Drug for management of hypertension in Phaeochromocytoma?

Ans. is 'a' i.e., Phenoxvbenzamine There are three methods used for the preoperative treatment of pheochromocytomao Once a pheochromocytoma is diagnosed, all patients should undergo a resection of the pheochromocvtoma following appropriate medical preparation.o Resecting a pheochromocytoma is a high-risk surgical procedure and an experienced surgeon/anesthesiologist team is required.o Some form ofpreoperative pharmacologic preparation is indicatedfor all patients with catecholamine-secreting neoplasms.Preoperative medical therapy is aimed at:o Controlling hypertension (including preventing a hypertensive crisis during surgery)o Volume expansiono In patients with undiagnosed pheochromocytomas who undergo surgery for other reasons (and who therefore have not undergone preoperative medical therapy), surgical mortality: rates are high due to lethal hypertensive crises, malignant arrhythmias, and multiorgan failure.Combined alpha- and beta-adrenergic blockadeo Combined alpha- and beta-adrenergic blockade is the most common approach to control blood pressure and prevent intraoperative hypertensive crises.Alpha-adrenergic blockadeo An alpha-adrenergic blocker is given 10 to 14 days preoperatively to normalize blood pressure and expand the contracted blood volume.o Phenoxvbenzamine is the preferred drug for preoperative preparation to control blood pressure and arrhythmia in most centers in the United States. It is an irreversible, long-acting, nonspecific alpha-adrenergic blocking agent.o The initial dose is 10 mg once or twice daily, and the dose is increased by 10 to 20 mg in divided doses every two to three days as needed to control blood pressure and spells.o The final dose of phenoxvbenzamine is typically between 20 and 100 mg daily.Beta-adrenergic blockadeo After adequate alpha-adrenergic blockade has been achieved, beta-adrenergic blockade is initiated, which typically occurs two to three days preoperatively.o The beta-adrenergic blocker should never be started first because blockade of vasodilator)' peripheral beta- adrenergic receptors with unopposed alpha-adrenergic receptor stimulation can lead to a further elevation in blood pressure.The alternatives to a and b adrenergic agents are calcium channel blockers and metyrosine.Calcium channel blockerso Although perioperative alpha-adrenergic blockade is widely recommended, a second regimen that has been utilized involves the administration of a calcium channel blocker.o Nicardipine is the most commonly used calcium channel blocker in this setting; the starting dose is 30 mg twice daily of the sustained release preparation.Metyrosineo Another approach involves the administration of metyrosine ialpha-methyl-para-tyrosine), which inhibits catecholamine synthesis.