All of the following antiviral drugs are the analogs of nucleosides, EXCEPT:

Correct Answer: C

Rationale: The correct answer is C: Saquinavir. Saquinavir is a protease inhibitor, not a nucleoside analog. Nucleoside analogs (A, B, D) mimic nucleosides and interfere with viral replication by inhibiting DNA or RNA synthesis. Acyclovir (A) is used for herpes viruses, Zidovudine (B) for HIV, Didanosine (D) for HIV. Saquinavir (C) inhibits protease enzyme in HIV, preventing viral maturation.

Correct Answer: B

Rationale: The correct answer is B: Blockade of Na+ channels in the collecting duct. This action prevents Na+ reabsorption, leading to increased Na+ in the urine and decreased K+ secretion. This mechanism is seen in potassium-sparing diuretics like amiloride and triamterene. Choices A and C do not directly impact potassium sparing. Choice D is incorrect as aldosterone receptor blockade would lead to increased K+ excretion.

Correct Answer: D

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

Correct Answer: B

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

Correct Answer: C

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