Mexiletine and Non Dystrophic Myotonias

"* Blisters of 10 capsules of 200 mg mexiletine hydrochloride.~* Patients will receive gradual dose of the treatment as it would be done in clinical practice.~* Mexiletine will be started at 200 mg / day (1 capsule to be taken at the beginning of the meal) and will be increased by 200mg every 3 days to reach a maximum of 600mg / day in 3 taken in 1 week.~* The duration of each treatment period is 18 days minimum (maximum 22 days)."