what kind if drug is Viagra? Is it pill or cream? Is it safe to use it permanently?

Answer 1

Sildenafil citrate, sold under the names Viagra, Revatio and generically under various other names, is a drug used to treat male erectile dysfunction (impotence) and pulmonary arterial hypertension (PAH), developed by the pharmaceutical company Pfizer. Viagra pills are blue and diamond-shaped with the words "Pfizer" on one side, and "VGR xx" (where xx stands for "25", "50" or "100", the dose of that pill in milligrams) on the other. Its primary competitors on the market are tadalafil (Cialis), and vardenafil (Levitra).[edit] History
Sildenafil (compound UK-92,480) 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 trials under the direction of Ian Osterloh suggested that the drug had little effect on angina, but that it could induce marked penile erections.[1][2] 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.[3] It soon became a great success: annual sales of Viagra in the period 1999–2001 exceeded $1 billion.

The British press portrayed Peter Dunn and Albert Wood as the inventors of the drug, a claim which Pfizer disputes.[4] Their names are on the manufacturing patent application drug, but Pfizer claims this is only for convenience.


Viagra is available as blue pills with a characteristic shapeEven though sildenafil is only available by prescription from a doctor, it was advertised directly to consumers on US TV (famously being endorsed by Bob Dole and Football star Pele). Numerous sites on the Internet offer Viagra for sale after an "online consultation", a mere web questionnaire. 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. Viagra is also informally known as "Vitamin V", "the Blue Pill", as well as various other nicknames.

Pfizer's worldwide patents on sildenafil citrate will expire in 2011–2013. The UK patent held by Pfizer on the use of PDE5 inhibitors (see below) as treatment of impotence was invalidated in 2000 because of obviousness; this decision was upheld on appeal in 2002.


[edit] 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 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.

Sildenafil is a potent and selective inhibitor of cGMP specific phosphodiesterase type 5 (PDE5) which is responsible for degradation of cGMP in the corpus cavernosum. The molecular structure of sildenafil is similar to that of cGMP and acts as a competitive binding agent of PDE5 in the corpus cavernosum, resulting in more cGMP and better erections. Without sexual stimulation, and therefore lack of activation of the NO/cGMP system, sildenafil should not cause an erection. Other drugs that operate by the same mechanism include tadalafil (Cialis®) and vardenafil (Levitra®).

Sildenafil is metabolised by hepatic enzymes and excreted by both the liver and kidneys. If taken with a high-fat meal, there may be a delay in absorption of sildenafil and the peak effect might be reduced slightly as the plasma concentration will be lowered.


[edit] Dosage and price
As with all prescription drugs, proper dosage is at the discretion of a licensed medical doctor. The dose of sildenafil is 25 mg to 100 mg taken once per day between 30 minutes and 4 hours prior to sexual intercourse.

It is usually recommended to start with a dosage of 50 mg and then lower or raise the dosage as appropriate. The drug is sold in three dosages (25, 50, and 100 mg), all three costing about US$10 per pill. Name-brand Viagra sildenafil is not scored and a fairly hard coating makes it more difficult to accurately cut the pills in half, even with a pill cutter.


[edit] Contraindications
Contraindications include:

When taking nitric oxide donors, organic nitrites and nitrates, such as glyceryl trinitrate, sodium nitroprusside, amyl nitrite ("poppers")[5]
In men for whom sexual intercourse is inadvisable due to cardiovascular risk factors
Severe hepatic impairment (decreased liver function)
Severe impairment in renal function
Hypotension (low blood pressure)
Recent stroke or heart attack
Hereditary degenerative retinal disorders (including genetic disorders of retinal phosphodiesterases)

[edit] Side effects
Amongst sildenafil's serious adverse effects are: priapism, severe hypotension, myocardial infarction, ventricular arrhythmias, sudden death, stroke and increased intraocular pressure.

Common side effects include sneezing, headache, flushing, dyspepsia, prolonged erections, palpitations and photophobia. Visual changes including blurring of vision and a curious bluish tinge have also been reported.

Care should be exercised by patients who are also taking Protease inhibitors for the treatment of HIV. Protease inhibitors inhibit the metabolism of sildenafil, effectively multiplying the plasma levels of sildenafil, increasing the incidence and severity of side-effects. It is recommended that patients using protease inhibitors limit their use of sildenafil to no more than one 25-mg dose every 48 hours.

