Solve with reason and explain simply
Answer: B — Phentolamine ✅
The Question
Which drug is used for BP control in pheochromocytoma perioperatively?
What is Pheochromocytoma?
A tumor of the adrenal medulla that releases massive amounts of catecholamines (adrenaline + noradrenaline), causing dangerous spikes in blood pressure — especially during surgical manipulation of the tumor.
Why Phentolamine?
| Feature | Explanation |
|---|---|
| Drug class | Non-selective alpha blocker (blocks α1 and α2 receptors) |
| Action | Blocks the effect of catecholamines on blood vessels → prevents vasoconstriction → lowers BP |
| Speed | Acts rapidly and is reversible — ideal for acute intraoperative BP surges |
| Perfect fit | When the surgeon touches/removes the tumor, catecholamines flood the bloodstream. Phentolamine instantly blunts this response |
Why NOT the others?
| Option | Why Wrong |
|---|---|
| A — Labetalol | Alpha + beta blocker, but beta blockade should NOT be given before alpha blockade in pheo — it can worsen hypertension by leaving alpha receptors unopposed |
| C — Metoprolol | Pure beta blocker — same problem; used only after alpha blockade is established |
| D — Enalapril | ACE inhibitor — works on the renin-angiotensin system, not effective against catecholamine surges |
Simple Memory Trick
Pheo = Phentolamine (both start with "Ph") — block alpha first, always!
The classic perioperative sequence:
- Alpha blocker first (Phentolamine IV intraop, or Phenoxybenzamine preop)
- Beta blocker only after alpha blockade is established (to control reflex tachycardia)
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