Which of the following drugs is an uricosuric agent:

Correct Answer: B

Rationale: The correct answer is B: Sulfinpyrazone. This drug is an uricosuric agent that works by increasing the excretion of uric acid in the urine, thereby reducing serum uric acid levels. Allopurinol (A) is a xanthine oxidase inhibitor that decreases uric acid production. Colchicine (C) is used for gout but does not directly impact uric acid levels. Indomethacin (D) is a nonsteroidal anti-inflammatory drug that can help with gout symptoms but does not affect uric acid excretion.

Correct Answer: A

Rationale: The correct answer is A: Osmotic diuretics. Osmotic diuretics are the least potent diuretics as they work by creating an osmotic force that prevents water reabsorption in the nephron, leading to increased urine output. Loop diuretics (B) are more potent as they act on the ascending loop of Henle. Thiazide diuretics (C) are also more potent as they act on the distal convoluted tubule. Potassium-sparing diuretics (D) are relatively less potent than loop and thiazide diuretics but are still more potent than osmotic diuretics.

Correct Answer: B

Rationale: The correct answer is B: Pancytopenia. Chloramphenicol is known to cause bone marrow suppression, leading to a decrease in red blood cells, white blood cells, and platelets. This results in pancytopenia, which can manifest as anemia, increased risk of infections, and easy bruising or bleeding. Nephrotoxicity (A), hepatotoxicity (C), and ototoxicity (D) are not common side effects of chloramphenicol. Pancytopenia is a well-documented adverse effect of this antibiotic due to its impact on bone marrow function.

Correct Answer: B

Rationale: The correct answer is B: Headache, dizziness, insomnia. Fluoroquinolones are known to cause central nervous system side effects such as headache, dizziness, and insomnia. These unwanted effects are commonly reported with the use of fluoroquinolones. Hallucinations (choice A) are not typically associated with fluoroquinolones. Hypertension (choice C) is not a common side effect of fluoroquinolones. Immunetoxicity (choice D) is a general term and not a specific unwanted effect of fluoroquinolones. Therefore, choice B is the correct answer due to the known side effects of fluoroquinolones on the central nervous system.

Correct Answer: A

Rationale: Acyclovir is an antiviral drug used to treat herpes infections, not influenza. Amantadine and Rimantadine are anti-influenza agents that target the influenza A virus. Interferons are proteins that help the immune system fight viruses, including influenza. Therefore, the correct answer is A (Acyclovir) because it is not used specifically to treat influenza infections.