Amlodipine Plus Botulinum Toxin for Focal Dystonia

* 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