If a diabetic patient being treated with an oral hypoglycemic agent, develops dilutional hyponatermia, which one of the following could be responsible for this effect -

Chlorpropamide is an oral antihyperglycemic agent used for the treatment of non-insulin-dependent diabetes mellitus (NIDDM). It belongs to the sulfonylurea class of insulin secretagogues, which act by stimulating b cells of the pancreas to release insulin. Sulfonylureas increase both basal insulin secretion and meal-stimulated insulin release. Medications in this class differ in their dose, rate of absorption, duration of action, route of elimination and binding site on their target pancreatic b cell receptor. Sulfonylureas also increase peripheral glucose utilization, decrease hepatic gluconeogenesis and may increase the number and sensitivity of insulin receptors. Sulfonylureas are associated with weight gain, though less so than insulin. Due to their mechanism of action, sulfonylureas may cause hypoglycemia and require consistent food intake to decrease this risk. The risk of hypoglycemia is increased in elderly, debilitated and malnourished individuals. Chlorpropamide is not recommended for the treatment of NIDDM as it increases blood pressure and the risk of retinopathy . Up to 80% of the single oral dose of chlorpropramide is metabolized, likely in the liver; 80-90% of the dose is excreted in urine as unchanged drug and metabolites. Renal and hepatic dysfunction may increase the risk of hypoglycemia. Chlorpropamide (CPM) has been repoed to produce impaired water excretion due to the enhancement of renal vasopressin (ADH) action and/or due to centrally enhanced ADH release, but it is still unknown for sure whether CPM gives rise to ADH release with a subsequent hyponatremia in diabetes mellitus . Ref - harrisons internal medicine 20e p824t, 2965 , pubmed.com