The drug competitively blocks chloride channels and prevents movement of sodium, potassium, and chloride into the renal tubular cells:

Correct Answer: A

Rationale: The correct answer is A: Furosemide (Lasix). Furosemide is a loop diuretic that competitively blocks chloride channels in the ascending loop of Henle, preventing the reabsorption of sodium, potassium, and chloride in the renal tubules. This mechanism leads to increased excretion of these ions and water, resulting in diuresis. Acetazolamide (B) inhibits carbonic anhydrase, Triamterene (C) blocks sodium channels, and Mannitol (D) is an osmotic diuretic. Therefore, these choices do not competitively block chloride channels like Furosemide does in the renal tubular cells.

Correct Answer: C

Rationale: Step-by-step rationale for choice C: 1. Sodium stibogluconate is a first-line treatment for leishmaniasis. 2. It is an antimonial compound effective against Leishmania parasites. 3. It is administered intravenously for visceral leishmaniasis. 4. Has been used for decades with proven efficacy. Summary of other choices: A: Pyrimethamine - used for malaria, not leishmaniasis. B: Albendazole - used for helminthic infections, not leishmaniasis. D: Tinidazole - used for protozoal infections like Giardiasis, not leishmaniasis.

Correct Answer: A

Rationale: The correct answer is A: Provide synergism resulting from the use of anticancer drugs with different mechanisms combination. Rational combination of anticancer drugs with different mechanisms can target multiple pathways in cancer cells, leading to enhanced efficacy and reduced chances of drug resistance. This synergy can result in improved treatment outcomes. Choices B, C, and D are incorrect: B: Providing synergism from using anticancer drugs with the same mechanisms combination would not enhance the effectiveness of treatment. C: Stimulating the immune system is a different approach to cancer treatment and is not related to rational drug combinations. D: Stimulation of cell proliferation would be counterproductive in cancer treatment as the goal is to inhibit cancer cell growth, not promote it.

Correct Answer: D

Rationale: The correct answer is D because loop diuretics act on the ascending loop of Henle to inhibit sodium and water reabsorption, promoting diuresis. This mechanism is independent of the glomerular filtration rate (GFR), making them effective even in low GFR situations common in heart failure. Explanation for other choices: A: Loop diuretics do not inhibit angiotensin II synthesis; this is the mechanism of ACE inhibitors. B: Loop diuretics do not increase venous return to the heart; this is the mechanism of drugs like nitrates. C: Loop diuretics do not inhibit renal prostaglandin biosynthesis; this is the mechanism of NSAIDs.

Correct Answer: C

Rationale: The correct answer is C: Furosemide. In bilateral adrenal hyperplasia, excess production of aldosterone occurs, leading to fluid retention and hypertension. Furosemide is a loop diuretic that helps reduce blood volume and lower blood pressure by promoting the excretion of sodium and water in the urine. This drug is commonly used to manage hypertension associated with adrenal gland disorders. Step-by-step rationale: 1. Identify the condition: bilateral adrenal hyperplasia. 2. Understand the pathophysiology: aldosterone excess leads to fluid retention and hypertension. 3. Choose the appropriate drug class: diuretics to reduce blood volume and lower blood pressure. 4. Select the specific drug: Furosemide, a loop diuretic, is effective in managing hypertension associated with adrenal gland disorders. Summary: A: Hydrochlorothiazide - Thiazide diuretic, not as effective in cases of aldosterone excess. B: Mannitol - Osmotic diure