A patient who takes warfarin (Coumadin) experiences excessive bleeding, even though serum drug levels are normal. The primary care NP should question this patient about the use of:

Correct Answer: D

Rationale: The correct answer is D because ginkgo biloba decreases blood viscosity, enhancing warfarin’s bleeding risk. Choices A, B, and C are incorrect as they don’t significantly affect bleeding with warfarin.

Correct Answer: B

Rationale: The correct answer is B because low albumin from malnutrition increases free warfarin levels, requiring the lowest dose initially. Choice A is incorrect as LFTs aren’t indicated here. Choice C is wrong since diet doesn’t directly address albumin binding. Choice D is inaccurate as food doesn’t enhance warfarin absorption significantly.

Correct Answer: A

Rationale: Choice A is correct because warfarin is metabolized by CYP2C9, and variants affect its dosing due to altered clearance rates, unlike the others. Choice B is incorrect as codeine uses CYP2D6, not CYP2C9, for activation. Choice C is wrong because acetaminophen is primarily glucuronidated, not CYP2C9-dependent. Choice D is incorrect since only warfarin fits this metabolic pathway.

Correct Answer: B

Rationale: Choice B is correct because START (Screening Tool to Alert to Right Treatment) identifies underused beneficial drugs (e.g., statins) in the elderly, per guidelines. Choice A is incorrect as that's STOPP's role. Choice C is wrong because it's not about levels. Choice D is incorrect since only B fits.

Correct Answer: D

Rationale: Choice D is correct because prescriptions are required for legend drugs (FDA-approved prescription drugs), most controlled drugs (DEA-regulated), and certain medical devices, covering all categories listed. Choice A is incorrect alone as it excludes controlled drugs and devices. Choice B is wrong by itself because it misses legend drugs and devices. Choice C is incorrect solo since it omits drugs entirely.

Correct Answer: A

Rationale: Choice A is correct because sublingual administration allows rapid absorption via the rich blood supply under the tongue, bypassing first-pass metabolism for quick onset. Choice B is incorrect as excretion rate isn't directly affected by this route. Choice C is wrong because minimal metabolism is a benefit, not the defining advantage. Choice D is incorrect since distribution isn't equal—it's systemic, not a primary advantage.

Correct Answer: A

Rationale: The correct answer is A because valproic acid depletes folic acid, necessitating supplements to reduce fetal risk. Choice B is incorrect (changing meds mid-pregnancy is risky). Choice C is wrong (vitamin K is for later gestation). Choice D is inaccurate (discontinuing not advised without specialist consult).

Correct Answer: B

Rationale: Choice B is correct because IV drugs bypass absorption, entering the bloodstream directly and beginning distribution immediately, ensuring rapid onset. Choice A is incorrect as lipid solubility matters for oral absorption, not IV, where absorption isn't a factor. Choice C is wrong because ionization affects absorption in other routes, not IV delivery. Choice D is incorrect since pinocytosis is a cellular uptake mechanism, not relevant to IV administration.

Correct Answer: C

Rationale: The correct answer is C because CRNAs in most states can order and administer controlled substances without full prescriptive authority, as they dispense directly. Choice A is incorrect since a DEA number isn’t required without prescriptive authority. Choice B is wrong as only five states grant full authority. Choice D is inaccurate as supervision isn’t always required.