A 20-year-old woman comes to the emergency department after ingesting at least 30 tablets of an unknown drug. Initial physical examination shows no abnormalities. Thirty-six hours later, serum AST activity is 1500 U/L, and serum ALT activity is 2000 U/L. The drug this patient ingested is most likely which of the following?

Correct Answer: A

Rationale: Elevated AST and ALT (1500 and 2000 U/L) 36 hours post-ingestion indicate acute liver injury, characteristic of acetaminophen overdose. Acetaminophen is metabolized to NAPQI, which depletes glutathione and causes centrilobular hepatic necrosis if untreateAspirin causes salicylism (tinnitus, acidosis), chlorpheniramine sedation, ibuprofen GI upset, and prednisone (E) adrenal suppression—none primarily cause delayed hepatotoxicity like this.

Correct Answer: D

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: A

Rationale: The correct answer is A: Atorvastatin. Atorvastatin belongs to a class of drugs known as statins, which are highly effective in lowering LDL cholesterol levels by inhibiting the enzyme responsible for cholesterol production in the liver. This mechanism of action has been proven to significantly reduce LDL cholesterol levels in the blood. In contrast, choice B (Gemfibrozil) primarily targets triglycerides and has limited impact on LDL cholesterol. Choice C (Ezetimibe) works by blocking cholesterol absorption in the intestines but is not as potent as statins in lowering LDL cholesterol. Choice D (Cholestyramine) is a bile acid sequestrant that binds to bile acids in the intestines, but it is less effective than statins in lowering LDL cholesterol. Overall, Atorvastatin is the most effective choice for reducing LDL cholesterol levels due to its potent mechanism of action.

Correct Answer: C

Rationale: The correct answer is C: Acne. Tretinoin is a topical retinoid that is commonly used to treat acne. It works by promoting skin cell turnover and preventing the formation of new acne lesions. Tretinoin is not used for psoriasis (A), seborrheic dermatitis (B), or multiple sclerosis (D) as these conditions require different treatment approaches.

Correct Answer: B

Rationale: Step 1: Drugs with a narrow therapeutic index have a small range between the minimum effective dose and the minimum toxic dose. Step 2: Genetic variants affecting drug metabolism can lead to small increases or decreases in drug levels. Step 3: Small increases can cause toxicity, while small decreases can lead to therapeutic failure. Step 4: Therefore, statement B is true as it correctly describes the impact of genetic variants on drug metabolism for drugs with a narrow therapeutic index. Summary: Statement A is incorrect as not all statements are true. Statement C is incorrect as drugs like warfarin are indeed affected by CYP2C9. Statement D is incorrect as drugs with a high therapeutic index are less affected by altered metabolism compared to drugs with a narrow therapeutic index.