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Sildenafil Citrate (Viagra)

 

Sildenafil Citrate (generic Viagra) Review

brand name: Viagra
generic names: Sildenafil, Sildenafil citrate, Isosorbide dinitrate

How does it work?

Viagra tablets contain the active ingredient sildenafil, which is a medicine used in the treatment of erectile dysfunction (impotence). Sildenafil is called a phosphodiesterase type 5 inhibitor, and works by preventing the action of a chemical in the body called phosphodiesterase type 5.

An erection is produced via a complex chain of events, involving signals from the nervous system and the release of chemical messengers within the tissues of the penis. One of these chemical messengers is called cyclic GMP.

Cyclic GMP causes the blood vessels in the penis to widen by relaxing a thin layer of muscle found in the blood vessel walls. This allows more blood to enter the penis, which ultimately results in the penis becoming rigid and erect.

Cyclic GMP is normally broken down by another chemical in the body called phosphodiesterase type 5. Sildenafil works by preventing the action of phosphodiesterase type 5, thus stopping the breakdown of cyclic GMP. This means that the blood vessels are kept dilated for longer, improving blood flow to the penis and maintaining an erection.

As sildenafil enhances the actions of the chemical messengers responsible for producing an erection, it will only work once these messengers are present. This means that sexual stimulation is required for it to produce and maintain an erection. The dose should be taken approximately one hour before intended intercourse.

What is the most important information I should know about sildenafil?

Do not take sildenafil if you are also using a nitrate drug for chest pain or heart problems. This includes nitroglycerin (Nitrostat, Nitro-Bid, Nitro-Dur, Nitrolingual, and others), isosorbide dinitrate (Dilatrate-SR, Isordil, Sorbitrate). Nitrates are also found in some recreational drugs such as amyl nitrate or nitrite ("poppers"). Taking sildenafil with a nitrate medicine can cause a serious decrease in blood pressure, stroke, leading to fainting, or heart attack. If you become dizzy or nauseated, or have pain, numbness, or tingling in your chest, arms, neck, or jaw during sexual activity, stop and call your doctor right away. You could be having a serious side effect of sildenafil. Do not take sildenafil more than once a day. Allow 24 hours to pass between doses. Contact your doctor or seek emergency medical attention if your erection is painful or lasts longer than 4 hours. A prolonged erection (priapism) can damage the penis.

A small number of patients have had a sudden loss of eyesight after taking sildenafil. This type of vision loss is caused by decreased blood flow to the optic nerve of the eye. It is not clear whether sildenafil is the actual cause of such vision loss. Sudden vision loss with sildenafil use has occurred most often in people with heart disease, or certain pre-existing eye problems, high cholesterol, high blood pressure, diabetes, and in those who smoke or are over 50 years old.

Stop using sildenafil and get emergency medical help if you have sudden vision loss.

What side effects may I notice from taking sildenafil?

Side effects that you should report to your prescriber or health care professional as soon as possible:
•changes in vision such as blurred vision, eyes being more sensitive to light, or trouble telling the difference between blue and green objects or objects having a blue color tinge to them
•difficulty breathing, shortness of breath
•chest pain or palpitations
•prolonged erection (lasting longer than 4 hours)
•skin rash, loss of vision, itching

Side effects that usually do not require medical attention (report to your prescriber or health care professional if they continue or are bothersome):
•diarrhea
•dizziness
•flushing
•headache
•indigestion
•nasal congestion

Recommended dosage

Doses range from 25 milligrams to 100 milligrams, depending on the drug's effect. The usual dose is 50 milligrams. If you are over 65, have liver or kidney problems, or are taking erythromycin, ketoconazole, itraconazole, ritonavir, or saquinavir a dose of 25 milligrams may be sufficient. Your doctor will adjust the dosage if the drug is not working properly for you.

To avoid low blood pressure, do not take the 50-milligram or 100-milligram dose of Viagra (Sildenafil) within 4 hours of taking an alpha-blocking drug such as Cardura.

Take Viagra only before sexual activity. The manufacturer recommends a maximum of 1 dose per day (1 dose every 2 days for those taking ritonavir).

What is it used for?

• Impotence (erectile dysfunction)
  
  

Viagra (Sildenafil) is used for:

Treating sexual function problems in men, such as impotence or erectile dysfunction, and other conditions as determined by your doctor.

Viagra (Sildenafil) is a phosphodiesterase inhibitor. It works by helping the blood flow into the penis to achieve and maintain an erection.