Retrospective evaluation of the effect of omeprazole on clozapine metabolism
- 134 Downloads
Objective: To study the effect of the replacement of omeprazole by pantoprazole on clozapine metabolism in 13 psychiatric patients, who used both clozapine and omeprazole.
Method: Retrospective study of the medical files.
Results: In comparison to smokers, a significant rise of the serum clozapine levels was observed in all non-smoking patients, whilst the daily dose of clozapine remained unchanged. This effect was probably caused by the discontinuation of enzyme induction of the cytochrome P450 enzyme 1A2 by omeprazole in non-smokers, whereas CYP1A2 remained induced in patients who smoked.
Conclusion: Omeprazole only influenced clozapine metabolism in non-smokers. In none of the patients an adjustment of the clozapine dose was required.
Unable to display preview. Download preview PDF.
- 1.Brøsen K. Drug-metabolizing enzymes and therapeutic drug monitoring in psychiatry. Ther Drug Monit 1996; 18: 393–6.Google Scholar
- 2.Desai HD, Seabolt J, Jann MW. Smoking in patients receiving psychotropic medications: a pharmacokinetic perspective. CNS Drugs 2001; 15: 469–94.Google Scholar
- 3.Meyer UA. Metabolic interactions of the proton-pump inhibitors lansoprazole, omeprazole and pantoprazole with other drugs. Eur J Gastroenterol 1996; 8(Suppl 1): S21-S25.Google Scholar
- 4.Humphries TJ, Merritt GJ. Review article: drug interactions with agents used to treat acid-related diseases. Aliment Pharmacol Ther 1999; 13(Suppl 3): 18–26.Google Scholar
- 5.Sterrenburg-van de Nieuwegiessen CM, Loonen AJM, Bakker JB. Polyfarmacie en irrationele combinaties van psychofarmaca bij verblijfspatiënten in het APZ: kunstfout of onvermijdelijk? [Polypharmacy and irrational combinations of psychotropics in chronic inpatients.] Tijdschr Psych 2000; 42: 565–74.Google Scholar
- 6.Seppälä NH, Leinonen EV, Lehtonen ML, Kivistö KT. Clozapine serum concentrations are lower in smoking than in non-smoking schizophrenic patients. Pharmacol Toxicol 1999; 85: 244–6.Google Scholar