A drug typically prescribed for erectile dysfunction or increased pressure in the arteries may be able to help treat the effects of muscle disease in boys, according to a recent study.

The drug tadalafil could help treat Duchenne muscular dystrophy, a progressive and fatal muscle disease affecting boys and young men that causes loss of muscle function. There is no specific treatment for the disease, which is genetic.

Corticosteroids can slow muscle degeneration and help temper the effect on lung and heart function, but they have many side effects and more than a quarter of people with the disease cannot tolerate the drugs.

For the study, researchers recruited 10 boys between the ages of 8 and 13 years old with Duchenne muscular dystrophy who were taking corticosteroids first were compared to 10 healthy boys of the same age. Then researchers measured the blood flow in all of the participants' muscles when they were at rest and when they were doing a handgrip exercise.

Based on the results, boys with Duchenne did have blood flow abnormalities, even though they were taking corticosteroids.

Next the boys with Duchenne received either tadalafil or the drug sildenafil and the tests were repeated. After waiting two weeks, the boys received the other drug and were tested again.

Researchers said that after taking either drug, the boys' blood flow response during exercise was the same as that of the boys who did not have the disease.

"The effect was immediate and dramatic. The result also was more pronounced with higher doses," Ronald G. Victor study author and assistant director of the Cedars-Sinai Heart Institute, said in a statement.

Victor said more research is needed before recommending the drugs for people with Duchenne muscular dystrophy.

"This is not a cure, but it is the first stop toward identifying potential treatments," he said.

The findings were recently published in the online issue of Neurology.