Indications: type 2 diabetes mellitus

Cautions: Sulfonylureas can encourage weight gain and should be prescribed only if poor control and symptoms persist despite adequate attempts at dieting; Caution is needed in the elderly and in patients with G6PD deficiency.

Contra-indications: Sulfonylureas should be avoided where possible in acute porphyria but Sulfonylureas are contra-indicated in the presence of ketoacidosis.

Hepatic impairment: Sulfonylureas should be avoided or a reduced dose should be used in severe hepatic impairment, because there is an increased risk of hypoglycaemia. Jaundice may occur.

Renal impairment: Sulfonylureas should be used with care in those with mild to moderate renal impairment, because of the hazard of hypoglycaemia; they should be avoided where possible in severe renal impairment.

Glipizide should also be avoided if the patient has both renal and hepatic impairment. If necessary, the short- acting drug tolbutamide can be used in renal impairment, as can gliclazide which is principally metabolised in the liver, but careful monitoring of blood-glucose concentration is essential; care is required to use the lowest dose that adequately controls blood glucose.

Pregnancy: The use of sulfonylureas in Pregnancy should generally be avoided because of the risk of neonatal hypoglycaemia; however, glibenclamide can be used during the second and third trimesters of pregnancy in women with gestational diabetes.

Breast-feeding: The use of sulfonylureas in breast- feeding: should be avoided because there is a theoretical possibility of hypoglycaemia in the infant.

Side Effects: of sulfonylureas are generally mild and infrequent and include gastro-intestinal disturbances such as nausea, vomiting, diarrhoea, and constipation.

Sulfonylureas can occasionally cause a disturbance in liver function, which may rarely lead to cholestatic jaundice, hepatitis, and hepatic failure. Hypersensitivity reactions can occur, usually in the first 6–8 weeks of therapy. They consist mainly of allergic skin reactions which progress rarely to erythema multiforme and exfoliative dermatitis, fever, and jaundice; Blood disorders are also rare but may include leucopenia, thrombocytopenia, agranulocytosis, pancytopenia, haemolytic anaemia, and aplastic anaemia.

Dose: Initially, 40–80 mg daily, adjusted according to response; up to 160 mg as a single dose, with breakfast; higher doses divided; max. 320 mg daily.