Tardive dyskinesia and depot fluphenazine

Variation in oro-facial tardive dyskinesia during depot antipsychotic drug treatment

Oro-facial (tardive) dyskinesia, occurring in patients on long-term antipsychotic (dopamine antagonist) medication, can be suppressed temporarily by increasing the drug dose. Lowering the dose can exacerbate the condition. In patients receiving regular fluphenazine decanoate (FPZ) and flupenthixol decanoate (FPT) injections, characteristic profiles of the fluctuations in plasma level concentrations, occurring during the injection interval, have been demonstrated. The possible effects of these relatively predictable plasma level changes on the severity of oro-facial dyskinesia, and parkinsonism, were investigated. Regular assessment of oro-facial dyskinesia throughout the injection interval was carried out in six patients receiving FPZ and two patients receiving FPT. In both groups, changes were observed in the severity of oro-facial dyskinesia consistent with the expected effects of drug level fluctuations. The main implication of this finding is that, in investigations of tardive dyskinesia in patients receiving depot medication, ratings should be carried out at a standard time relative to injections.

Serum concentrations of cis(Z)-flupentixol and prolactin in chronic schizophrenic patients treated with flupentixol and cis(Z)-flupentixol decanoate

Nine chronic schizophrenic patients selected from three hospital departments were treated with flupentixol (orally and IV) and cis(Z)-flupentixol decanoate in Viscoleo (IM) in a three-phase pharmacokinetic study. Oral administration (single and repeated dosage) showed a relatively slow absorption with maximum serum concentration around 4 h after administration. Intravenous injection indicated multicompartment kinetics for cis(Z)-flupentixol. The biological half-lives calculated after the different doses were the same, indicating that the pharmacokinetics of cis(Z)-flupentixol does not differ between single and repeated administration and does not change when moderately higher doses are given. The bioavailability of orally administered cis(Z)-flupentixol was calculated to be about 40% with IV injection as reference. After IM administration maximum serum concentration was seen between 4 and 10 days in most patients. Calculation of a disappearance half-life gave very variable results, indicating that the release of the drug from the oil depot is not a monoexponential process. The intramuscular depot had a much lower bioavailability than IV injection, which means that steady state has not been obtained after 8 weeks of depot treatment. Serum prolactin concentrations were elevated during neuroleptic treatment, but no correlation was found between prolactin concentrations and the serum concentrations of cis(Z)-flupentixol. A correlation between the changes in clinical ratings and concentrations of cis(Z)-flupentixol or prolactin was not found.