Which best describes the action of ACE inhibitors on the failing heart?

Correct Answer: D

Rationale: The correct answer is D: ACE inhibitors reduced preload. ACE inhibitors work by inhibiting the conversion of angiotensin I to angiotensin II, which leads to vasodilation and reduced preload on the heart. This results in decreased workload for the failing heart, improving its function. Explanation for why other choices are incorrect: A: ACE inhibitors do not increase aldosterone. In fact, they decrease aldosterone levels by inhibiting angiotensin II, which stimulates aldosterone release. B: ACE inhibitors do not increase vascular resistance. They actually reduce vascular resistance by blocking the vasoconstrictive effects of angiotensin II. C: ACE inhibitors do not decrease cardiac output. They may initially cause a slight decrease due to reduced preload, but overall they improve cardiac output by reducing the workload on the heart.

Correct Answer: C

Rationale: The correct answer is C: The median effective dose. ED50 refers to the dose of a drug that is required to produce a therapeutic effect in 50% of the population or experimental animals. This is a measure of the potency of a drug. The other choices are incorrect because: A: Half-life of the drug does not specifically refer to ED50. B: Half of the drug dose should be prescribed is not related to ED50, which is about effectiveness, not dosing. D: Half of the drug is eliminated is not the definition of ED50, as it pertains to the dose-response relationship, not elimination.

Correct Answer: D

Rationale: The correct answer is D: Acyclovir (Zovirax). The patient's symptoms of small, vascular lesions on the genitals lasting 10-20 days are indicative of a viral infection, likely herpes simplex virus. Acyclovir is an antiviral medication commonly used to treat herpes infections. It works by inhibiting the replication of the virus, reducing the duration and severity of symptoms. Test of cure (A) is not appropriate in this case as the diagnosis is already evident. Three injections of penicillin (B) are used for bacterial infections, not viral. One-time dose of azithromycin (C) is used for bacterial infections like chlamydia or gonorrhea, not viral lesions.

Correct Answer: C

Rationale: The correct answer is C: Thiazide or calcium channel blocker primary. This choice is correct because African Americans tend to respond better to thiazide diuretics and calcium channel blockers in managing hypertension. Thiazide diuretics are recommended as first-line treatment in this population due to their effectiveness and lower risk of adverse effects. Calcium channel blockers are also preferred as they have shown good efficacy and tolerability. Choice A (Clonidine) is incorrect as it is not recommended as a primary treatment option for hypertension. Choice B (Betablockers) is also incorrect as they are not the preferred initial treatment in African American patients due to lower efficacy compared to other drug classes. Choice D (ACE-1 inhibitors) is incorrect as they are not recommended as first-line treatment in this population, as they may be less effective in African Americans compared to other drug classes.

Correct Answer: C

Rationale: The correct answer is C, Treponema pallidum. This bacterium causes syphilis, a common sexually transmitted infection. Treponema pallidum is known for its transmission through sexual contact and can lead to serious health complications if left untreated. The other choices (A, B, D) are not typically associated with sexually transmitted infections and do not match the characteristics of a common STI like syphilis. Therefore, C is the correct answer based on its known transmission route and association with sexually transmitted bacterial infections.