A 70-year-old male with hypertension and heart failure is prescribed hydralazine. Hydralazine works by:

Correct Answer: A

Rationale: The correct answer is A: Relaxing vascular smooth muscle, leading to vasodilation. Hydralazine is a direct-acting vasodilator that relaxes arterial smooth muscle, resulting in vasodilation, which decreases systemic vascular resistance and blood pressure. This mechanism of action makes it beneficial in conditions like hypertension and heart failure. Choice B is incorrect as hydralazine does not block beta-1 adrenergic receptors in the heart. Choice C is incorrect because hydralazine does not inhibit the action of aldosterone. Choice D is incorrect as hydralazine does not directly affect the excretion of sodium and water in the kidneys.

Correct Answer: A

Rationale: The correct answer is A: Blocking calcium channels in the blood vessels. Nifedipine is a calcium channel blocker that works by inhibiting the influx of calcium ions into vascular smooth muscle cells, leading to vasodilation and decreased peripheral resistance. This reduces blood pressure in hypertensive patients. Choice B (Stimulating beta-1 adrenergic receptors) is incorrect because nifedipine does not act on adrenergic receptors. Choice C (Blocking the action of angiotensin II) is incorrect as nifedipine does not target the renin-angiotensin system. Choice D (Inhibiting aldosterone secretion from the adrenal glands) is incorrect as nifedipine does not directly affect aldosterone production.

Correct Answer: A

Rationale: The correct answer is A: Prednisone. Prednisone is a corticosteroid that works by reducing inflammation and suppressing the immune system, making it effective in treating conditions like asthma and rheumatoid arthritis. Lorazepam, Omeprazole, and Diazepam are not corticosteroids and do not have anti-inflammatory properties. Lorazepam and Diazepam are benzodiazepines used for anxiety and seizures, while Omeprazole is a proton pump inhibitor used for reducing stomach acid.

Correct Answer: B

Rationale: Amiodarone is the correct answer as it is a potent antiarrhythmic medication that works by inhibiting potassium channels, prolonging action potential duration. This helps in controlling various types of arrhythmias effectively. Lidocaine (A) works by blocking sodium channels, not potassium channels. Atenolol (C) is a beta-blocker that affects adrenergic receptors, not potassium channels. Verapamil (D) is a calcium channel blocker, which does not target potassium channels. Therefore, B is the correct choice for treating arrhythmias by inhibiting potassium channels.

Correct Answer: A

Rationale: The correct answer is A: Blocking the action of angiotensin II at its receptor. Valsartan is an angiotensin II receptor blocker (ARB) that works by binding to angiotensin II receptors, preventing angiotensin II from exerting its vasoconstrictive and aldosterone-stimulating effects. By blocking angiotensin II, valsartan helps dilate blood vessels, reduce blood pressure, and decrease the workload on the heart. Choices B, C, and D are incorrect because valsartan does not inhibit the conversion of angiotensin I to angiotensin II (choice B), inhibit aldosterone release (choice C), or directly increase sodium excretion in the kidneys (choice D).