The drug can be used to treat nephrogenic diabetes insipidus:

Correct Answer: A

Rationale: Step-by-step rationale for why choice A (Hydrochlorothiazide) is correct: 1. Hydrochlorothiazide is a thiazide diuretic that decreases urine volume by increasing water reabsorption. 2. In nephrogenic diabetes insipidus, the kidneys are unable to respond to antidiuretic hormone (ADH), causing excessive urine production. 3. Hydrochlorothiazide can help reduce urine output by enhancing water reabsorption, thus alleviating symptoms of nephrogenic diabetes insipidus. Summary of other choices: - Choice B (Amiloride) is a potassium-sparing diuretic that does not directly address the underlying mechanism of nephrogenic diabetes insipidus. - Choice C (Both of the above) is incorrect as only Hydrochlorothiazide is indicated for treating nephrogenic diabetes insipidus. - Choice D (Neither of the above) is incorrect as Hydrochlorothiazide is indeed

Correct Answer: C

Rationale: Step-by-step rationale for choice C: 1. Ethambutol is known to cause retrobulbar neuritis, a condition that affects the optic nerve leading to vision changes. 2. The specific symptom of red-green color blindness is commonly associated with ethambutol toxicity. 3. This effect is due to the drug's direct impact on the optic nerve. 4. Regular monitoring of visual acuity and color vision is recommended during ethambutol treatment. Summary of other choices: A. Cardiotoxicity: Ethambutol is not known to cause direct cardiotoxic effects. B. Immunetoxicity: Ethambutol primarily affects the optic nerve, not the immune system. D. Hepatotoxicity: Ethambutol is generally well-tolerated by the liver and does not commonly cause hepatotoxicity.

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.