Mexiletine is indicated for the symptomatic treatment of myotonia in adult patients with non-dystrophic myotonic disorders.
For this indication, competent medicine agencies globally authorize below treatments:
Oral
167 - 500 mg
From 167 To 500 mg once every day
167 mg
The recommended starting dose of mexiletine is 167 mg daily. After at least 1 week of treatment, based on the clinical response, the daily dose can be increased to 333 mg daily (2 capsules per day). After at least 1 further week of treatment, based on clinical response, dose can be further increased to 500 mg daily. Maintenance treatment is between 167 mg–500 mg daily, according to the intensity of symptoms and the clinical response, taken regularly throughout the day.
The dose should not exceed 500 mg/day. Regular reassessment should be implemented, not to continue long-term treatment in a patient not responding or not experiencing benefit of the treatment. Before starting mexiletine treatment, detailed and careful cardiac evaluation should be carried out; throughout treatment with mexiletine, cardiac monitoring needs to be continued and adapted as a function of the heart condition of the patient.
In case of modification of the mexiletine dose, or if medicinal products susceptible to affect cardiac conduction are co-administered with mexiletine, patients should be closely monitored by ECG (especially patients with conduction anomalies).