Diazoxide

Diazoxide is a pharmacologic agent that acts as a potassium channel opener, affecting both vascular smooth muscle and pancreatic beta cells. By opening ATP-sensitive potassium channels, it causes vascular smooth muscle relaxation and reduces peripheral resistance, providing rapid antihypertensive effects in select hypertensive emergencies. In pancreatic beta cells, the same mechanism hyperpolarizes the cell membrane and inhibits insulin release, making diazoxide useful in disorders of hyperinsulinism.

Medical uses include the acute management of hypersinsulinemic hypoglycemia, such as congenital hyperinsulinism and insulinoma-related hypoglycemia, where reduction of insulin secretion helps prevent recurrent episodes. It is also employed, via intravenous administration, as a vasodilator for severe, refractory hypertension in urgent settings. Brand names include Proglycem for oral use in hyperinsulinism and Hyperstat for IV use in hypertensive crises. Diazoxide is sometimes combined with a thiazide diuretic to counteract edema and with a beta-blocker to mitigate reflex tachycardia.

Adverse effects are common and include hyperglycemia, edema and fluid retention, tachycardia, nausea, and hirsutism with longer use. Because it lowers blood pressure and can raise glucose, patients require monitoring of blood pressure and blood glucose, especially in infants and those with diabetes or heart disease. Contraindications include hypersensitivity to diazoxide and conditions where further fluid overload or hypotension would be dangerous, such as certain advanced cardiac diseases. Caution is advised during pregnancy and lactation, and use should be guided by specialist supervision.