Beri-beri is caused by the deficiency of:

Correct Answer: D

Rationale: The correct answer is D: Thiamine. Beri-beri is caused by a deficiency of thiamine (Vitamin B1), which is essential for energy metabolism and nerve function. Thiamine deficiency leads to symptoms like fatigue, muscle weakness, nerve damage, and heart problems. Riboflavin (A), Ascorbic acid (B), and Nicotinic acid (C) deficiencies do not directly cause Beri-beri. Riboflavin is important for energy production, Ascorbic acid is Vitamin C important for immunity, and Nicotinic acid is Vitamin B3 important for metabolism.

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: B

Rationale: The correct answer is B: Defective bone mineralization. Etidronate is a bisphosphonate used to treat osteoporosis by inhibiting bone resorption, leading to increased bone density. However, long-term use can result in defective bone mineralization, leading to brittle or weakened bones. A: Anorexia is not a known side effect of etidronate and is more commonly associated with other medications or medical conditions. C: Hypercalcemia is unlikely with etidronate use since it works to reduce calcium loss from bones. D: Cardiac arrhythmias are not a typical side effect of etidronate and are more commonly associated with other medications or underlying heart conditions.

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.