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March 1970

Factors Affecting Chlorpromazine Plasma Levels in Psychiatric Patients

Author Affiliations

Bethesda, Md; Washington, DC
From the Laboratory of Chemical Pharmacology, National Heart Institute (Dr. Curry), the Laboratory of Clinical Science, National Institute of Mental Health (Drs. Davis and Janowsky), National Institutes of Health, Bethesda, Md, and St. Elizabeth's Hospital, Washington, DC (Dr. Marshall). Dr. Curry is currently with the Department of Pharmacology and Therapeutics, The London Hospital Medical College, London.

Arch Gen Psychiatry. 1970;22(3):209-215. doi:10.1001/archpsyc.1970.01740270017002

IT RECENTLY became possible to Measure concentrations of chlorpromazine and some of its relatively nonpolar metabolites in the plasma of psychiatric patients.1 As a result chlorpromazine, the demethylated analogues of chlorpromazine, and chlorpromazine sulfoxide, were identified unequivocably for the first time in human plasma.2-4 These preliminary studies showed considerable interpatient and intrapatient variation in plasma levels of these materials in subjects on similar chlorpromazine dosage regimens. The clinical significance of this finding is that certain patients may have a poor response to medication because of variations in rates of absorption and metabolism, resulting in unusually high or low plasma and tissue levels. The present report describes an investigation of some of the factors which modify plasma levels of chlorpromazine.

Methods  Plasma samples were collected in a disposable aspirating syringe (Vacutainer tubes, B-D Products), containing potassium oxalate, from acutel" and

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