Which class of drugs is used to reduce the risk of blood clot formation in patients with atrial fibrillation?

Correct Answer: C

Rationale: The correct answer is C: Anticoagulants. Anticoagulants are specifically designed to reduce the risk of blood clot formation by inhibiting the clotting factors in the blood. Patients with atrial fibrillation are at an increased risk of developing blood clots due to irregular heartbeats, making anticoagulants the most appropriate class of drugs for this condition. ACE inhibitors (A) are used to treat high blood pressure, not specifically for preventing blood clots. Antiplatelets (B) work by preventing platelets from sticking together, but they are not as effective as anticoagulants for reducing the risk of blood clots in atrial fibrillation. Beta-blockers (D) are used to manage heart rate and blood pressure in atrial fibrillation, but they do not directly target blood clot formation.

Correct Answer: B

Rationale: The correct answer is B because salbutamol is a beta-2 adrenergic receptor agonist, which leads to bronchodilation by relaxing bronchial smooth muscle. This mechanism helps to relieve bronchoconstriction in asthma. Option A is incorrect as leukotriene receptors are not targeted by salbutamol. Option C is incorrect because salbutamol does not inhibit histamine release. Option D is incorrect as salbutamol does not increase mucus production; in fact, it may help reduce mucus secretion by improving airflow.

Correct Answer: A

Rationale: The correct answer is A: Blocking histamine receptors in the brain. Hydroxyzine is a first-generation antihistamine that exerts its effects by blocking histamine receptors, leading to its antihistaminic, sedative, and anxiolytic properties. The other choices (B, C, and D) are incorrect because hydroxyzine does not primarily affect serotonin levels, acetylcholine receptors, or opioid receptors in the brain. Serotonin reuptake inhibitors, anticholinergics, and opioids work through different mechanisms compared to hydroxyzine.

Correct Answer: A

Rationale: The correct answer is A: Methotrexate. Methotrexate is a disease-modifying antirheumatic drug (DMARD) that suppresses the immune system to reduce inflammation in rheumatoid arthritis. It helps to slow down the progression of the disease and prevent joint damage. Prednisone (B) is a corticosteroid that helps reduce inflammation but does not suppress the immune system in the same way as Methotrexate. Aspirin (C) is a nonsteroidal anti-inflammatory drug (NSAID) that helps with pain and inflammation but does not alter the immune response. Hydroxychloroquine (D) is an antimalarial drug that can be used to treat rheumatoid arthritis but does not primarily suppress the immune system like Methotrexate.

Correct Answer: B

Rationale: The correct answer is B: Improving insulin sensitivity in peripheral tissues. Metformin enhances the response of peripheral tissues to insulin, allowing for better utilization of glucose, reducing blood sugar levels. This mechanism helps to decrease insulin resistance, a key feature in type 2 diabetes. Other choices are incorrect because metformin does not directly increase insulin secretion from the pancreas (choice A), inhibit glucose absorption in the intestine (choice C), or increase the excretion of glucose in the urine (choice D). These mechanisms do not align with how metformin primarily works to improve glucose control in type 2 diabetes.