Nutritional intake that may impact drug action includes:

Correct Answer: A

Rationale: Choice A is correct because protein intake affects albumin levels, altering drug binding and free drug availability, directly impacting action. Choice B is incorrect as iron intake influences absorption of some drugs (e.g., tetracyclines), not action broadly. Choice C is wrong because vitamin D affects bone health, not drug action directly. Choice D is incorrect since only protein has a widespread pharmacokinetic impact.

Correct Answer: B

Rationale: Choice B is correct because St John's wort induces P-glycoprotein and CYP3A4, reducing digoxin levels and efficacy, a significant interaction. Choice A is incorrect as ginkgo biloba doesn't notably affect digoxin. Choice C is wrong because valerian root has minimal impact on digoxin pharmacokinetics. Choice D is incorrect since only St John's wort interacts markedly.

Correct Answer: B

Rationale: Choice B is correct because a peak level above the minimum toxic concentration indicates the drug concentration exceeds the safe therapeutic range, likely causing adverse effects. Choice A is incorrect as therapeutic effects occur below toxicity, not above. Choice C is wrong because shortening doses doesn't address an already toxic level; dose reduction is needed. Choice D is incorrect since duration isn't the issue—peak concentration is.

Correct Answer: D

Rationale: Choice D is correct because liver metabolism can produce metabolites that are more active (e.g., prodrugs like codeine to morphine), less active, or inactive, depending on the drug, making all options possible. Choice A is incorrect as it's only one scenario, not the full range. Choice B is wrong because it excludes cases where metabolites are more active. Choice C is incorrect since not all metabolites are deactivated—some retain or gain activity.

Correct Answer: B

Rationale: Choice B is correct because diphenhydramine (per Beers Criteria) is contraindicated in the elderly due to anticholinergic effects risking delirium and urinary retention. Choice A is incorrect as acetaminophen is safe. Choice C is wrong because amoxicillin is not contraindicated. Choice D is incorrect since only diphenhydramine applies.

Correct Answer: C

Rationale: The correct answer is C because a higher concentration (500 mg/5 mL) and bid dosing simplifies administration, enhancing compliance. Choice A is incorrect (lower concentration, less convenient). Choice B is wrong (tid less convenient). Choice D is inaccurate (tid and lower dose inconvenient).

Correct Answer: D

Rationale: Choice D is correct because poor handwriting, sound-alike names (e.g., Celebrex vs. Celexa), and look-alike packaging all contribute to medication errors, per safety studies. Choice A is incorrect alone as it's one cause. Choice B is wrong by itself because sound-alikes are just one risk. Choice C is incorrect solo since packaging is only part of the problem.

Correct Answer: D

Rationale: Choice D is correct because enteric-coated tablets need ample fluid (e.g., 8 ounces) to ensure proper passage and dissolution in the intestines, not stomach, for optimal effect. Choice A is incorrect as avoiding other drugs isn't a general rule unless specified. Choice B is wrong because dissolving enteric-coated tablets destroys their protective coating. Choice C is incorrect since crushing negates the coating's purpose.

Correct Answer: C

Rationale: The correct answer is C because preterm infants (32-35 weeks) under 3 months at RSV season start need three Synagis doses. Choice A is incorrect (one dose insufficient). Choice B is wrong (prophylaxis indicated). Choice D is inaccurate (three doses, not until April).