Efavirenz and Tacrolimus interaction
Efavirenz and Tacrolimus: both prescribing labels describe an interaction that usually calls for monitoring, a dose change, or spacing the doses.
Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.
What the FDA labels say
From the Efavirenz label · effective 2024-03-31
QT Prolonging Drugs There is limited information available on the potential for a pharmacodynamic interaction between efavirenz and drugs that prolong the QTc interval.
Immunosuppressants: Cyclosporine, tacrolimus, sirolimus and others metabolized by CYP3A ↓ immunosuppressant Dose adjustments of the immunosuppressant may be required.
Close monitoring of immunosuppressant concentrations for at least 2 weeks (until stable concentrations are reached) is recommended when starting or stopping treatment with efavirenz.
From the Tacrolimus (ASTAGRAF XL) label · effective 2026-01-14
The risk for nephrotoxicity may increase when ASTAGRAF XL is concomitantly administered with CYP3A inhibitors (by increasing tacrolimus whole blood concentrations) or drugs associated with nephrotoxicity (e.g., aminoglycosides, ganciclovir, amphotericin B, cisplatin, nucleotide reverse transcriptase inhibitors, protease inhibitors).
Risk of Rejection with Strong CYP3A Inducers and Risk of Serious Adverse Reactions with Strong CYP3A Inhibitors The concomitant use of strong CYP3A inducers may increase the metabolism of tacrolimus, leading to lower whole blood trough concentrations and greater risk of rejection.
In contrast, the concomitant use of strong CYP3A inhibitors may decrease the metabolism of tacrolimus, leading to higher whole blood trough concentrations and greater risk of serious adverse reactions (e.g., neurotoxicity, QT prolongation) [see Warnings and Precautions ( 5.7 , 5.11 )] .
Therefore, adjust ASTAGRAF XL dose and monitor tacrolimus whole blood trough concentrations when co-administering ASTAGRAF XL with strong CYP3A inhibitors (e.g., including, but not limited to, telaprevir, boceprevir, ritonavir, ketoconazole, itraconazole, voriconazole, clarithromycin) or strong CYP3A inducers (e.g., including, but not limited to, rifampin, rifabutin)…
A rapid, sharp rise in tacrolimus levels has been reported after co-administration with a strong CYP3A4 inhibitor, clarithromycin, despite an initial reduction of tacrolimus dose.
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.