The drug acts at the proximal tubule:

Correct Answer: D

Rationale: The correct answer is D: Carbonic anhydrase inhibitors. These drugs act at the proximal tubule by inhibiting the enzyme carbonic anhydrase, which leads to decreased reabsorption of bicarbonate and sodium. This results in increased urinary excretion of bicarbonate and sodium, leading to diuresis. Loop diuretics (A) act at the thick ascending limb of the loop of Henle, thiazide diuretics (B) act at the distal convoluted tubule, and potassium-sparing diuretics (C) act at the collecting duct. Therefore, choices A, B, and C are incorrect as they do not target the proximal tubule.

Correct Answer: A

Rationale: The correct answer is A: Decrease mycobacterium drug-resistance. Combined chemotherapy of tuberculosis involves using multiple drugs to target different stages of the bacteria's life cycle, reducing the chances of resistance developing. This approach is effective in preventing the bacteria from adapting and becoming resistant to any single drug. Explanation: 1. Using multiple drugs targets different mechanisms of action, making it harder for the bacteria to develop resistance. 2. Combination therapy can also prevent the growth of drug-resistant strains by attacking the bacteria from multiple angles. 3. By reducing the likelihood of resistance, combined chemotherapy increases the effectiveness of treatment and improves patient outcomes. Summary: B: Increase mycobacterium drug-resistance - This is incorrect as combined chemotherapy aims to decrease, not increase, drug resistance. C: Decrease the antimicrobial activity - This is incorrect as combined chemotherapy actually enhances the antimicrobial activity against the tuberculosis bacteria. D: Decrease the onset of antimycobacterial drugs biotransformation - This is

Correct Answer: D

Rationale: The correct answer is D: Acyclovir. Acyclovir is a nucleoside analogue that inhibits viral DNA synthesis by acting as a chain terminator when incorporated into the viral DNA. Interferon (A) boosts the immune response, Saquinavir (B) inhibits HIV protease, and Amantadine (C) blocks viral entry. Therefore, only Acyclovir directly targets viral DNA synthesis.

Correct Answer: D

Rationale: The correct answer is D (Drug S) because it is a loop diuretic, which acts on the ascending loop of Henle to inhibit sodium and chloride reabsorption, leading to a significant increase in diuresis. Loop diuretics are the most potent diuretics among the options provided. Drug P (Choice A) is a thiazide diuretic that acts on the distal convoluted tubule and is less potent than loop diuretics. Drug Q (Choice B) is a potassium-sparing diuretic that acts on the collecting ducts and is weaker in terms of diuretic effect compared to loop diuretics. Drug R (Choice C) is an aldosterone antagonist that acts on the distal tubules and collecting ducts, but it is less potent compared to loop diuretics in increasing diuresis.

Correct Answer: A

Rationale: The correct answer is A: Isosorbide mononitrate and nifedipine. Isosorbide mononitrate dilates coronary arteries, reducing myocardial oxygen demand. Nifedipine is a calcium channel blocker that helps reduce cardiac workload. Together, they can help manage symptoms of hypertrophic cardiomyopathy. Choice B (Nitroglycerin and captopril) is incorrect because captopril is an ACE inhibitor used for heart failure, not hypertrophic cardiomyopathy. Choice C (Nitroglycerin and verapamil) is incorrect because verapamil can worsen symptoms due to its negative inotropic effects. Choice D (Verapamil and metoprolol) is incorrect because metoprolol is a beta-blocker, which can worsen symptoms in hypertrophic cardiomyopathy by reducing heart rate and contractility.