Co-administration w/ inducers (eg, rifampicin) or inhibitors (eg, fluconazole) of CYP 2C9. Effects potentiated when used w/ insulin & other oral antidiabetics, ACE inhibitors, allopurinol, anabolic steroids & male sex hormones, chloramphenicol, coumarin derivatives, cyclophosphamide, disopyramide, fenfluramine, fenyramidol, fibrates, fluoxetine, guanethidine, ifosfamide, MAOIs, miconazole, fluconazole, p-aminosalicylic acid, pentoxifylline (high dose parenteral), phenylbutazone, azapropazone, oxyphenbutazone, probenecid, quinolones, salicylates, sulfinpyrazone, clarithromycin, sulfonamides, tetracyclines, tritoqualine, trofosfamide. Effects weakened when used w/ acetazolamide, barbiturates, corticosteroids, diazoxide, diuretics, epinephrine & other sympathomimetics, glucagon, laxatives (after protracted use), nicotinic acid (high dose), oestrogens & progestogens, phenothiazines, phenytoin, rifampicin, thyroid hormones. May either potentiate or weaken effects w/ H2
receptor antagonist, clonidine & reserpine, acute & chronic alcohol intake. β-blockers decrease glucose tolerance. Reduced absorption w/ colesevelam. Effect of coumarin derivatives may be potentiated or weakened.