Radio receptor assay of serum neuroleptic levels in psychiatric patients.

The radioreceptor assay for the measurement of neuroleptic drugs in serum has been used to study the relationship between dose and serum level in schizophrenic patients receiving these drugs. The assay was found to be reproducible and capable of detecting neuroleptics in the sera of patients receiving a range of both oral and depot drugs, with the exception of trifluoperazine spansules. Linear correlations were obtained between daily dose and serum level for each drug both in individual patients on different doses and between patients on a stable dose. Extrapyramidal side effects were related to the serum neuroleptic level within, but not between, patients. The assay may be of use in clinical practice, including the assessment of compliance or poor response to neuroleptics.