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Risperidone and Olanzapine May Reduce Risk of Extrapyramidal Symptoms
A DGReview of :"Risk of extrapyramidal syndromes with haloperidol, risperidone, or olanzapine"
Annals of Pharmacotherapy
01/17/2002
By Mark Greener
Risperidone and olanzapine have been shown to reduce the risk of extrapyramidal symptoms compared to haloperidol in an out-patient clinical setting.
Many studies of antipsychotics enroll chronically ill hospitalised patients. However, increasingly patients with schizophrenia are treated in the community and receive doses of drugs that were not assessed in these clinical trials.
A Dutch study aimed to quantify the risk of extrapyramidal symptoms associated with haloperidol, risperidone and olanzapine in an out-patient clinical practice setting.
Researchers from Utrecht University and other Dutch centres analysed a database containing filled prescriptions from 450,000 people to define first-time users of haloperidol, risperidone or olanzapine. This yielded 424, 243 and 181 patients who filled a first-time prescription for each drug group, respectively. The prescribed dose tended to be lower than that recommended in many management guidelines.
During the first 90 days of treatment, the authors assumed that a new prescription for antiparkinsonian agents would reflect the development of extrapyramidal symptoms.
A greater proportion of patients who received risperidone or olanzapine required antiparkinsonian therapy than did those who received haloperidol (36.2, 40.3 and 4.5 percent, respectively).
The database revealed that 13.2 percent of patients taking haloperidol started taking antiparkinsonian medication within 90 days. This compared to 11.9 and 5.0 percent of the risperidone and olanzapine groups, respectively -- an adjusted relative risk of 0.57 and 0.19, respectively.
Risperidone and olanzapine also were associated with a reduced risk of extrapyramidal symptoms irrespective of previous use of antiparkinsonian medication. However, not all these differences reached statistical significance.
On the other hand, was no significant difference in the likelihood of developing extrapyramidal symptoms among those taking risperidone and who had a history of such symptoms compared to those taking haloperidol: the relative risk was 1.30. The authors suggest that this finding requires further study.
They conclude that risperidone and olanzapine seem to be associated with a reduced risk of extrapyramidal symptoms compared to haloperidol in patients with similar treatment histories.
Annals of Pharmacotherapy 2001;35:1517?1522
"Risk of extrapyramidal syndromes with haloperidol, risperidone, or olanzapine"
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