Some sildenafil users have complained of blurriness and loss of peripheral vision. In May of 2005, the U.S. Food and Drug Administration found that sildenafil could lead to vision impairment[6] and a number of studies have linked sildenafil use with nonarteritic anterior ischemic optic neuropathy.[7][8][9][10][11][12]

When used with an alpha blocker, take them at least four hours apart to avoid hypotension.[13]


[edit] Other uses

[edit] Pulmonary hypertension
As well as erectile dysfunction, sildenafil citrate is also effective in the rare disease pulmonary arterial hypertension (PAH). It relaxes the arterial wall, leading to decreased pulmonary arterial resistance and pressure. This in turn reduces the workload of the right atrium of the heart and improves symptoms of right-sided heart failure. Because PDE-5 is primarily distributed within the arterial wall smooth muscle of the lungs and penis, sildenafil acts selectively in both these areas without inducing vasodilation in other areas of the body. Pfizer submitted an additional registration for sildenafil to the FDA, and sildenafil was approved for this indication in June 2005. The preparation is named Revatio, to avoid confusion with Viagra, and the 20 milligram tablets are white and round. Sildenafil joins bosentan and prostacyclin-based therapies for this condition.[14]


[edit] Raynaud's phenomenon
In 2005, Dr. Roland Fries and colleagues reported that sildenafil cut the frequency of Raynaud's phenomenon attacks, reduced their duration by roughly one half, and more than quadrupled the mean capillary blood velocity. This was a double-blind, placebo-controlled crossover trial and the patients had both the primary and secondary forms and had all discontinued the more conventional treatments for this.[15]


[edit] Non-medical use

[edit] Aphrodisiac
Sildenafil is commonly and increasingly used as an aphrodisiac. While there is no clinical evidence that it has aphrodisiac activity, many seem to believe it will improve sexual performance as well as erectile function and enhance the sexual experience that will occur.


[edit] Recreational use
Viagra's popularity with young adults has increased over the years.[16] It is sometimes used recreationally. Some users mix Viagra with methylenedioxymethamphetamine (MDMA, ecstasy) in an attempt to compensate for the side effect common to many amphetamines of erectile dysfunction, a combination known as "sextasy", "rockin' and rollin', or 'trail mix'."

Answer 2

1

Answer 3

See PDE5 Inhibitors, they Elevate the Action of the Second Messager cGMP (By Decreasing it's Catabolism), Viagra has a Much Shorter Duration of Action than Cialis. A Pill. I don't Know What the Long-Term Effects Would Be, but Suspect it Will Exacerbate Asthma, Mast Cell Degranulation is Dependent On cGMP Levels.

Answer 4

Viagra is a drug classified to help people with erectile dysfunction. It helps to dilate the blood vessels of the male genitalia which increases blood supply and therefore aids erection. It is taken an hour before sexual intercourse. Researches suggests that because of its vasodilatory effects, it is also widely used to treat pulmonary hypertension of late. Pulmonary hypertension, being the condition which shows narrowing of the pulmonary artery causing increasing shortness of breath. This may be one of the reasons why we might find women using viagra as well. Dilates the pilmonary artery therefore relieves shortness of breath.

It is a diamond-shape blue pill.

It can be used long termed. But the use of viagra should be under the prescription of a medical expert otherwise serious complications can occur, especially to those individuals who are suffering to conditions which viagra is contra-indicated.

Answer 5

Viagra and Cialis are "pills" you take to increase the blood flow to the penis, thus allowing an erection. It's prescribed by a physician after a short physical to make sure you don't have heart problems that could be increased by the drug, there are contra indicators, as with any drug. It's generally safe as long as you take it per the directions of your physician.

Answer 6

Viagra is a pill, and I wouldn't suggest you use it permanently, unless you a doctors says it's okay. Oh, and viagra is suppose to help a man get an erection or last longer during sex.

Answer 7

I have found Viagra as the saver of my sexual life, my wife is now a satisfied woman. For better results I take the pill about 60-90 minutes before going to bed, it works perfect for me.
Viagra is good for me because i don't suffer any strong side effects like other men do. The only thing I get sometimes is a mild headache.
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Answer 8

Viagra not working? Then come to the National Revival Centre and get Fired Up! For times check the Kingdom Faith website:

Answer 9

iagra Soft Tabs give the same pharmacological effect in men’s body like Viagra normal pills. The mode of action of Viagra Soft includes several chemical actions that result in improvement of the blood flow in the male genital region. This occurs due to the vasodilatation of the blood vessels of the penis. The dilated blood vessels of the penis facilitate more blood coming to the male genital organ.In the physiological point of view, the penis becomes erect if a man is sexually aroused and the nitric oxides (NO) are released in the corpus cavernosum (spongy tissue) of the penis. Nitric oxide is the main chemical agent which involved in the activation of cyclic guanosine monophosphate (cGMP), and it influences the smooth muscle dilatation. Sildenafil is responsible to contribuite the cGMPin higher amount by pausing action ofphosphodiesterase type 5 (PDE5). The enzyme PDE-5 in higher concentration affects the concentration of cGMP in the penis and causes the erection problem. The PDE5 inhibition leads to relaxation of the smooth muscle and improve the blood flow to the penis. So the Viagra soft tabs have the faster effect and provide a strong and satisfactory erection. It comes in tablets soft tablets, Jelly and many more. for more information you can visit topdrugmart.

Answer 10

2

Answer 11

Viagra is a blue pill and exist in three doses :25mg, 50mg, and 100mg.
For the second part of the question it is best you consult your doctor who will do the appropriate physical examination and tests.Based upon these results you will be advised the exact dosage,the frquency and the duration you can take it.