Pharmacokinetics of antipsychotic drugs in man.

Variability in the outcome of treatment with antipsychotic drugs may be due to differences in compliance and to variations in pharmacokinetics and concentration-response relationships at the receptor level. Among the various chemical classes of neuroleptics, the butyrophenones, the phenothiazines, and the thioxanthenes have similar pharmacokinetics, and show larger inter-individual variations in plasma drug levels after oral than after intramuscular doses. Compared to the "classical" neuroleptics, the more water-soluble benzamide derivatives have significantly shorter elimination half-lives, and show smaller inter-patient variations in plasma level: dose ratios at steady state.