Preoperative Medication Order for Pheochromocytoma Management

The correct order for preoperative medication administration in pheochromocytoma is alpha-blockers followed by beta-blockers (option b). 1, 2

Rationale for Alpha-Blockers First

Alpha-adrenergic blockade must be initiated 7-14 days before surgery with gradually increasing dosages to control blood pressure and prevent perioperative complications 1, 2
Alpha-blockers are the primary treatment to control symptoms and signs of catecholamine excess and prevent complications during therapeutic interventions 1
Both selective α1-blockers (doxazosin, prazosin, terazosin) and non-selective blockers (phenoxybenzamine) are effective options for preoperative preparation 2
The FDA label for phenoxybenzamine specifically indicates its use in pheochromocytoma to control episodes of hypertension and sweating 3

Beta-blockers should only be added after adequate alpha blockade to control tachycardia 2, 3
Monotherapy with beta-adrenergic blockers can elicit hypertension and is contraindicated in pheochromocytoma 1
Beta-blockers are typically added when tachycardia occurs during alpha-adrenergic blockade 1
The FDA label for phenoxybenzamine states: "If tachycardia is excessive, it may be necessary to use a beta-blocking agent concomitantly" 3

Starting beta-blockers before alpha-blockers can lead to unopposed alpha-adrenergic stimulation, resulting in severe hypertension 1, 2
This incorrect sequence can precipitate a hypertensive crisis during surgery 2
The American College of Cardiology emphasizes that beta blockade should precede vasodilator administration to prevent reflex tachycardia 1

Alpha-blockers should be started at least 7-14 days preoperatively with gradually increasing dosages until blood pressure targets are achieved (<130/80 mmHg supine) 1, 2
After establishing adequate alpha blockade, beta-blockers may be added to control tachycardia if needed 1, 2
High-sodium diet and administration of 1-2 liters of saline 24 hours prior to surgery, along with compressive stockings, should be employed to reduce the risk of orthostatic and postoperative hypotension 1, 2
Calcium channel blockers can be used as an adjunct to alpha-blockers for refractory hypertension or as monotherapy in cases with normal to mildly elevated blood pressure 1, 2

Metyrosine, which inhibits tyrosine hydroxylase and thereby catecholamine biosynthesis, can be used as an add-on medication where available 1, 4
Studies have shown that combining alpha-metyrosine with alpha-blockade results in better blood pressure control and less need for antihypertensive medication during surgery 4, 5
Diuretics are not part of the standard preoperative preparation for pheochromocytoma and could potentially worsen intravascular volume depletion 2