Gliben appears to lower the blood glucose acutely by stimulating the release of insulin from the pancreas, an effect dependent upon functioning beta cells in the pancreatic islets. The mechanism by which Gliben lowers blood glucose during long-term administration has not been clearly established. With chronic administration in Type II diabetic patients, the blood glucose lowering effect persists despite a gradual decline in the insulin secretory response to the drug. Extra pancreatic effects may play a part in the mechanism of action of oral sulfonylurea hypoglycemia drugs.

Side-effects include skin rashes, photosensitivity, diarrhoea, nausea, vomiting, epigastric pain, feeling of gastric fullness, dizziness, headache, weakness, fever, hypoglycemia reactions and paraesthesia. Eosinophilia, cholestasis, hepatitis, jaundice, blood disorders including leucopenia, thrombocytopenia, aplastic anaemia, pancytopenia, haemolytic anaemia and agranulocytosis may occur. The incidence of hypoglycemia can be reduced if Gliben is taken with or immediately after a meal. Transient visual disturbances may occur at the commencement of treatment. Intolerance to alcohol may occur. Adjustment of dosage of Gliben may be required in patients suffering from recurrent infections, trauma, shock or after anaesthesia. When major surgery is to be performed, Gliben should be substituted with insulin therapy.