SPEX SPEX Pharmacology 2

Question 1

Which medication requires routine monitoring of serum drug levels due to its narrow therapeutic index?

Accepted Answer

Lithium

Answer

Lithium has a narrow therapeutic index, requiring regular serum level monitoring to prevent toxicity.

Question 2

A patient develops 'red man syndrome' during IV infusion. Which drug is responsible?

Accepted Answer

Vancomycin

Answer

Vancomycin infused too rapidly causes non-immune mast cell degranulation, leading to flushing and erythema known as red man syndrome.

Question 3

Which antihypertensive is contraindicated in bilateral renal artery stenosis?

Accepted Answer

ACE inhibitors

Answer

ACE inhibitors reduce efferent arteriolar tone, critically reducing GFR in bilateral renal artery stenosis and risking acute kidney injury.

Question 4

Which cytochrome P450 enzyme is primarily responsible for metabolizing warfarin and many other drugs?

Accepted Answer

CYP2C9

Answer

CYP2C9 is the primary enzyme responsible for S-warfarin metabolism, and its inhibition or induction significantly affects INR.

Question 5

What is the mechanism of action of statins in lowering LDL cholesterol?

Accepted Answer

Blocking HMG-CoA reductase

Answer

Statins inhibit HMG-CoA reductase, the rate-limiting enzyme in hepatic cholesterol synthesis, indirectly upregulating LDL receptors.

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