Clozapine and norclozapine pharmacokinetic interaction with pantoprazole

The concurrent intake of pantoprazole decreased the clozapine and norclozapine exposure, which was explained by the pantoprazole's impact on gastric acidity and clozapine absorption rather than on metabolizing enzymes. The interaction was not clinically relevant at low doses; however, clinicians should consider concomitant acid-reducing agents when interpreting clozapine therapeutic drug monitoring results.