Probenecid and sulfinpyrazone are uricosuric drugs employed to decrease the body pool of urate in patients with tophaceous gout or in those with increasingly frequent gouty attacks. This consideration is:

Correct Answer: A

Rationale: The correct answer is A: TRUE. Probenecid and sulfinpyrazone are indeed uricosuric drugs used to decrease urate levels in patients with tophaceous gout or frequent gouty attacks. Probenecid works by inhibiting urate reabsorption in the kidneys, leading to increased urate excretion. Sulfinpyrazone also increases urate excretion. Choice B is incorrect because the statement is true. Choice C is incorrect as it implies all choices are correct, which is not the case. Choice D is incorrect as it states that none of the choices are correct, which is not true in this scenario.

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 Chloramphenicol is a broad-spectrum antibiotic that inhibits protein synthesis in bacteria, making it bacteriostatic. It affects both Gram-positive and Gram-negative microorganisms. Choice A is incorrect because chloramphenicol is bacteriostatic, not bactericidal. Choice B is incorrect because it influences both Gram-positive and Gram-negative bacteria. Choice C is incorrect because it also influences both types of bacteria and it is bacteriostatic, not bactericidal.

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.