Viagra May Help Muscular Dystrophy Patients

Study Suggests Erectile-Dysfunction Drug May Boost Circulation, Help Heart
By COURTNEY HUTCHISON, ABC News Medical Unit
Oct. 19, 2010

Though young boys may seem like unlikely candidates for treatment with Viagra, new research in mice suggests that the drug -- usually prescribed for erectile dysfunction -- may one day be used to minimize heart problems for pre-teen and adolescent boys with Duchenne muscular dystrophy.

Since Viagra (sildenafil) was approved for erectile dysfunction in 1998, researchers have identified a number of other conditions that benefit from the famed "little blue pill," such as pulmonary hypertension, heart problems in severely premature infants, and decreased circulation in patients with gangrene. New research suggests it might even help treat prostate cancer.

Now Viagra has the potential to become a heart helper for young boys who are just beginning to suffer from cardiac degeneration due to Duchenne muscular dystrophy (DMD).

Viagra as Double-Duty Drug

Clinical trials are in process to test Viagra in older boys with DMD, but Froehner says his team hopes to test this treatment on younger boys aged 8 to 12 who do not yet show clinically significant heart problems. He says the dosage would most likely be above what is normally given to treat erectile dysfunction.

If clinical trials go well, cardiomyopathy due to Duchenne muscular dystrophy could become yet another off-label use for drug-maker Pfizer's popular ED drug. Though Viagra is already FDA approved, under the name Ravatio, to treat pulmonary hypertension, the drug has been used off-label by doctors for various problems related to circulation and heart function.

Some physicians have use the drug to treat infants with breathing problems with great success, Dr. Jerril Green, a critical care specialist at the Arkansas Children's Hospital in Little Rock, told ABCnews.com. In 2003, Green treated a boy named Chance Collins, then two years old, who was born three months prematurely and suffered from severe lung problems.

"The Viagra opens up the arteries in these children's lungs, allowing blood to flow in more easily," Green said.

WASHINGTON | Mon Oct 18, 2010 10:41pm EDT
Viagra may help heart effects of muscular dystrophy

A box of Viagra, typically used to treat erectile dysfunction, is seen in a pharmacy in Toronto January 31, 2008. REUTERS/Mark Blinch

(Reuters) - Viagra, developed to help ailing hearts long before it got a more high-profile job fighting erectile dysfunction, might help treat heart symptoms of  muscular dystrophy, researchers reported on Monday.

Tests in mice genetically engineered to have a condition similar to Duchenne muscular dystrophy showed the drug could improve how the heart works, Joseph Beavoa of the University of Washington and colleagues at the University of North Carolina found.

It is not clear just how the drug is helping the mice, they reported in the Proceedings of the National Academy of Sciences, but they said it may be worth trying it as a treatment for muscular dystrophy.
Duchenne muscular dystrophy affects an estimated one in 3,500 males, according to the National Institutes of Health.

"Duchenne muscular dystrophy (DMD) is a progressive and fatal genetic disorder of muscle degeneration. Patients with DMD lack expression of the protein dystrophin as a result of mutations in the X-linked dystrophin gene," the researchers wrote.

Because of the involvement of the X chromosome, boys are far more likely to be affected than girls, who have two copies of the X chromosome and, thus, are likely to have a "spare" copy of the healthy gene.

Muscles all over the body break down as the patient grows up, the heart included. Many patients die of heart failure and most patients with the condition die before age 40.

Viagra, known generically as sildenafil, is sold by Pfizer Inc for erectile dysfunction and under the brand name Revatio to treat a heart condition called pulmonary hypertension. It is in a class of drugs called PDE5 inhibitors that work in a variety of ways to increase blood flow.

The team, working with funds from the NIH and non-profit groups, tested Viagra in mice that had heart damage similar to that seen in muscular dystrophy.

It slowed the damage and in some cases reversed it, they found.

"Although PDE5 inhibitors will certainly not cure DMD, the current studies suggest that they could be used in combination with current or future therapies," the researchers wrote.

(Reporting by Maggie Fox; Editing by Paul Simao)
Source: http://www.reuters.com/article/idUSTRE69H4MW20101019