The Effectiveness of Shakuyaku-kanzo-to on Myotonia in a Case of Myotonic Dystrophy / 日本東洋医学雑誌

The effectiveness of Shakuyaku-kanzo-to on myotonia in a 50-year-old female with myotonic dystrophy is reported. Neurological examination showed myogenic distal dominant muscle weakness and myotonia. Treatment with Shakuyaku-kanzo-to improved myotonic time from 12.8 to 6.8 seconds. This effect was equal to phenytoin and mexiletine. The results indicated that Shakuyaku-kanzo-to affected the ion channels of the skeletal muscle membrane. The apaminsensitive K channel was speculated to be the affected site of the ion channel. Glycyrrhizin might play an important role in this mechanism.<br>Five week treatment with Shakuyaku-kanzo-to showed no adverse effects on the myopathy.