In vitro- undersøgelser viser, at irbesartan primært oxideres af cytokrom P450 enzymet CYP2C9. Isoenzym CYP3A4 har kun ubetydelig effekt.
In vitro studies indicate that irbesartan is primarily oxidised by the cytochrome P450 enzyme CYP2C9; isoenzyme CYP3A4 has negligible effect.