The manufacturers and the CSM in the UK warn that rifabutin
may also possibly reduce the effects of oral antidiabetics
, although this is likely to be to at lesser extent than rifampicin. Rifampicin has the following effects: 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.
reduces the AUC and effects of repaglinide, and possibly nateglinide.
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 may possibly be needed.