On this page

What is myotonia?

Myotonia is a neuromuscular condition in which the relaxation of a muscle is impaired. It can affect any muscle group. Repeated effort generally is needed to relax the muscle, although the condition usually improves after the muscles have warmed-up.

Individuals with myotonia may:

  • Have trouble releasing their grip on objects
  • Have difficulty rising from a seated position
  • Walk with a stiff gait

Myotonia is caused by an abnormality in the muscle membrane and is often associated with inherited neurological disorders. It is commonly seen in individuals with myotonic muscular dystrophy, myotonia congenita, and in people who have one of a group of neurological disorders called channelopathies, which are inherited diseases caused by mutations in the chloride sodium or potassium channels that regulate the muscle membrane. Myotonia may also be triggered by exposure to cold.

Treatment may include mexiletine, quinine, phenytoin, and other anticonvulsant drugs. Physical therapy and other rehabilitative measures may help muscle function. Myotonia is a chronic disorder; however, symptoms may improve later in life.

Learn About Clinical Trials
Clinical trials are studies that allow us to learn more about disorders and improve care. They can help connect patients with new and upcoming treatment options.

How can I or my loved one help improve care for people with myotonia?

Consider participating in a clinical trial so clinicians and scientists can learn more about myotonia and related disorders. Clinical research uses human volunteers to help researchers learn more about a disorder and perhaps find better ways to safely detect, treat, or prevent disease.

All types of volunteers are needed—those who are healthy or may have an illness or disease—of all different ages, sexes, races, and ethnicities to ensure that study results apply to as many people as possible, and that treatments will be safe and effective for everyone who will use them.

For information about participating in clinical research visit NIH Clinical Research Trials and You. Learn about clinical trials currently looking for people with myotonia at

Where can I find more information about myotonia?

Information may be available from the following organizations and resources:


Muscular Dystrophy Association
Phone: 800-572-1717

National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
 301-495-4484 or 877-226-4267

Learn about related topics

Order publications from the NINDS Catalog
The NINDS Publication Catalog offers printed materials on neurological disorders for patients, health professionals, and the general public. All materials are free of charge, and a downloadable PDF version is also available for most publications.