Amlodipine Plus Botulinum Toxin for Focal Dystonia

Objective: To determine if the calcium channel blocker, amlodipine can augment the effect of botulinum toxin injections in the treatment of focal dystonia.

Study Population: 20 patients with cervical dystonia

Design: Double-bind, placebo-controlled clinical trail.

Outcome measures: dystonia rating scales (TWISTRS)

• INCLUSION CRITERIA:

Patients enrolled in Protocol 85-N-0195, Efficacy and Pathophysiology of Botulinum Toxin for Treatment of Involuntary Movement Disorders are eligible for enrollment if they meet the following inclusion and exclusion criteria.

Good general health

Focal hand dystonia or cervical dystonia

Stable response to botulinum toxin demonstrated through a series of at least 3 injections over a period of at least a year

Benefit from the 3 immediately prior btx injections rated as 75% or less or a duration of benefit lasting less than or equal to 2 months

No other medications for dystonia

Exclusion criteria

Cervical dystonia accompanied by dysphagia or dyspnea, either before or with botulinum toxin injection

Present or past cardiac disease, hypertension, arrhythmia or congestive heart failure

Anterocollis or other neck dystonia requiring bilateral anterior neck muscle injections

Use of concomitant medications affecting calcium channels or those metabolized by the cytochrome p450 3A4 system including grapefruit juice, St. John's wort, HIV protease inhibitors, cimetidine, antibiotics (macrolides, fluoroquinones, antifungal, rifampin), antidepressants (fluvoxamine, norfluoxetine), barbiturates, anticonvulsants (carbamazepine, phenytoin), oral diabetes agents (pioglitazone, troglitazone), and glucocorticoids

Allergy to amlodipine or related compounds

Pregnany/ nursing

Age less than 18 years of age

Abnormal EKG

Abnormal coagulation profile or liver function tests

Use of anticoagulants