Potentiated blood sugar-lowering effect w/ insulin, oral antidiabetics, ACE inhibitors, allopurinol, anabolic steroids & male sex hormones, chloramphenicol, coumarin derivative, cyclophosphamide, disopyramide, fenfluramine, fenyramidol, fibrates, fluoxetine, guanethidine, ifosfamide, MAOIs, miconazole, p-aminosalicylic acid, high dose parenteral pentoxifylline, oxyphenbutazone, probenecid, quinolones, salicylates, sulfinpyrazone, sulfonamides, tetracyclines, tritoqualine, trofosfamide. Weakened blood sugar-lowering effect w/ acetazolamide, barbiturates, corticosteroids, diazoxide, diuretics, epinephrine (adrenaline) & other sympathomimetic agents, glucagon, laxatives (after protracted use), high dose nicotinic acid, oestrogens & progestogens, phenothiazines, phenytoin, rifampicin, thyroid hormones. Potentiated or weakened blood sugar-lowering effect w/ H
2-receptor antagonists, clonidine & reserpine. Decreased glucose tolerance & increased tendency to hypoglycemia w/ β-blockers.