May diminish hypoglycaemic effects w/ epinephrine, aminoglutethimide, chlorpromazine, corticosteroids, diazoxide, OCs, rifamycins & thiazide diuretics. Increase hypoglycaemic effect w/ ACE inhibitors, alcohol, allopurinol, some analgesics (azapropazone, phenylbutazone & salicylates), azole antifungals (fluconazole, ketoconazole & miconazole), chloramphenicol, cimetidine, clofibrate & related compounds, coumarin anticoagulants, halofenate, heparin, MAOIs, octreotide, ranitidine, sulfinpyrazone, sulfonamides (including co-trimoxazole), tetracyclines, TCA & thyroid hormones; β-blockers.