Study of Ranolazine in Myotonia Congenita, Paramyotonia Congenita and Myotonic Dystrophy Type 1

Study Overview
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Brief Summary
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The purpose of this study is to gather preliminary data to determine if ranolazine is a safe and effective treatment for the symptoms of myotonia congenital, paramyotonia congenita, and myotonic dystrophy type 1. The duration of the study is 5 weeks.

Detailed Description
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Recent advances in the understanding of myotonia congenita have identified potential areas that could possibly respond to treatment in a drug study. The drug ranolazine (trade name Ranexa) is a FDA-approved medication to treat chest pain in patients with heart disease. Ranolazine has been studied in mice with myotonia congenita. The data from this animal model suggest that ranolazine may improve the symptoms and signs of myotonia. All individuals that participate will be placed on active drug. The investigators want to see if this drug is safe to take without causing too many side effects for people with myotonia congenita, paramyotonia congenital and myotonic dystrophy type 1. Participants will go to The Ohio State University for study visits. Participants will take ranolazine for four weeks. Participants can expect a total of 4 study visits and 2 phone calls over the 5 week period.

Official Title
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Open Label Trial of Ranolazine in Myotonia Congenita, Paramyotonia Congenita, & Myotonic Dystrophy Type 1

Conditions
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Myotonia Congenita, Paramyotonia Congenita, Myotonic Dystrophy 1

Intervention / Treatment
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* Drug: Ranolazine


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Diagnosis of myotonia congenital, paramyotonia congenital or Myotonic Dystrophy Type 1 established by genetic testing in the subject or in a first-degree relative. Clinically evident myotonia Exclusion Criteria: Contraindications to ranolazine use: for fungus infection: ketoconazole (Nizoral), itraconazole (Sporanox, Onmel) for infection: clarithromycin (Biaxin) for depression: nefazodone for HIV: nelfinavir (Viracept), ritonavir (Norvir), lopinavir and ritonavir (Kaletra), indinavir (Crixivan), saquinavir (Invirase). for tuberculosis (TB): rifampin (Rifadin), rifabutin (Mycobutin), rifapentine (Priftin) for seizures: phenobarbital, phenytoin (Phenytek, Dilantin, Dilantin-125), carbamazepine (Tegretol) the herbal supplement St. John's wort you have scarring (cirrhosis) of your liver Concurrent use of mexiletine, lacosamide, acetazolamide, phenytoin, quinine, procainamide, Saint John wort or tocainide. Patients who were previously treated with these medications may participate. They need to be off of the medication for at least a week prior to enrollment. QTc >470 ms for men and >480 ms for women. Women who are pregnant or breastfeeding Direct family history of sudden cardiac death

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 100 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: ranolazine<br>ranolazine 500mg, twice daily for two weeks; 1000mg twice daily for 2 weeks | Drug: Ranolazine<br>* Ranexa is FDA approved for chronic angina<br>* Other names: Ranexa®;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Questionnaires: Short Form Health Survey (SF-36) and Individualized Neuromuscular Quality of Life Questionnaire (INQoL) | quality of life measurements for overall health and neuromuscular disease | 1 month | 
| Muscle tasks | The subject is observed and timed while rising from an arm chair, walking 3 meters, turning, walking back, and sitting down again | 1 month | 
| Electromyography (EMG) Myotonia | To see if the electrical potentials produced by the muscle fibers change. | 1 month | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Electrocardiogram (ECG) | to measure heart function and observe QT interval (a measure of the time between the start of the Q wave and the end of the T wave in the heart's electrical cycle) | 1 month | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Myotonia Congenita, ranolazine, Ohio State, Open Label, Paramyotonia Congenita, Myotonic Dystrophy 1