Conventional Psychotropic-Induced Tremor Extinguished by Olanzapine
TO THE EDITOR: We have observed, unexpectedly, the disappearance of prominent, persistent, and troublesome fluphenazine- or haloperidol-induced coarse tremors in three patients within days of initiation of treatment with olanzapine, 10 mg/day p.o., without discontinuance of or decrement in the dose of either fluphenazine or haloperidol. Treatment with diphenhydramine, benztropine, amantadine, and propanolol—tried in cases 1 and 2 only—had provided negligible and transient tremor relief. Our intent, then, was to wean all three patients from fluphenazine or haloperidol while starting olanzapine, but we observed the following responses:
Case 1. Mr. A, a 36-year-old Caucasian man with an 18-year history of recurrent command hallucinations, suicide attempts, paranoid delusions, severe depression, and alcohol dependence, had been in remission for 1 year on a regimen of fluphenazine decanoate, 37.5 mg i.m. every 2 weeks, and nefazodone, 100 mg p.o. at bedtime. The patient experienced coarse truncal and extremity tremors. Four days after the addition of olanzapine, 10 mg/day p.o., to his regimen, his tremors had noticeably diminished; by day 7, they were no longer apparent. Without further medication adjustment, the tremors had not returned after 26 weeks.
Case 2. Ms. B, a 25-year-old African American woman with a 2-year history of recurrent paranoid ideation, violent behavior, psychotic depression, and mania, with intercurrent marijuana, heroin, and “crack” cocaine abuse, had been in remission for 1 year on a regimen of fluphenazine decanote, 25 mg i.m. every 2 weeks; fluphenazine, 7.5 mg p.o. at bedtime; and divalproex sodium, 1000 mg p.o. twice a day. She had developed coarse hand tremors that disappeared within 7 days of the addition of olanzapine, 10 mg p.o.; her tremors had not returned after 21 weeks without other medication changes.
Case 3. Ms. C, a 34-year-old African American woman with a 20-year history of recurring severe thought disorganization or mania, had been in remission for 1 year on a regimen of haloperidol, 20 mg p.o. at bedtime; lithium carbonate, 300 mg p.o. twice a day; and divalproex sodium, 750 mg p.o. twice a day. She had unsightly coarse circumoral and hand tremors, not relieved with lithium discontinuance. Her tremors disappeared 1 week after initiation of treatment with olanzapine, 10 mg/day p.o., without other medication adjustments; her tremors had not returned after 20 weeks.
Olanzapine is active against muscarinic cholinergic receptors (1), a fact that may account for the observed suppression of fluphenazine- and haloperidol-induced tremor. The patients in cases 1 and 2, however, had been treated with benztropine, an antagonist of muscarinic acetylcholine receptors, with little tremor relief, suggesting that olanzapine could suppress tremor by means other than antimuscarinic action.
1 Bymaster FP, Rasmussen K, Calligaro DO, Nelson DL, DeLapp NW, Wong, DT, Moore, NA: In vitro and in vivo biochemistry of olanzapine: a novel, atypical antipsychotic drug. J Clin Psychiatry 1997; 58(suppl 10): 28–36Google Scholar
