Causes severe hypoglycemia Diazoxide Diazoxide is a direct acting aeriolar dilator. Diazoxide causes aeriolar dilatation with little effect on veins. Diazoxide prevents smooth muscle contraction and relaxes the aerioles Diazoxide is a potassium channel activator which causes local relaxation in smooth muscle by increasing membrane permeability to potassium ions. This switches off voltage gated calcium ion channel which inhibits the generation of action potential. When used as an intravenous antihypeensive agent diazoxide causes excessive hypotension. Diazoxide was formerlyused as an intravenous bolus dose for the at of hypeensive emergencies. But the dangers of excessive hypotension are now recognized to outweigh the benefit, and its emergency use is obsolete. Hypotension due to diazoxide has resulted in stroke and myocardial infarction. - The reflex sympathetic response due to hypotension can provoke angina, electrocardiographic evidence of ischemia and cardiac failure in patients with ischemic hea disease and diazoxide should be avoided in this situation. Diazoxide produces hyperglycemia by increasing insulin secretion, therefore it is used to treat various forms of hypoglycemia Diazoxide activates the same potassium channel in the pancreatic islet cells that is blocked by sulfonylureas. SullOnylureas close the potassium channels and increase insulin secretion whereas diazoxide opens the potassium channel in pancreatic islet cells and decrease insulin secretion. Due to its hyperglycemic action it is a useful drug for patients with chronic hypoglycemia from excess endogenous insulin secretion, either from an iselt cell tumour (insulinoma) or islet cell hyperplasia. According to Lawerence Diazoxide stimulates the ATP dependent r channel that is blocked by the sulphonylureas. Therefore its chronic use as an antihypeensive agent is precluded by the development of diabetes. Indeed its use in therapeutics should now be confined to rare indication of treating hypoglycemia due to islet cell tumour (insulinoma). Diazoxide is chemically related to thiazide diuretics. But in contrast to the structurally related thiazide diuretics, diazoxide causes renal salt and water retention.