Tremor at rest is a classic symptom of
Parkinson's disease that causes significant disability and distress for the patient and is generally only weakly responsive to conventional treatment, like
anticholinergic and dopaminergic medication. This study describes the treatment with
Clozapine in patients with
Parkinson's disease, who despite optimal antiparkinson medical
therapy still have a major disabling
tremor at rest.
Clozapine is an "atypical"
neuroleptic agent, producing fewer extra pyramidal side effects common to conventional
antipsychotic drugs.
Clozapine, however, has as its most serious complication
agranulocytosis, and hence all patients taking
Clozapine must undergo blood tests at least several times a month. Under these frequent blood monitoring conditions, in this study
Clozapine produced a substantial alleviation of parkinsonian
tremor in 17 of 23 patients (73%). The beneficial response was reached with a relative low dose of
Clozapine (18 mg./day), while previous antiparkinson medication was kept unchanged. The improvement of
tremor at rest was noticeable generally within 2 weeks of beginning
Clozapine therapy. No tolerance to the antitremor efficacy of
Clozapine was seen during study-period of at least 6 months. Leucopenia developed in one patient, other major adverse events were
hypersalivation and day-time drowsiness. These findings confirm the substantial antitremor efficacy of
Clozapine in
Parkinson's disease.