# Tacrolimus: read the medication list by date

A new CYP3A inhibitor such as diltiazem can raise tacrolimus exposure without a dose change. Ask about prescription, nonprescription and herbal drugs and the exact start dates. Tremor, AKI, hyperkalemia or neurologic symptoms prompt urgent assessment, correctly timed drug levels and transplant-center contact. Check the last dose and blood-draw time before interpreting a trough. The transplant center may adjust or hold therapy; the PA should implement the coordinated plan rather than independently stopping immunosuppression. Infection, rejection, obstruction and hemodynamic injury remain in the differential.

[PROGRAF prescribing information](https://dailymed.nlm.nih.gov/dailymed/getFile.cfm?name=PROGRAF&setid=7f667de1-9dfa-4bd6-8ba0-15ee2d78873b)

Andrew Bland, MD, FACP, FAAP