Concentrations of thioridazine and thioridazine metabolites in erythrocytes

Psychopharmacology (Berl). 1986;89(3):291-2. doi: 10.1007/BF00174361.


The concentrations of thioridazine and its main metabolites in erythrocytes from 61 thioridazine-treated patients were determined by gas-liquid chromatography. The mean and range of the erythrocyte concentrations, expressed as percentage of the corresponding plasma concentrations, were: thioridazine, 5.1% (2.0-10.6); side-chain sulfoxide, 5.6% (1.6-10.4); side-chain sulfone, 3.3% (1.1-6.8); ring sulfoxide 2.7% (0.8-4.9). The erythrocyte and plasma concentrations were significantly correlated. The erythrocyte/plasma concentration ratios, all the erythrocyte concentrations, but none of the plasma concentrations except ring sulfoxide were significantly positively correlated to the dose of thioridazine. The erythrocyte/plasma concentration ratio was not correlated to age. In vitro experiments indicated no clinically relevant erythrocyte-mediated oxidation of thioridazine.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Biotransformation
  • Erythrocytes / analysis*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Oxidation-Reduction
  • Thioridazine / analogs & derivatives
  • Thioridazine / blood*


  • Thioridazine