Pharmacokinetic implications of different oil vehicles used in depot neuroleptic treatment

On separate occasions two male schizophrenic inpatients were given intramuscular injections of equal amounts of perphenazine decanoate dissolved in sesame oil and Viscoleo, respectively. Substantially more even, but also lower perphenazine plasma concentrations were found within the dose intervals following the injections of perphenazine decanoate dissolved in sesame oil compared to the intervals following the Viscoleo-preparation. The occurrence of extrapyramidal side effects were consistent with the magnitude of the perphenazine plasma concentrations. The results support the importance of selecting an appropriate oil vehicle in a depot neuroleptic.