Which of the following medications is commonly used for the prevention of nausea and vomiting in patients undergoing chemotherapy?

Correct Answer: A

Rationale: The correct answer is A: Ondansetron. Ondansetron is a commonly used antiemetic medication that works by blocking serotonin receptors in the brain, thus preventing nausea and vomiting. It is specifically indicated for the prevention of chemotherapy-induced nausea and vomiting. Loperamide (B) is an antidiarrheal medication, Omeprazole (C) is a proton pump inhibitor used for acid reflux, and Dexamethasone (D) is a corticosteroid used for inflammation and immune suppression. These medications are not typically used for preventing nausea and vomiting in chemotherapy patients.

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: A

Rationale: The correct answer is A: Alprazolam. Alprazolam is a benzodiazepine commonly used for treating acute anxiety due to its fast onset of action. It works by enhancing the effects of GABA neurotransmitters, leading to calming effects. Citalopram and Venlafaxine are antidepressants used for long-term treatment of anxiety disorders, not for acute episodes. Zolpidem is a sedative-hypnotic mainly used for insomnia, not anxiety.

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.