An 80-year-old patient who has COPD takes TMP/SMX for acute exacerbations, which occur three or four times each year. To monitor this patient for adverse drug reactions, the primary care NP should order:

Correct Answer: D

Rationale: The correct answer is D because elderly patients on TMP/SMX risk bone marrow suppression, monitored via CBC. Choice A is incorrect (liver tests pre-treatment). Choice B is wrong (renal pre-treatment). Choice C is inaccurate (bilirubin not primary).

Correct Answer: S

Rationale: Choice A is correct because clinical judgment involves balancing efficacy, safety, and cost to ensure patients can afford and adhere to treatment, which is critical for successful outcomes. Choice B is incorrect as always choosing the newest medication ignores evidence-based practice; newer drugs may lack long-term data or be unnecessarily expensive. Choice C is wrong because distributing samples isn't a sustainable prescribing strategy and may not meet ongoing needs. Choice D is also incorrect since mandating generics could compromise efficacy if a brand-name drug is clinically necessary.

Correct Answer: C

Rationale: Choice C is correct because the onset of action is when a drug first shows a therapeutic effect on the concentration curve, marking the start of its clinical impact. Choice A is incorrect as ‘minimum adverse effect level' isn't a standard term; it confuses with toxicity thresholds. Choice B is wrong because peak of action is the maximum effect, not the first sign. Choice D is incorrect since therapeutic range is the concentration window for efficacy, not a specific time point.

Correct Answer: B

Rationale: Choice B is correct because the blood-brain barrier, with its tight junctions, slows entry of many drugs, especially water-soluble ones, protecting the brain. Choice A is incorrect as water-soluble, ionized drugs cross poorly due to barrier selectivity. Choice C is wrong because the fetal-placental barrier doesn't fully block drugs—many cross and affect the fetus. Choice D is incorrect since lipid-soluble drugs readily pass these barriers, posing risks in pregnancy.

Correct Answer: D

Rationale: Choice D is correct because frequent agonist use can cause the body to downregulate receptors, reducing sensitivity to overstimulation as a compensatory mechanism. Choice A is incorrect as upregulation occurs with antagonists, not agonists. Choice B is wrong because partial agonists compete, not result from frequent use. Choice C is incorrect since metabolism changes aren't the primary receptor response.