Which category of histamine H1 antagonists is noted for the highest local anesthetic effect?

Correct Answer: D

Rationale: The correct answer is D, Phenothiazines such as Promethazine, because they have the highest local anesthetic effect among histamine H1 antagonists. This is due to their structural properties that allow them to interact with sodium channels and block nerve impulses effectively. Phenothiazines have a bulky side chain that enhances their local anesthetic properties. A, Alkylamines like Brompheniramine, are known for their sedative effects rather than local anesthetic properties. B, Piperidines including Loratadine and Fexofenadine, are mainly used for their antihistaminic effects and do not exhibit strong local anesthetic properties. C, Ethylenediamines like Suprastine, are not recognized for their local anesthetic effects but rather for their antihistaminic actions. In summary, Phenothiazines stand out as having the highest local anesthetic effect compared to the other categories of histamine H

Correct Answer: D

Rationale: The correct answer is D because chylomicron is a large lipoprotein particle produced in the small intestine absorbing dietary fats. This lipoprotein transports lipids to adipose tissue where they are broken down by lipoprotein lipase. The other choices are incorrect because: A: Chylomicron does not contain small amounts of cholesterol and triglycerides, nor is it associated with decreased risk of atherosclerosis. B: Chylomicron carries dietary lipids, not cholesterol from the liver to tissues. C: Chylomicron does not contain high amounts of cholesterol and is not associated with increased risk of atherosclerosis.

Correct Answer: C

Rationale: The correct answer is C: Colchicine. Uricosuric drugs increase excretion of uric acid in the urine to treat gout. Colchicine is not a uricosuric drug; it is used to treat gout flares by reducing inflammation. Probenecid and Sulfinpyrazone are uricosuric drugs that work by inhibiting uric acid reabsorption in the kidneys. Aspirin at high dosages can compete with uric acid for excretion in the kidneys, so it can also have uricosuric effects.

Correct Answer: C

Rationale: Rationale: C. Renal failure and malabsorption are not major causes of hypercalcemia. - Hyperparathyroidism leads to increased calcium levels due to overproduction of PTH. - Cancer with or without bone metastases can release calcium into the bloodstream. - Hypervitaminosis D can cause hypercalcemia by increasing intestinal calcium absorption. Renal failure and malabsorption do not directly increase calcium levels.

Correct Answer: A

Rationale: The correct answer is A: Osmotic diuretics. These agents are not absorbed when given orally due to their large molecular size, which prevents them from passing through the gastrointestinal mucosa. They must be administered parenterally for effective absorption and distribution in the body to exert their diuretic effects. Loop diuretics (B) are well-absorbed orally in the gastrointestinal tract. Thiazide diuretics (C) are also absorbed when given orally and act primarily in the distal convoluted tubule. Potassium-sparing diuretics (D) can be absorbed orally and exert their effects in the collecting duct of the nephron.