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Monitoring plasma levels of fluphenazine during chronic therapy with fluphenazine decanoate

journal contribution
posted on 2023-05-16, 09:51 authored by Miller, RS, Gregory PetersonGregory Peterson, Stuart McLeanStuart McLean, Westhead, TT, Gillies, P
This study was conducted to examine the interpatient variability in steady–state plasma concentrations of fluphenazine by repeat depot intramuscular administration, and to determine the relationship between these concentrations and clinical state. Steady–state pre–dose concentrations of fluphenazine in plasma were measured using a sensitive and specific gas chromatography/mass spectrometry (GC/MS) assay in 24 patients with schizophrenia who were receiving continuous treatment with depot intramuscular fluphenazine decanoate. Clinical response was measured using the Andreasen Scale for positive and negative symptoms. Steady–state plasma concentrations of fluphenazine ranged from undetectable (< 0–l ng/ml) to 27-9 ng/ml, with a median of 0–5 ng/ml. No significant associations were found between plasma concentration and dosage, or age and sex of the patient. Steady–state plasma concentrations in patients taking anticholinergic agents were significantly higher than in patients not receiving such drugs (P < 0–05 by MannWhitney U–test). Poorer control, expressed as the sum of the negative symptom scores or the sum of the positive and negative symptom scores, was related to higher log transformed plasma concentrations of fluphenazine and higher fluphenazine decanoate dosage. The log transformed plasma concentrations of fluphenazine and the fluphenazine decanoate dosages were weakly related. Patients receiving another antipsychotic drug in addition to fluphenazine decanoate tended to have poorer clinical control and higher dosages of fluphenazine decanoate. These results indicate the useful role that plasma level monitoring can fulfil in identifying patients who are therapy–resistant despite high plasma levels.

History

Publication title

Journal of Clinical Pharmacy and Therapeutics

Volume

20

Pagination

55-62

ISSN

0269-4727

Department/School

School of Pharmacy and Pharmacology

Publisher

Wiley-Blackwell Publishing Ltd

Place of publication

United Kingdom

Rights statement

The definitive published version is available online at: http://onlinelibrary.wiley.com/

Repository Status

  • Restricted

Socio-economic Objectives

Other health not elsewhere classified

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