Which of the following drugs is commonly prescribed to treat acid reflux by reducing stomach acid production?

Correct Answer: A

Rationale: The correct answer is A: Omeprazole. Omeprazole is a proton pump inhibitor that reduces stomach acid production, making it effective in treating acid reflux. It works by blocking the enzyme responsible for acid production in the stomach. Loratadine (B) is an antihistamine used for allergies, Diphenhydramine (C) is also an antihistamine used for allergies and sleep aid, and Ibuprofen (D) is a nonsteroidal anti-inflammatory drug used for pain relief. These medications do not target stomach acid production and are not commonly prescribed for acid reflux.

Correct Answer: A

Rationale: Step 1: Amlodipine is a calcium channel blocker that inhibits calcium ion entry into smooth muscle cells. Step 2: By blocking calcium influx, amlodipine relaxes blood vessels, reducing blood pressure. Step 3: Enalapril is an ACE inhibitor, not a calcium channel blocker. Step 4: Clonidine is a centrally acting alpha-2 adrenergic agonist, not a calcium channel blocker. Step 5: Hydrochlorothiazide is a thiazide diuretic, not a calcium channel blocker.

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: C

Rationale: The correct answer is C: Inhibiting the If current in the sinoatrial node. Ivabradine is a selective inhibitor of the If current in the sinoatrial node, which results in lowering the heart rate without affecting other parameters like contractility or blood pressure. By reducing the If current, ivabradine slows down the heart rate, making it an effective treatment for heart failure patients. Explanation of other choices: A: Increasing the heart rate - This is incorrect because ivabradine actually decreases the heart rate. B: Blocking beta-adrenergic receptors - This is incorrect as ivabradine works through a different mechanism by inhibiting the If current. D: Increasing myocardial contractility - This is incorrect because ivabradine primarily targets heart rate and does not directly affect myocardial contractility.

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.