Effectiveness of Mexiletine for Treating People With Non-Dystrophic Myotonia

• Register: ClinicalTrials.gov
• Last refreshed on: 19 October 2017
• Main ID: NCT00832000
• Date of registration: 27/01/2009
• Prospective Registration: No
• Primary sponsor: Richard Barohn, MD
• Public title: Effectiveness of Mexiletine for Treating People With Non-Dystrophic Myotonia
• Scientific title: Phase II Therapeutic Trial of Mexiletine in Non-Dystrophic Myotonia
• Date of first enrolment: December 2008
• Target sample size: 59
• Recruitment status: Completed
• URL: https://clinicaltrials.gov/show/NCT00832000
• Study type: Interventional
• Phase: Phase 2

Countries of recruitment

Canada, Italy, United Kingdom, United States

Key inclusion & exclusion criteria

Inclusion Criteria:

- Clinical symptoms or signs suggestive of myotonic disorders

- Presence of myotonic potentials on electromyography (EMG)

- Participant in the Non-Dystrophic Natural History study (RDCRN 5303) or a new patient
with confirmed non-dystrophic myotonia

Exclusion Criteria:

- Other neurological condition that might affect the assessment of the study
measurements

- Genetic confirmation of DM1 (more than 50 repeats of CTG) or DM2

- Existing cardiac conduction defects, as evidenced on EKG, including but not limited to
the following conditions: malignant arrhythmia or cardiac conduction disturbances
(e.g., second degree AV block, third degree AV block, or prolonged QT interval)

- Existing permanent pacemaker

- Current use of any of the following antiarrhythmic medications for a cardiac disorder:
flecainide acetate, encainide, disopyramide, procainamide, quinidine, propafenone, or
mexiletine

- Use of medications for myotonia, such as phenytoin and flecainide acetate, within 5
days of study entry; carbamazepine and mexiletine within 3 days of study entry; or
propafenone, procainamide, disopyramide, quinidine, and encainide within 2 days of
study entry

- Use of medications that produce myotonia, which may include fibrate acid derivatives,
hydroxymethylglutaryl CoA reductase inhibitors, chloroquine, and colchicines

- Kidney or liver disease

- Heart failure

- Seizure disorder

- Pregnant or breastfeeding



Age minimum: 16 Years
Age maximum: N/A
Gender: All

Health Condition(s) or Problem(s) studied

Non-Dystrophic Myotonia

Myotonia

Intervention(s)

Drug: Mexiletine

Drug: Placebo

Primary Outcome(s)

Patient-reported Stiffness on the IVR [Time Frame: Weeks 3-4 of each period]

Secondary Outcome(s)

Compound Motor Action Potentials After Long Exercise Test [Time Frame: The end of period 1 (week 4) and period 2 (week 9)]

Compound Motor Action Potentials After Short Exercise Test [Time Frame: The end of period 1 (week 4) and period 2 (week 9)]

Graded Myotonia by Needle Electromyography - Right Tibialis Anterior [Time Frame: The end of period 1 (week 4) and period 2 (week 9)]

Clinical Hand Grip Myotonia Evaluation (Seconds) [Time Frame: The end of period 1 (week 4) and the end of period 2 (week 9)]

Graded Myotonia by Needle Electromyography - Right Abductor Digiti Minimi [Time Frame: The end of period 1 (week 4) and period 2 (week 9)]

Clinical Eye Closure Myotonia Evaluation (Seconds) [Time Frame: The end of period 1 (week 4) and the end of period 2 (week 9)]

Short Form 36 - Mental Composite Score [Time Frame: The end of period 1 (week 4) and period 2 (week 9)]

Quantitative Measure of Hand Grip Myotonia (Seconds) [Time Frame: The end of period 1 (week 4) and period 2 (week 9)]

Short Form 36 - Physical Composite Score [Time Frame: Particiapnts who experienced weakness on mexiletine in either period 1 or period 2.]

Patient Reported Tiredness on the IVR [Time Frame: Weeks 3-4 of each period]

Individualized Neuromuscular Quality of Life Scale - Summary Score [Time Frame: The end of period 1 (week 4) and period 2 (week 9)]

Patient Reported Weakness on the IVR [Time Frame: Weeks 3-4 of each period]

Patient Reported Pain on the IVR [Time Frame: Weeeks 3-4 of each period]

Secondary ID(s)

11050

FDA OPD RO1FD003454

Source(s) of Monetary Support

Please refer to primary and secondary sponsors

Results

• Results available: Yes
• Date Posted: 11/03/2013
• URL: https://clinicaltrials.gov/ct2/show/results/NCT00832000