No inhibition of cytochrome P450 activities in human liver microsomes by sulpiride, an antipsychotic drug

Biol Pharm Bull. 2005 Jan;28(1):188-91. doi: 10.1248/bpb.28.188.


The effects of sulpiride, an antipsychotic drug, on cytochrome P450 (CYP) activities in human liver microsomes were investigated. Sulpiride at 50 or 500 microM concentration neither inhibited nor stimulated CYP1A2-mediated 7-ethoxyresorufin O-deethylation, CYP2C9-mediated tolbutamide hydroxylation, CYP2C19-mediated S-mephenytoin 4'-hydroxylation, CYP2D6-mediated debrisoquine 4-hydroxylation, CYP2E1-mediated chlorzoxazone 6-hydroxylation, CYP3A4-mediated nifedipine oxidation, or CYP3A4-mediated testosterone 6beta-hydroxylation. The free fractions of sulpiride in the incubation mixture estimated by ultracentrifugation were more than 90.5%. These results suggest that sulpiride would not cause clinically significant interactions with other drugs, which are metabolized by CYPs, via the inhibition of metabolism.

Publication types

  • Comparative Study

MeSH terms

  • Antipsychotic Agents / pharmacology*
  • Cytochrome P-450 Enzyme Inhibitors
  • Cytochrome P-450 Enzyme System / metabolism*
  • Enzyme Inhibitors / pharmacology
  • Humans
  • Microsomes, Liver / drug effects*
  • Microsomes, Liver / enzymology*
  • Sulpiride / pharmacology*


  • Antipsychotic Agents
  • Cytochrome P-450 Enzyme Inhibitors
  • Enzyme Inhibitors
  • Sulpiride
  • Cytochrome P-450 Enzyme System