A 60-year-old female with diabetes is prescribed sitagliptin. Sitagliptin works by:

Correct Answer: A

Rationale: The correct answer is A because sitagliptin works by inhibiting the enzyme dipeptidyl peptidase-4 (DPP-4), which breaks down incretin hormones like GLP-1 and GIP. By inhibiting DPP-4, sitagliptin prolongs the action of these hormones, leading to increased insulin release and decreased glucagon secretion, ultimately lowering blood glucose levels. Choices B, C, and D are incorrect because sitagliptin does not directly increase insulin secretion from the pancreas, inhibit glucose absorption in the intestines, or increase renal glucose excretion.

Correct Answer: B

Rationale: The correct answer is B: Propranolol. Propranolol is a beta-blocker commonly prescribed for migraine prevention due to its ability to reduce the frequency and severity of migraine attacks by affecting blood vessels and neurotransmitters. Sumatriptan (A) is used for acute migraine treatment, not prevention. Ibuprofen (C) is an over-the-counter pain reliever for acute relief, not prevention. Lorazepam (D) is a benzodiazepine used for anxiety, not migraine prevention. Propranolol is the most appropriate choice for long-term migraine management.

Correct Answer: B

Rationale: The correct answer is B: Inhibiting HMG-CoA reductase in the liver. Atorvastatin is a statin drug that works by inhibiting the enzyme HMG-CoA reductase, which is involved in the production of cholesterol in the liver. By inhibiting this enzyme, atorvastatin reduces the synthesis of cholesterol in the liver, leading to lower levels of LDL cholesterol in the bloodstream. A: Inhibiting the reabsorption of cholesterol in the intestines - This is incorrect because atorvastatin primarily works in the liver, not in the intestines. C: Increasing HDL cholesterol levels - Atorvastatin is more effective at lowering LDL cholesterol levels rather than increasing HDL cholesterol levels. D: Increasing the excretion of cholesterol in the bile - Atorvastatin does not directly increase the excretion of cholesterol in the bile, it primarily acts in the liver to reduce cholesterol production.

Correct Answer: B

Rationale: The correct answer is B: Vitamin K. Warfarin is an anticoagulant that inhibits Vitamin K-dependent clotting factors. In the case of an overdose, administering Vitamin K helps replenish the depleted Vitamin K levels and restores the clotting factors, reversing the effects of warfarin. Protamine sulfate (A) is used to reverse heparin, not warfarin. Naloxone (C) is used to reverse opioid overdose. Flumazenil (D) is used to reverse benzodiazepine overdose.

Correct Answer: B

Rationale: The correct answer is B: N-acetylcysteine. N-acetylcysteine is used as an antidote for acetaminophen toxicity by replenishing glutathione stores in the liver, which helps to prevent liver damage. Naloxone (A) is an opioid antagonist, used for opioid overdose. Flumazenil (C) is a benzodiazepine antagonist, used for benzodiazepine overdose. Activated charcoal (D) is used to absorb ingested toxins in the gastrointestinal tract but is not specific to acetaminophen toxicity.