Which of the following medications is used to prevent blood clots by inhibiting platelet aggregation?

Correct Answer: C

Rationale: The correct answer is Clopidogrel (Choice C) because it is an antiplatelet medication that inhibits platelet aggregation, preventing blood clots. Aspirin (Choice A) also inhibits platelet aggregation but is not as specific as Clopidogrel. Warfarin (Choice B) is an anticoagulant that works by inhibiting the synthesis of clotting factors, not platelet aggregation. Enoxaparin (Choice D) is a low molecular weight heparin that works by inhibiting clot formation through a different mechanism than platelet aggregation. Therefore, Clopidogrel is the most appropriate choice for preventing blood clots by targeting platelet aggregation specifically.

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: Blocking beta-1 adrenergic receptors in the heart. Atenolol is a beta-blocker that primarily acts on beta-1 receptors in the heart, reducing heart rate and blood pressure. This helps in managing hypertension. Beta-2 receptors are predominantly found in the lungs, so choice B is incorrect. Choice C refers to calcium channel blockers, not atenolol. Choice D is related to diuretics, not beta-blockers like atenolol. Thus, the correct answer is A due to atenolol's specific action on beta-1 receptors in the heart.

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.