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


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.

Full Title of Study: “Open Label Trial of Ranolazine in Myotonia Congenita, Paramyotonia Congenita, & Myotonic Dystrophy Type 1″

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: N/A
    • Intervention Model: Single Group Assignment
    • Primary Purpose: Treatment
    • Masking: None (Open Label)
  • Study Primary Completion Date: December 18, 2017

Detailed Description

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.


  • Drug: Ranolazine
    • Ranexa is FDA approved for chronic angina

Arms, Groups and Cohorts

  • Experimental: ranolazine
    • ranolazine 500mg, twice daily for two weeks; 1000mg twice daily for 2 weeks

Clinical Trial Outcome Measures

Primary Measures

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

Secondary Measures

  • Electrocardiogram (ECG)
    • Time Frame: 1 month
    • 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)

Participating in This Clinical Trial

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

Gender Eligibility: All

Minimum Age: 18 Years

Maximum Age: 100 Years

Are Healthy Volunteers Accepted: No

Investigator Details

  • Lead Sponsor
    • Ohio State University
  • Collaborator
    • Gilead Sciences
  • Provider of Information About this Clinical Study
    • Principal Investigator: William Arnold, Associate Professor – Ohio State University
  • Overall Official(s)
    • William D Arnold, MD, Principal Investigator, Ohio State University


Novak KR, Norman J, Mitchell JR, Pinter MJ, Rich MM. Sodium channel slow inactivation as a therapeutic target for myotonia congenita. Ann Neurol. 2015 Feb;77(2):320-32. doi: 10.1002/ana.24331. Epub 2015 Jan 9.

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