Namuscla (mexiletine) is a medication primarily used for the treatment of myotonia, a condition characterized by muscle stiffness that occurs in neuromuscular disorders such as myotonic dystrophy. It belongs to the class of drugs known as antiarrhythmics, which are typically used to treat irregular heartbeats, but in the case of Namuscla, its mechanism of action helps improve muscle function by reducing the muscle stiffness and relaxation difficulties associated with myotonia. Mexiletine, the active ingredient in Namuscla, works by blocking sodium channels in muscle cells, which helps normalize muscle excitability. This medication is taken orally and is available in capsule form. It is important for patients to follow their healthcare provider's instructions closely when taking Namuscla, as the dosage and treatment regimen can vary based on individual needs and response to the medication.