Rifampicin reduces the levels and blood glucose lowering effects of
tolbutamide, gliclazide,
chlorpropamide (single case) and glibenclamide (
glyburide), and to a lesser extent
glimepiride,
glipizide and glymidine.
Rifampicin also reduces the AUC and effects of
repaglinide, and possibly
nateglinide.
Rifampicin reduces the AUCs of pioglitazone and rosiglitazone by about 50%, which could be clinically relevant.
Monitor the outcome of concurrent use on blood sugar levels and adjust the antidiabetic treatment accordingly. In many cases an increase in the dose of the antidiabetic seems likely to be needed.