Pharmacological therapy of non-dystrophic myotonias

Objectives. Non-dystrophic myotonias (NDM) are rare diseases due to mutations in the voltage-gated sodium (Nav1.4) and chloride (ClC-1) channels expressed in skeletal muscle fibers. We provide an up-to-date review of pharmacological treatments available for NDM patients and experimental studies aimed at identifying alternative treatments and at better understanding the mechanisms of actions. Methods. Literature research was performed using PubMed and ClinicalTrial.gov. Results. Today, the sodium channel blocker mexiletine is the drug of choice for treatment of NDM. Alternative drugs include other sodium channel blockers and the carbonic anhydrase inhibitor acetazolamide. Preclinical studies suggest that activators of ClC-1 channels or voltage-gated potassium channels may have antimyotonic potential. Conclusions. An increasing number of antimyotonic drugs would help to design a precision therapy to address personalized treatment of myotonic individuals.