The findings come from one of the world's premier groups focusing on research and new treatments for muscular dystrophy. Ten years ago Moxley began the world's first muscular dystrophy registry, which now includes more than 1,500 patients with either myotonic dystrophy or facioscapulohumeral dystrophy.
Moxley also heads the University's Senator Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, one of three research centers originally created in 2003 by the National Institutes of Health. The Rochester center is now one of six NIH Wellstone centers and most recently received $5 million in additional funding in September 2008 to continue its work for five more years.
In the trial of mexiletine, evaluators measured the amount of time it took patients to relax their grip after squeezing the handles of a computerized device that measures force. For most healthy people, that relaxation takes one-third of a second or less. But for people with myotonic dystrophy, that relaxation can take many seconds.
Scientists studied two groups of 20 patients who had myotonic dystrophy, all confirmed through genetic analysis. Each participant received either placebo, or 150 or 200 milligrams of mexiletine three times a day, for seven weeks. Then, after a period of several weeks where they received no drug, participants were switched to the other treatment for another seven weeks.
The team found that mexiletine at three daily doses of either 150 or 200 milligrams per dose does a great deal to alleviate myotonia. In their test of relaxation after grip, the team found that mexiletine reduces the abnormally long relaxation by 38 percent at the lower dose and 59 percent at the higher dose. No benefit at all was seen for participants on placebo.
Because the drug can affect the heart, participants in the study were admitted as inpatients and stayed several nights at the Univers
|Contact: Tom Rickey|
University of Rochester Medical Center