Washington: A new study has found that a drug most often used to treat heart arrhythmias also reduces a central symptom of myotonic dystrophy, the most common type of muscular dystrophy in adults.
The findings about the medication mexiletine – a chemical cousin of lidocaine – were published May 4 in the journal Neurology, a publication of the American Academy of Neurology.
Currently there is no drug approved to treat myotonic dystrophy, an inherited disease that is marked by progressive muscle weakness. While the course of the disease can vary dramatically from patient to patient, symptoms besides weakness can include muscle stiffness, difficulty speaking and swallowing, problems walking, and in some patients, heart problems and cataracts.
The researchers at the University of Rochester Medical Center found that mexiletine is effective at treating the myotonia – muscle stiffness – that is at the center of the disease. Turning a key in a lock, writing with a pen or pencil, picking up and setting down a pitcher of water – all are formidable tasks for patients with myotonia. Sometimes the symptom first occurs when a patient shakes someone’s hand, then cannot relax his or her grip for several seconds.
While several doctors have suspected that mexiletene helps relieve myotonia, this is the first placebo-controlled, double-blind study to show that it actually does so, said neurologist Richard Moxley III, M.D., an author of the study and an international expert on muscular dystrophy.
“It’s important for physicians who treat patients to know that mexiletine is an option,” said Moxley, who is director of the University’s Neuromuscular Disease Center and professor of Neurology. “Several physicians who specialize in treating patients with myotonic dystrophy have found it to be effective for their patients, but we really wanted to study the issue closely. The medication really addresses myotonia quite well, with no additional risk.” (ANI)