Viagra and Cialis, normally used for treating male impotence, could be used to fight a muscle-wasting disorder which affects boys, say US scientists.
In tests the drugs helped improve blood flow to the muscles of boys with Duchenne muscular dystrophy (DMD).
They hope it could slow the onset of the disease, which causes the breakdown and gradual loss of muscle fibres.
Experts said the study could be beneficial but would not necessarily improve the boys' ability to walk.
DMD affects one in every 3,500 newborn boys, and many will die before they reach 30. It can become fatal when it affects the muscles needed to breathe and pump blood around the body.
Many patients with the condition have to use a wheelchair by the age of 10, and there is currently no effective treatment.
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