Gliclazide should not be used in type 1 diabetes mellitus. Use in type 2 diabetes mellitus is contraindicated in patients with ketoacidosis and in those with severe infections, trauma or other severe conditions where the drug is unlikely to control the hyperglycemia; insulin should be administered in such situations. Gliclazide may be suitable for use in patients with renal impairment, but that careful monitoring of blood-glucose concentration is essential. It should not be used in patients with severe renal impairment.