Olanzapro Drug Interactions

The central effects of other CNS depressants, including alcohol may be enhanced by olanzapine. Olanzapine may antagonize the effects of dopaminergics. Neutropenia may be more common when olanzapine is with valproate. There is a theoretical risk of QT prolongation when olanzapine is given with other drugs that are known to cause this effect.
The metabolism of olanzapine is mediated to some extent by the cytochrome P450 isoenzyme CYPIA2. Use with drugs that inhibit, induce or act as a substrate to this isoenzyme may affect plasma concentrations of olanzapine and a dose adjustment of olanzapine may be required. The CYPIA2 inhibitor fluvoxamine significantly inhibits the metabolism of olanzapine. The clearance of olanzapine is increased by tobacco, smoking and carbamazepine.