Indication for pamidronate administration is:

Correct Answer: D

Rationale: Step-by-step rationale for the correct answer (D): 1. Pamidronate is a bisphosphonate used to treat conditions involving excessive bone breakdown. 2. Hypercalcemia is a condition characterized by elevated calcium levels in the blood. 3. Pamidronate works by inhibiting bone resorption, which helps lower blood calcium levels in hypercalcemia. 4. Therefore, the indication for pamidronate administration is hypercalcemia. Summary of other choices: A: Failure of vitamin D formation in skin - Not related to pamidronate use. B: Hypoparathyroidism - Pamidronate is not indicated for hypoparathyroidism. C: Elevated skeletal turnover - While pamidronate is used for conditions involving high skeletal turnover, hypercalcemia is the primary indication for its administration.

Correct Answer: A

Rationale: The correct answer is A: Penicillin G. This is because Penicillin G has a shorter duration of action compared to the other choices. B, C, and D are all forms of long-acting penicillin preparations designed for sustained release over an extended period. Penicillin G, on the other hand, is a short-acting formulation that requires more frequent dosing due to its rapid elimination from the body. Therefore, Penicillin G does not demonstrate a prolonged effect like the other options.

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.