Recommendations for cardiac monitoring of adults with canalopathy on mexiletine

Cardiac monitoring is recommended in adults with muscular canalopathy treated for myotonia with mexiletine (Namuscla®), due to a possible pro-arrhythmic effect of the product.

• To help prescribers, a number of experts – cardiologists and neurologists from various French reference centres, and an Italian pharmacologist – have issued recommendations concerning cardiac monitoring of adults being treated, based on the summary of product characteristics (SPC), a review of the literature and their clinical experience.
• They emphasise the benefit/risk ratio in favour of mexiletine for myotonia.
• An electrocardiogram (ECG) is recommended every two years during treatment (or more frequently if deemed necessary).
• For patients with cardiac abnormalities who have no contraindications to mexiletine, an electrocardiogram and echocardiography should be performed every year.
• They have also developed a decision algorithm to guide the initiation and monitoring of treatment.

Recommendations of an expert group for the cardiac assessment of non-dystrophic myotonia adult patients treated with mexiletine. Vicart S, Wahbi K, Duchateau J et al. Neuromuscul Disord. 2024 Nov.