Drug of choice for pheochromocytoma ?
**Core Concept**
Pheochromocytoma is a rare, usually benign tumor of the adrenal gland that produces excessive catecholamines, leading to hypertension, tachycardia, and other systemic symptoms. The primary goal of treatment is to control blood pressure and prevent life-threatening complications.
**Why the Correct Answer is Right**
The drug of choice for pheochromocytoma is a non-selective alpha and beta blocker, typically phenoxybenzamine. This medication works by blocking alpha receptors, which reduces peripheral vascular resistance and prevents a sudden increase in blood pressure, and beta receptors, which decreases heart rate and contractility. This approach is crucial in managing pheochromocytoma because alpha receptors are primarily responsible for the vasoconstriction seen in this condition. Once the blood pressure is controlled, a selective alpha blocker like doxazosin may be used to prevent orthostatic hypotension, and then a beta blocker like atenolol or metoprolol is added to control the heart rate.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not address the need for a non-selective alpha and beta blocker in the initial management of pheochromocytoma.
**Option B:** This option is incorrect because it does not provide a comprehensive approach to managing pheochromocytoma, which requires both alpha and beta blockade.
**Option C:** This option is incorrect because it is a selective alpha blocker and does not provide adequate beta blockade to control heart rate.
**Clinical Pearl / High-Yield Fact**
When managing pheochromocytoma, it's crucial to start with a non-selective alpha and beta blocker like phenoxybenzamine to control blood pressure, followed by a selective alpha blocker to prevent orthostatic hypotension, and finally a beta blocker to control heart rate.
**Correct Answer: C. Phenoxybenzamine**