Hypervitaminosis is any of various abnormal conditions in which the physiological effect of a vitamin is produced to a pathological degree by excessive intake of the vitamin. This consideration is:

Correct Answer: A

Rationale: Step 1: Define hypervitaminosis as excessive intake of a vitamin leading to pathological effects. Step 2: Given definition matches the statement, making it True. Step 3: Other choices do not align with the definition; 'False' is opposite, 'All' and 'None' are generalizations not specific to the context. In summary, choice A is correct as it accurately reflects the definition of hypervitaminosis, while the other choices are incorrect due to being unrelated or too general.

Correct Answer: B

Rationale: The correct answer is B, Nicotinic acid (niacin). Niacin commonly causes flushing as a side effect due to prostaglandin release. Taking it after meals can slow down absorption and reduce flushing. Pretreatment with aspirin also helps by inhibiting prostaglandin synthesis. Lovastatin (A), Gemfibrozil (C), and Probucol (D) do not cause flushing as a side effect, so the strategies of taking after meals or pretreatment with aspirin would not be effective for reducing flushing caused by these drugs.

Correct Answer: A

Rationale: Rationale for correct answer (A): Alendronate is a bisphosphonate used to treat osteoporosis and Paget's disease by inhibiting bone resorption. It is not indicated for hypoparathyroidism, which involves low levels of calcium due to parathyroid hormone deficiency. Alendronate does not address the underlying cause of hypoparathyroidism. Summary of incorrect choices: B: Alendronate is used for glucocorticoid-induced osteoporosis. C: Alendronate is indicated for Paget's disease. D: Alendronate is effective for syndromes of ectopic calcification.

Correct Answer: B

Rationale: The correct answer is B: Furosemide (Lasix). Furosemide is a loop diuretic that inhibits sodium and chloride transport in the cortical thick ascending limb. This leads to increased excretion of these ions and water. Acetazolamide (A) inhibits carbonic anhydrase in the proximal tubule, Hydrochlorothiazide (C) acts on the distal convoluted tubule, and Amiloride (D) inhibits sodium reabsorption in the collecting duct. Therefore, only Furosemide affects sodium and chloride transport in the cortical thick ascending limb.

Correct Answer: C

Rationale: The correct answer is C: Lincomycin. Lincomycin is not a macrolide antibiotic, unlike the other options. Macrolide antibiotics have a macrocyclic lactone ring structure, which is absent in Lincomycin. Erythromycin, Clarithromycin, and Roxythromycin are macrolides with a similar structure and mechanism of action as they inhibit bacterial protein synthesis by binding to the 50S ribosomal subunit. Therefore, Lincomycin is the correct answer as it does not belong to the macrolide class of antibiotics.