Wuzhi capsule increased systemic exposure to methotrexate by inhibiting the expression of OAT1/3 and P-gp.

Background: Methotrexate (MTX) is an important anticancer agent and immunosuppressant with a narrow therapeutic window. Wuzhi capsule (WZC) is an extract of Schisandra which is widely used to treat liver diseases. Co-administration of MTX and WZC is common in the clinical setting, but research on the interaction between WZC and MTX is limited.