ATI RN
Ch 30 principles of pharmacology Questions
Question 1 of 5
Which tissue has the greatest capacity to bio-transform drugs?
Correct Answer: C
Rationale: The liver (C) has the greatest capacity to bio-transform drugs, via enzymes like CYP450 (e.g., oxidizing codeine to morphine), handling most metabolism due to its size and enzyme abundance. Brain (A) and kidney (B) have limited roles. Lung (D) metabolizes some (e.g., nicotine), less than liver. Skin (original E) is minimal. The liver's first-pass effect and phase I/II reactions (e.g., glucuronidation) detoxify and excrete drugs, central to pharmacokinetics, impacting bioavailability and clearance.
Question 2 of 5
Which of the following organisms can use only molecular oxygen as the final acceptor?
Correct Answer: C
Rationale: Obligate aerobes (C) use only molecular oxygen as the final electron acceptor in respiration (e.g., Mycobacterium tuberculosis), requiring Oâ‚‚ for survival. Obligate (A) and strict anaerobes (D) die with oxygen, using alternatives (e.g., nitrate). Facultative anaerobes (B) adapt to both. No original E. This oxygen dependence affects pathogenicity and drug targeting (e.g., TB's aerobic metabolism), contrasting with anaerobes like Clostridium, key in microbiology and antimicrobial therapy.
Question 3 of 5
Which of the following acids has the highest degree of ionization in an aqueous solution?
Correct Answer: A
Rationale: Aspirin (pKa 3.5) (A) has the highest ionization in aqueous solution (pH ~7), per Henderson-Hasselbalch: pH = pKa + log([Aâ»]/[HA]). Lower pKa means more ionization at neutral pH (aspirin ~99% ionized vs. ibuprofen ~95%). Indomethacin (B, 4.5), warfarin (C, 5.1), and ibuprofen (D) ionize less. Phenobarbital (original E, 7.4) is minimal. Aspirin's ionization enhances solubility and excretion, impacting its pharmacokinetics (e.g., renal clearance), a key factor in NSAID therapy.
Question 4 of 5
Which of the following drugs is considered to be the agent of choice for anaphylactic reactions?
Correct Answer: C
Rationale: Epinephrine (C) is the agent of choice for anaphylactic reactions, an α/β-agonist reversing bronchoconstriction, hypotension, and histamine effects (e.g., IM in anaphylaxis), acting within minutes. Clonidine (A) lowers blood pressure. Isoproterenol (B) is β-specific, less effective. Phenylephrine (D) is α-only, inadequate. Terbutaline (original E) is β₂-specific. Epinephrine's broad action, via cAMP and vasoconstriction, halts Type I hypersensitivity, critical in emergency pharmacology, with rapid onset and short duration.
Question 5 of 5
A 27-year-old female with vulvovaginal candidiasis is given a one-time $100 \mathrm{mg}$ dose of oral fluconazole. She has no other pertinent medical problems and takes no prescription medications. Administration of the medication results in a peak plasma concentration of $20 \mu \mathrm{g} / \mathrm{mL}$. What is the apparent volume of drug distribution?
Correct Answer: D
Rationale: The apparent volume of distribution (V_d) is 5 L (D). V_d = Dose / Plasma Concentration = $100 \, \text{mg} / 20 \, \mu\text{g/mL}$. Convert units: $100 \, \text{mg} = 100,000 \, \mu\text{g}$, so V_d = $100,000 \, \mu\text{g} / 20 \, \mu\text{g/mL} = 5000 \, \text{mL} = 5 \, \text{L}$. Options A (0.5 L), B (1 L), and C (3 L) underestimate; E (50 L, original) overestimates fluconazole's typical V_d (~0.7 L/kg, ~50 L for 70 kg), but D fits the given data. This moderate V_d reflects fluconazole's distribution into tissues beyond plasma, key for treating systemic candidiasis, with calculations aligning with pharmacokinetic principles for single-dose scenarios.