All of the following statements regarding diuretics are true EXCEPT:

Correct Answer: C

Rationale: The correct answer is C because ibuprofen is a nonsteroidal anti-inflammatory drug (NSAID) that can reduce the antihypertensive effect of diuretics like chlorthalidone. Ibuprofen can lead to sodium and water retention, counteracting the diuretic's effects. Choices A, B, and D are true statements. A is true because furosemide can cause hypokalemia, increasing the risk of digitalis toxicity. B is true as chlorthalidone can decrease lithium excretion, potentially leading to lithium toxicity. D is true because chlorthalidone has a longer duration of action compared to furosemide due to its longer half-life.

Correct Answer: D

Rationale: The correct answer is D because fluoroquinolones are broad-spectrum antibiotics effective against a variety of Gram-negative and Gram-positive microorganisms, including Mycoplasmas and Chlamydiae. Fluoroquinolones work by targeting bacterial DNA gyrase and topoisomerase IV, which are essential for DNA replication. This mechanism of action allows fluoroquinolones to inhibit the growth of a wide range of bacteria. Choices A, B, and C are incorrect because fluoroquinolones are not limited to only Gram-negative or Gram-positive microorganisms, but rather have activity against both types of bacteria, making them effective against a diverse range of pathogens.

Correct Answer: A

Rationale: The correct answer is A: Didanosine. Nucleoside reverse transcriptase inhibitors (NRTIs) are a class of antiretroviral drugs used to treat HIV/AIDS. Didanosine is an NRTI that inhibits the reverse transcriptase enzyme, crucial for HIV replication. Gancyclovir is a nucleoside analog used to treat viral infections but not specifically NRTIs. Nevirapine is a non-nucleoside reverse transcriptase inhibitor. Vidarabine is a nucleoside analog antiviral drug, but it is not classified as an NRTI. Overall, only Didanosine belongs to the NRTI class of drugs.

Correct Answer: C

Rationale: The correct answer is C: Decreased myocardial remodeling. Beta-blockers decrease the workload of the heart by reducing heart rate and contractility, which in turn decreases myocardial oxygen demand and reduces the risk of further damage to the heart muscle post-myocardial infarction. This leads to a decrease in adverse remodeling of the heart, improving overall cardiac function and reducing mortality. Incorrect Choices: A: Increased myocardial oxygen supply - Beta-blockers do not directly increase myocardial oxygen supply but rather decrease oxygen demand. B: Decreased atrioventricular conduction - While beta-blockers can slow atrioventricular conduction, this is not the primary mechanism for mortality reduction in myocardial infarction. D: Increased systemic vascular resistance - Beta-blockers actually decrease systemic vascular resistance, which can be beneficial in certain conditions but is not the primary reason for mortality reduction in myocardial infarction.

Correct Answer: B

Rationale: The correct answer is B: Propranolol. Propranolol is a beta-blocker that can be used for rate control in atrial fibrillation. It works by blocking the effects of adrenaline on the heart, slowing the heart rate and reducing the force of contraction. In this case, the patient has atrial fibrillation with a rapid ventricular response, and propranolol can help slow the heart rate to a more appropriate level. A: Digoxin is primarily used for rate control in patients with heart failure, not as the first-line agent for atrial fibrillation with a rapid ventricular response. C: Verapamil is a calcium channel blocker that can also be used for rate control in atrial fibrillation, but beta-blockers are generally preferred in patients with concomitant peripheral artery disease. D: Lidocaine is a local anesthetic and antiarrhythmic agent used for ventricular arrhythmias, not appropriate for atrial fibrillation.