Mexiletine for the Treatment of Focal Dystonia

Brief Title

Mexiletine for the Treatment of Focal Dystonia

Official Title

Mexiletine for the Treatment of Focal Dystonia

Brief Summary

Dystonia refers to a condition characterized by involuntary muscle contractions that may
cause pain, abnormal posture, or abnormal movements. The cause of dystonia is unknown, but
some researchers believe it is a result of overactivity in the areas of the brain responsible
for movement (basal ganglia).

Lidocaine is a drug used for the treatment of irregular heartbeats. It is given by injection.
Recent studies have shown that lidocaine is also effective for the treatment dystonia.
Mexiletine is a drug similar to lidocaine used for irregular heartbeats that can be taken by
mouth.

Researchers would like to test the effectiveness of Mexiletine for the treatment of dystonia.
Patients participating in the study will be divided into two groups;

Group 1 will take Mexiletine for six weeks then stop. They will remain drug free for one week
then begin taking a placebo "inactive sugar pill" for an additional six weeks.

Group 2 will take a placebo "inactive sugar pill" for six weeks then stop. They will remain
drug free for one week then begin taking a Mexiletine for an additional six weeks.

Throughout the study researchers will test the effectiveness of the treatment by evaluating
patients using clinical rating scales and neurophysiological studies. In addition,
researchers will test patient's reflexes in an attempt to find out where mexiletine works in
the nervous system.

Detailed Description

Dystonia is a complex neurological disorder with an unknown pathogenesis likely involving the
basal ganglia. There is no adequate treatment for dystonia. Recent studies using
intramuscular and intravenous lidocaine have shown improvement in dystonic movements. It has
been proposed that patients with dystonia have reduced presynaptic inhibition of alpha
motoneurons leading to overactivation in response to movement. This may also reflect a
hyperexcitability at the cortical level, which can be reduced by altering peripheral input.

Mexiletine, an antiarrhythmic similar to lidocaine, but available orally, may benefit
patients with dystonia, as has been shown in several recent open-label studies. This trial
offers the possibility of treating dystonia as well as further elucidating the level of
dysfunction in the nervous system in dystonic patients. We propose a double-blind cross over
study comparing mexiletine to placebo in the treatment of patients with idiopathic dystonia.
The patients will be evaluated by clinical rating scales as well as neurophysiological
studies. In order to study the physiologic effect and attempt to localize the neuroanatomic
sight of action of mexiletine, studies of peripheral reflexes, reciprocal inhibition and
cortical excitation will be performed. These studies will include blink reflex recovery
curves, tonic vibration reflex, H-reflex and transcranial magnetic stimulation.

Study Phase

Phase 2

Study Type

Interventional

Condition

Blepharospasm

Intervention

Mexiletine

Publications

* Includes publications given by the data provider as well as publications identified by National Clinical Trials Identifier (NCT ID) in Medline.

Recruitment Information

Recruitment Status

Drug

Estimated Enrollment

Start Date

July 1998

Completion Date

July 2002

Eligibility Criteria

        INCLUSION CRITERIA:

        Patients with focal dystonia, specifically writer's cramp and blepharospasm, will be
        eligible for study.

        Patients will need medical clearance, specifically, cardiac clearance, by their primary
        care physician. This will include an EKG within the past 12 months and no history of
        underlying cardiac disease.

        EXCLUSION CRITERIA:

        Patients with any of the following conditions will be excluded from the study: structural
        brain lesions, identifiable etiology for dystonia (such as stroke, trauma, Parkinson's
        Disease, Wilson's Disease, or peripheral neuropathy), contractures or fixed joint
        deformities, current or past use of neuroleptics, seizures, prior neurosurgery, or
        co-existent neurologic or general medical illness, including history of cardiovascular
        disease or peptic ulcer disease and pregnant or breast-feeding women.

        Patients who are taking or have taken mexiletine will be excluded as well.

Gender

All

Ages

N/A - N/A

Accepts Healthy Volunteers

No

Contacts

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Location Countries

United States

Location Countries

United States

Administrative Informations

NCT ID

NCT00001784

Organization ID

Secondary IDs

98-N-0130

Study Sponsor

National Institute of Neurological Disorders and Stroke (NINDS)

Study Sponsor

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Verification Date

July 2002