Nokea
Which of the following statements about the major distribution barriers (blood-brain or fetal-placental) is true?
- A. Water soluble and ionized drugs cross these barriers rapidly.
- B. The blood-brain barrier slows the entry of many drugs into and from brain cells.
- C. The fetal-placental barrier protects the fetus from drugs taken by the mother.
- D. Lipid-soluble drugs do not pass these barriers and are safe for pregnant women.
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.
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An agonist activates a receptor and stimulates a response. When given frequently over time, the body may:
- A. Upregulate the total number of receptors
- B. Block the receptor with a partial agonist
- C. Alter the drug's metabolism
- D. Downregulate the numbers of that specific receptor
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.
Over-the-counter drugs that should be avoided in patients with hypertension include:
- A. Acetaminophen
- B. Pseudoephedrine
- C. Ibuprofen
- D. All of the above
Correct Answer: B
Rationale: Choice B is correct because pseudoephedrine, a decongestant, raises blood pressure via vasoconstriction, risky in hypertension, per guidelines. Choice A is incorrect as acetaminophen doesn't affect BP. Choice C is wrong because ibuprofen's BP effect is milder and not absolute avoidance. Choice D is incorrect since only pseudoephedrine is key.
The primary care NP sees a 4-year-old child who has received four doses of PCV 7 in the first 15 months of life. The NP should administer:
- A. PCV 7.
- B. PCV 13.
- C. PPV 23.
- D. no PCV.
Correct Answer: B
Rationale: The correct answer is B because children under 5 with PCV 7 series should get one PCV 13 dose. Choice A is incorrect (PCV 7 outdated). Choice C is wrong (PPV 23 not for this age). Choice D is inaccurate (vaccine needed).
Genetic testing prior to prescribing which drug could prevent serious adverse drug reactions?
- A. Acetaminophen
- B. Codeine
- C. Albuterol
- D. All of the above
Correct Answer: B
Rationale: Choice B is correct because genetic testing for CYP2D6 variants can prevent ADRs with codeine; poor metabolizers get no pain relief, while ultrarapid metabolizers risk morphine toxicity. Choice A is incorrect as acetaminophen metabolism isn't strongly tied to genetic variants causing serious ADRs. Choice C is wrong because albuterol's inhaled use has minimal genetic metabolism risks. Choice D is incorrect since only codeine benefits significantly from pre-prescribing genetic testing.
Drugs that may increase risk of erectile dysfunction include:
- A. Testosterone
- B. Beta blockers
- C. Alpha blockers
- D. All of the above
Correct Answer: B
Rationale: Choice B is correct because beta blockers (e.g., propranolol) can cause erectile dysfunction by reducing blood flow, a known side effect. Choice A is incorrect as testosterone improves erectile function. Choice C is wrong because alpha blockers often treat ED causes. Choice D is incorrect since only beta blockers fit.