Antibiotics altering permeability of cell membranes are:

Correct Answer: B

Rationale: The correct answer is B: Polymyxins. Polymyxins are antibiotics that work by altering the permeability of the bacterial cell membrane, leading to leakage of cellular contents and ultimately bacterial cell death. This mechanism of action is specific to polymyxins, making it the correct choice. Incorrect Choices: A: Glycopeptides - Glycopeptides work by inhibiting cell wall synthesis, not by altering cell membrane permeability. C: Tetracyclines - Tetracyclines inhibit protein synthesis in bacteria, they do not target cell membrane permeability. D: Cephalosporins - Cephalosporins interfere with cell wall synthesis, they do not directly affect cell membrane permeability.

Correct Answer: D

Rationale: The correct answer is D: Ivermectin. Ivermectin is the drug of choice for strongyloidiasis due to its high efficacy and low toxicity. It works by paralyzing and killing the parasites. Niclosamide (A) is used for tapeworm infections, Praziquantel (B) for schistosomiasis, and Bithionol (C) for fascioliasis. Therefore, D is the correct choice for treating strongyloidiasis.

Correct Answer: C

Rationale: The correct answer is C: Demeclocycline. This drug is specifically used to treat the condition of syndrome of inappropriate antidiuretic hormone secretion (SIADH), which is common in elderly patients. Demeclocycline works by inhibiting the action of antidiuretic hormone, thus promoting water diuresis. Desmopressin (choice A) is used to treat diabetes insipidus, the opposite of SIADH. Hydrochlorothiazide (choice B) and Amiloride (choice D) are diuretics commonly used for different conditions like hypertension and edema but are not indicated for SIADH.

Correct Answer: C

Rationale: Rationale for Correct Answer C: Furosemide inhibits Na+/K+/2Cl- cotransporter in the loop of Henle, leading to decreased Na+ reabsorption. This results in increased delivery of Na+ to the distal tubule, stimulating H+ secretion and bicarbonate reabsorption, causing metabolic alkalosis. Mild inhibition of carbonic anhydrase by furosemide also contributes by reducing H+ secretion in the proximal tubule. Summary of Incorrect Choices: A: Increased reabsorption of uric acid is not directly related to furosemide-induced metabolic alkalosis. B: Increased delivery of Na+ to the distal tubule is a consequence of furosemide action but does not directly contribute to metabolic alkalosis. D: Decreased reabsorption of Ca2+ in the loop of Henle may lead to hypocalcemia but is not a direct cause of metabolic alkalosis in this case.

Correct Answer: C

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.