Metformin: Interacts w/ cimetidine. May partly offset the anti-hyperglycemic action w/ drugs w/ hyperglycemic potential (eg, thiazides, corticosteroids). Potentiated action on lactate metabolism as well as anti-hyperglycemic effect w/ alcohol. Increased plasma levels w/ furosemide & nifedipine. Reduced absorption w/ acarbose & guar gum. Glimepiride: Hypoglycemia 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, para-aminosalicylic acid, pentoxifylline (high dose parenteral), phenylbutazone, azapropazone, oxyphenbutazone, probenecid, quinolones, salicylates, sulfinpyrazone, sulfonamides, tetracyclines, tritoqualine, trofosfamide. Hyperglycemia w/ acetazolamide, barbiturates, corticosteroids, diazoxide, diuretics, epinephrine (adrenaline) & other sympathomimetic agents, glucagons, laxatives (after protracted use), nicotinic acid (in high doses), estrogens & progestogens, phenothiazines, phenytoin, rifampicin, thyroid hormones. May lead to either potentiation or weakening of blood sugar-lowering effect w/ H
2-receptor antagonists, clonidine & reserpine. May increase the tendency to hypoglycemia w/ β-blockers. May potentiate or weaken the effect of coumarin derivatives.