Neuroleptic Plasma Levels Research Articles

Within-individual variation in steady state plasma levels of different neuroleptics and prolactin.

Eleven male chronic schizophrenics were given, serially, oral pimozide, fluphenazine, and flupenthixol; the two latter were also given intramuscularly as decanoates in oil. Oral haloperidol was given before and after each drug. Analysis of variance of steady state plasma levels of the different neuroleptics showed considerable within-individual variation in such levels, probably due to differences in absorption and metabolism and between routes of administration. The findings suggest that if a patient fails to respond to one neuroleptic, there may be good pharmacokinetic reasons for switching him to another belonging to a different group, or for giving the same neuroleptic by a different route of administration. The study also showed that previous administration of one neurololeptic may influence the steady state level of another. The various neuroleptics produced different effects on plasma prolactin levels.

Effect of a drug holiday on plasma chlorpromazine levels in chronic schizophrenic patients.

Low chloropromazine (CPZ) levels have been measured in chronically treated schizophrenics. We tested six such patients to determine whether a 2-week CPZ-free period (drug holiday) would improve plasma CPZ levels. We also monitored psychiatric symptoms, autonomic function, and extrapyramidal signs. We found these patients to have low predose CPZ levels that did not change appreciably after the drug holiday. Peak levels following the holiday averaged 28 +/- 7 ng/ml higher than those measured prior to the holiday. Drug holidays are safe and should be examined more thoroughly as a means of improving plasma neuroleptic levels in chronically treated schizophrenics.

Plasma levels of neuroleptics vs clinical response

The authors summarize the correlation of blood-plasma levels to clinical responses of all available psychotropic drugs and related medications. The optimal therapeutic plasma levels are tabulated. Ten different factors influencing the blood drug levels are discussed.