The erectile dysfunction drug tadalafil (Cialis, Eli Lilly) can correct abnormal blood flow in patients with Becker muscular dystrophy and could in the future be used to slow progression of the disorder, researchers said.
The findings suggest that tadalafil could be used as a treatment to slow or prevent muscle weakening and help patients retain more function for longer.
Becker muscular dystrophy is an inherited disorder that involves slowly worsening muscle weakness of the legs and pelvis. It occurs in about 3 to 6 out of every 100 000 births.
Patients with Becker muscular dystrophy often have difficulties with walking that get worse over time. There is no cure for the condition, and by the age of 25 to 30 many patients are unable to walk.
How the study was done
In a small study involving men with the disorder, researchers from the Cedars-Sinai Medical Centre in Los Angeles took measurements when volunteers' forearm muscles were either rested or lightly exercised with a handgrip.
They found that almost all the patients had defective blood flow when they exercised. This lack of blood flow may contribute to muscle fatigue and weakness, the researchers wrote in a paper in the journal Science Translational Medicine this week.
But after giving some of the patients a single oral dose of tadalafil and comparing them to others given a placebo, the scientists found that normal blood flow was restored to the muscles of 8 out of 9 patients who got the drug.
Like other erectile dysfunction drugs, tadalafil dilates blood vessels and is designed to increase blood flow. In the impotence drug market, it is a longer-acting alternative to sildenafil (Viagra, Pfizer).
The researchers cautioned that more, larger studies are needed to show whether the improved blood flow has a meaningful effect on dystrophic muscles.
(Reuters Health, November 2012)