Which category of histamine H1 antagonists is noted for the alpha-adrenoreceptor-blocking effect?

Correct Answer: D

Rationale: The correct answer is D: Phenothiazines. Phenothiazines such as Diprazine and Promethazine are noted for their alpha-adrenoreceptor-blocking effect. This is due to their ability to block alpha-adrenergic receptors, leading to vasodilation and reduced blood pressure. Other choices (A, B, C) do not possess this specific alpha-adrenoreceptor-blocking effect and are not classified as histamine H1 antagonists known for this property. Therefore, the correct answer is D as phenothiazines exhibit the unique characteristic of alpha-adrenoreceptor-blocking effect among the given options.

Correct Answer: A

Rationale: The correct answer is A. HDL is a lipoprotein associated with a decreased risk of atherosclerosis and coronary artery disease due to its small amounts of cholesterol and triglycerides. It is also known as alpha-lipoprotein. Choice B is incorrect as it describes LDL, not HDL. Choice C is incorrect because high amounts of cholesterol are associated with LDL, not HDL. Choice D is incorrect as it describes chylomicrons, not HDL.

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: D

Rationale: The correct answer is D, as hypocalcemia in adults can result from various causes. Hypoparathyroidism leads to decreased parathyroid hormone and calcium levels. Vitamin D deficiency impairs calcium absorption. Renal failure and malabsorption can disrupt calcium balance. Therefore, all options A, B, and C contribute to hypocalcemia in adults. Other choices are incorrect because they do not comprehensively cover the major causes of hypocalcemia in adults.

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.