients with diseases such as diabetes or those who have
undergone prostrate cancer surgery-two common causes of erectile
dysfunction. Despite similar chemical structure, Levitra's makers
maintain it's not just a me-too drug. It isn't as affected by
fatty foods, so may be preferred for after dinner dates. It's
taken once a day, but a lower dosage is required, meaning there
may be fewer side effects. |
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Cautions: |
Skip the heavy meal as food interferes
with Viagra's absorption into the body. Because men take a larger
dosage of Viagra than its rivals, side effects -- including headaches,
flushing, blue-tinged vision and indigestion -- can be bothersome.
Men using drugs containing any form of nitrate (like nitroglycerin
for heart pain) should not use Viagra. A dangerous drop in
blood pressure could result. Viagra also should not be used within
4 hours of taking an alpha blocker, a drug for benign prostate
conditions that helps men urinate. |
Men taking nitrates for angina
should not use Cialis. Side effects include headaches, dizziness,
nasal congestion and indigestion. |
Like Viagra, Levitra is not suitable
for people taking nitrate drugs for angina, or alpha-blockers
taken for prostate problems. A dangerous drop in blood pressure
could result. |
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Price Comparisons: |
» Viagra
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» Cialis
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» Levitra
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» Full price comparison
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