Development of the Clinical Myotonia Rating Scale and a Mexiletine Prescribing and Monitoring Algorithm for Patients with Non-Dystrophic Myotonia

The two most common forms of non-dystrophic myotonia (NDM) are congenita (Thomsen disease or Becker-type) and paramyotonia congenita. Symptoms, including muscle stiffness, cramps, transient weakness, can affect a person’s quality life. An unmet need for validated tool to assess symptom severity frequency, as well disability caused by myotonia, led the development Clinical Myotonia Rating Scale (CMRS). At 9th Congress European Academy Neurology (EAN), Budapest, Hungary, 1st–4th July 2023, poster was presented regarding validation reliability testing CMRS, results which discussed here. Such is needed when first assessing symptoms in patient with NDM, their response myotonia-targeting medication. One such drug mexiletine, Class 1B antiarrhythmic agent that approved treatment adults NDM. Although number studies, clinical real-world trials people have not found mexiletine be associated impaired cardiac function, but an drug, assessment required prescription. Also at 2023 EAN meeting algorithm aid prescribers understanding patients whom may contraindicated, tests prior prescribing, monitoring under This developed utilising expert opinion, summary product characteristics, literature review safety data