All of the following antiviral drugs are antiretroviral agents, EXCEPT:

Correct Answer: A

Rationale: The correct answer is A: Acyclovir. Acyclovir is not an antiretroviral agent, as it is primarily used to treat herpes virus infections. Zidovudine, Zalcitabine, and Didanozine are all antiretroviral drugs used specifically to treat HIV infections. These drugs work by inhibiting the replication of the HIV virus. Acyclovir, on the other hand, works by inhibiting the replication of herpes viruses. Therefore, Acyclovir does not target HIV and is not classified as an antiretroviral agent.

Correct Answer: B

Rationale: The correct answer is B: Inhibition of epinephrine release from the adrenal medulla. Atenolol is a beta-blocker that primarily works by blocking beta-adrenergic receptors, leading to decreased release of epinephrine and norepinephrine. This results in reduced heart rate, cardiac output, and renin release, leading to decreased blood pressure. A: Dilation of large veins is not the primary mechanism of action of atenolol. It primarily affects the heart and vasculature by blocking beta-receptors. C: While atenolol does block beta receptors in the vascular wall, the primary mechanism of antihypertensive effect is through inhibition of epinephrine release. D: Atenolol does not directly affect sympathetic outflow from the vasomotor area. The main mechanism is through blocking beta-receptors and reducing catecholamine release.

Correct Answer: C

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

Correct Answer: D

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

Correct Answer: D

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