The drug is one of the most potent diuretics:

Correct Answer: B

Rationale: Step 1: Furosemide is a loop diuretic, which acts on the ascending loop of Henle to inhibit sodium and chloride reabsorption, leading to potent diuresis. Step 2: Loop diuretics like Furosemide are more potent compared to other diuretics like thiazides (Hydrochlorothiazide) or potassium-sparing diuretics (Amiloride). Step 3: Acetazolamide is a carbonic anhydrase inhibitor that works in the proximal tubule and has a different mechanism of action, making it less potent than loop diuretics. Step 4: Therefore, the correct answer is B, Furosemide, as it is a potent diuretic acting on the loop of Henle. Other choices are less potent due to their mechanisms of action and sites of action.

Correct Answer: A

Rationale: The correct answer is A because nausea, vomiting, diarrhea, and stomatitis are common side effects of Metronidazole. Hypertension and disturbances of peripheral blood circulation are not typically associated with Metronidazole use. Therefore, choice A is the only option that accurately reflects the unwanted effects of Metronidazole.

Correct Answer: B

Rationale: The correct answer is B: Zidovudine. Zidovudine is a nucleoside analog reverse transcriptase inhibitor used in the treatment of HIV infection. It works by inhibiting the reverse transcriptase enzyme, crucial for viral replication. Acyclovir (A) is used for herpes infections, Gancyclovir (C) for cytomegalovirus, and Trifluridine (D) for ocular herpes. They are not derivatives of nucleosides and are not used for HIV treatment.

Correct Answer: A

Rationale: The correct answer is A: Verapamil. Verapamil is a calcium channel blocker that can help prevent delayed cerebral ischemia by reducing vasospasm in the blood vessels in the brain. This is important in patients with blood in the subarachnoid space, as vasospasm can lead to decreased blood flow and subsequent ischemia. Isosorbide mononitrate (B) and Propranolol (C) are not typically used for preventing cerebral vasospasm. Dobutamine (D) is a positive inotrope and is not indicated for preventing cerebral vasospasm.

Correct Answer: B

Rationale: The correct answer is B: Amiodarone. Amiodarone is the most appropriate choice because it is a Class III antiarrhythmic drug that is effective in treating various types of arrhythmias, including ventricular and atrial arrhythmias. It works by prolonging the action potential duration and refractory period of cardiac tissue, helping to stabilize the heart's rhythm. Quinidine (A) is a Class I antiarrhythmic drug with potential side effects and limited efficacy. Verapamil (C) is a calcium channel blocker that is more suitable for treating certain types of supraventricular arrhythmias but not as effective for other types. Propranolol (D) is a beta-blocker that may be used for certain arrhythmias, but it is not as effective or versatile as amiodarone for treating various types of arrhythmias.