May potentiate blood glucose-lowering effect w/ oral antidiabetics, insulin, ACE inhibitors, coumarin derivatives, quinolones, sulfonamides, tetracyclines, chloramphenicol, MAOIs, cyclophosphamide, fibrates, guanethidine, high dose pentoxifylline, salicylates, phenylbutazone, sulfinpyrazone & probenecid. May weaken blood glucose-lowering action w/ acetazolamide, corticosteroids, estrogens, progesterone, barbiturates, diuretics, epinephrine & other sympathomimetics, high dose of nicotinic acid, phenothiazines & phenytoin. May either potentiate or weaken the effect w/ alcohol, β-blockers, H
2-receptor antagonists, clonidine & reserpine.