Fluphenazine plasma level monitoring for patients receiving fluphenazine decanoate

Abstract

Background: Finding a dose of an antipsychotic for maintenance therapy that is both safe and effective can be difficult because clinicians are unable to titrate dose against clinical response in patients who are already stable. Therapeutic monitoring of antipsychotic plasma levels has the potential for helping clinicians in dosage selection. With this in mind, we evaluated the usefulness of monitoring fluphenazine plasma levels for patients with schizophrenia who were receiving maintenance treatment with fluphenazine decanoate.

Method: Thirty-one patients with schizophrenia were randomly assigned to low, medium, or high (0.1-0.3, 0.3-0.6, 0.6-1.0 ng/ml) plasma levels of fluphenazine. The dose of fluphenazine decanoate was adjusted in order to maintain patients in their assigned range. Side effects, psychopathology, and psychotic exacerbations were measured during the year following randomization.

Results: All of the psychotic exacerbations occurred during the first eight weeks following randomization, before patients had adequate time to reach their plasma level assignments. We did not find a relationship between plasma levels of fluphenazine and clinical outcomes or side effects.

Conclusion: Our results do not provide support for the usefulness of monitoring fluphenazine plasma levels for patients receiving fluphenazine decanoate.