Sildenafil Citrate

What it is:
Sildenafil citrate, marketed under the trade names Viagra® and Revatio®, is a powerful vasodilator. It works by relaxing smooth muscle in blood vessels throughout the body which results in an increase in blood flow. Pfizer initially targeted the drug to treat male erectile dysfunction, but some PAH specialists prescribed the drug for off label use to their patients. Anecdotal evidence was positive for many patients prompting Pfizer to organize a number of clinical trials which would expand the use and increase the demand for it. The FDA approved Revatio® in June of 2005 to treat PAH.

How is it Administered:
The differences between Viagra® and Revatio® are mostly superficial. Viagra® is blue and diamond-shaped. Revatio® is round and white. The dosing is different, but chemically they are the same. Both are oral medications. For treatment of PAH, this drug - in whatever form your doctor prescribes it - must be taken at three or more times per day at equal intervals. It is important to take this drug as directed by your physician. You will probably begin at a low dose and be asked to build up to a target maintenance level.

Risks, Side Effects and Special Cautions:
When you are being evaluated as a candidate for this medication, your doctor will probably have you come into his office or clinic so that your blood pressure can be monitored. Revatio® will probably cause a drop in your systemic blood pressure so care will be taken to ensure your blood pressure does not drop to an unsafe level. If you feel dizzy at any time while you are taking this medication, you should notify your doctor.

It is very important that you take this medication as directed. If the drug is stopped abruptly, your PAH might rebound so if you have to stop taking Revatio®, you will want to wean yourself down much in the same way you were asked to begin.

If you become dizzy or nauseated, or have pain, numbness, or tingling in your chest, arms, neck, or jaw during stop and call your doctor right away. You could be having a serious side effect of Revatio®.

Benefits:
Some PAH patients demonstrate through six-minute walk tests and echo results, an increase in exercise tolerance and a reduction in PAH pressures due to the increase in blood flow through the body including the lungs.

Maintenance:
Like all medications, you should store this drug at room temperature in a dry environment.

Costs:
Now that Sildenafil citrate has been approved to treat PAH, your insurance company should cover the cost of your medication. For those of you with no drug coverage or a high co-payment, you may want to ask your physician if he or she can prescribe Viagra® as the price of Viagra® has dropped because of competition in the marketplace.

Summary:
Sildenafil Citrate (Revatio®) is one of a handful but every growing list of oral medications available approved to treat PAH. It is often prescribed in combination with another class of medication such as Tracleer or Sitaxsentan which are endothelin receptor antagonists.

Sources:
The information contained on this page was obtained from a number of reputable resources including the FDA website, drugs.com and chest review.
 

Recent items from the PHCentral Newsroom:

• Pulmonary Hypertension May Be Reversible With Viagra
  (HealthDay News) -- Patients with pulmonary hypertension and heart failure have stiffer arteries and reduced sensitivity to vasodilators compared with patients without hypertension, which can be reversed by sildenafil (Viagra), according to a study in the Aug. 11 issue of the Journal of the American College of Cardiology.
   
• Viagra Trial Is Halted
  (New York Times) -- The National Institutes of Health has stopped a trial of Viagra that was intended to see whether the drug could be used to treat pulmonary hypertension in patients with sickle cell disease. The trial was looking at the safety and effectiveness of sildenafil, sold by Pfizer under the brand names Revatio and Viagra, the National Heart, Lung, and Blood Institute said. But the trial was stopped when the drug was found to cause serious medical problems in sickle cell patients. The drug is approved for the treatment of pulmonary hypertension under the brand name Revatio, and patients ...
   
• For Additional Information Visit:
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• Pfizer
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• FDA Drug Search: For information about this drug and any other drug approved by the U.S. FDA - patient info sheets, label info, approval history etc.

August 2009 - Page reviewed and updated.

• Latest News
• February 23, 2010
• Sildenafil Helps Young Patients with Single-Ventricle Disease

• Heart function significantly improved in children and young adults with single-ventricle congenital heart disease who have had the Fontan operation after treatment with sildenafil, a drug used to treat erectile dysfunction and pulmonary hypertension, say researchers from The Children’s Hospital of Philadelphia.
   

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• December 18, 2009
• Sildenafil for Pulmonary Hypertension Increases Pain Crises in Sickle Cell Patients

• A study to see whether sildenafil would improve walk distance in patients with sickle cell anemia and pulmonary hypertension had to be stopped when it turned out the drug increased the risk of vaso-occlusive crises.

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• October 07, 2009
• Simvastatin and sildenafil combine to attenuate pulmonary hypertension

• Statins have been proposed to be a potential treatment for pulmonary arterial hypertension. If introduced into clinical practice, the statin would have to be used in conjunction with established therapy. We investigated the effects of combining simvastatin with a phosphodiesterase type-5 inhibitor, sildenafil, in the rat model of hypoxia-induced pulmonary hypertension.

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• October 06, 2009
• Viagra Could Prevent Unhealthy Heart Growth

• More research is being undertaken with the erectile dysfunction drug Viagra and it’s possible use in preventing both men and women from suffering from heart failure. It is already well known how the active ingredient of Viagra has a positive impact on widening arteries not only in the penile region but also around the hearts and lungs which helps those suffering from pulmonary arterial hypertension.

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