Non-Dystrophic Myotonia (NDM). Non-dystrophic myotonias are a group of rare neuromuscular disorders that cause episodes of muscle stiffness (known as myotonia) and paralysis. Predominantly the muscles of the face, hands and legs are affected. In addition to these episodes a permanent and debilitating muscle weakness can develop. The optimal treatment for these disorders is unknown. MedDRA version: 9.1 Level: HLGT Classification cod
Conditions
Interventions
Pharmaceutical Form: Capsule, hard
Pharmaceutical form of the placebo: Capsule, hard
Route of administration of the placebo: Oral use
Sponsors
University College London-Joint UCLH/UCL Biomedical (R&D) Unit
Eligibility
Sex/Gender
All
Inclusion criteria
Inclusion criteria: 1.Age 18 years or older 2.Clinical symptoms or signs suggestive of myotonic disorders 3.Presence of myotonic potentials on electromyography (EMG) 4. Participation in the Non-Dystrophic Myotonia Natural History study; or a new patient with genetically confirmed NDM; or a new patient with a first degree relative (parent, sibling or child) with genetically confirmed NDM; or a new patient with clinical features of NDM in whom the mutation has not been localized, who areis DM1 and DM2 negative. 5.Patients on a stable dose of the following medications for 30 days prior to enrollment. Medications are: a.fibrate acid derivatives b.hydroxymethylglutaryl CoA reductase inhibitors 6. Practising an acceptable method of birth control for the duration of the trial, if a women of child bearing potential. Are the trial subjects under 18? no Number of subjects for this age range: F.1.2 Adults (18-64 years) yes F.1.2.1 Number of subjects for this age range F.1.3 Elderly (>=65 years) yes F.1.3.1 Number of subjects for this age range
Exclusion criteria
Exclusion criteria: 1.Inability or unwillingness to provide informed consent 2.Other neurological conditions that might affect the assessment of the study measurements 3.Genetic confirme DM1 (CTG>100 repeats) or DM2, if patient does not have genetically confirmed NDM. 4.Patients with existing cardiac conduction defects, evidence on EKG including but not limited to the following conditions: malignant arrhythmia or cardiac conduction disturbances (such as second degree AV block, third degree AV block, or prolonged QT interval >500ms or QRS duration >150 msec). 5.Current use of the following medication for a cardiac disorder: flecainide acetate, encainide, disopyramide, procainamide, quinine, propafenone or mexiletine. 6.Women who are pregnant or lactating 7. Patients currently on medications for myotonia such as phenytoin and flecainide acetate within 5 days of enrollment, carbamazepine and mexiletine within 3 days of enrollment, or acetazolamide, propafenone, procainamide, disopyramide, quinidine and encainide within 2 days of enrollment. 8. Patients with an existing permanent pacemaker. 9. Patients with renal or hepatic disease, heart failure, or seizures disorders. 10. Patients on medications that produce myotonia. This includes one or more of the following: a. chloroquine b. colchicines
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Secondary Objective: In addition the study will also allow investigators to examine specific NDM (non-dystrophic myotonia) subtype responses to therapy.;Primary end point(s): Patient-assessed symptoms: mean stiffness as measured by an Interactive Voice Response Diary (IVR) of daily calls made during weeks 2 and 3, and 7 and 8 of the trial.;Main Objective: To assess whether mexiletine improves both quantitative and qualitative measures of myotnia (muscle stiffness) in patients with non-dystrophic myotonia. | — |
Countries
Italy, United Kingdom
Outcome results
None listed