Protease inhibitors are predicted to inhibit the
metabolism of
tacrolimus and increase its blood levels. Case reports have described this interaction with lopinavir, nelfinavir and saquinavir/ritonavir.
When
protease inhibitors are given to patients taking
tacrolimus, careful monitoring and probably a reduction in the dose of
tacrolimus is required. Note that in one case
tacrolimus was dosed just once weekly to achieve appropriate levels.