ATI RN
Ch 30 principles of pharmacology Questions
Question 1 of 5
Which of the following compounds are considered the building blocks of nucleic acids?
Correct Answer: A
Rationale: Nucleotides (A) are the building blocks of nucleic acids (DNA/RNA), comprising a sugar, phosphate, and base (e.g., ATP), polymerized via phosphodiester bonds. Nucleosides (B) lack phosphate. Monosaccharides (C) build carbohydrates. Purines (D) and amino acids (original E) are components, not full units. Nucleotides' role in genetic material and energy (e.g., GTP) underpins antiviral drugs (e.g., acyclovir), targeting replication, a critical biochemical and pharmacological concept.
Question 2 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 3 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 4 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.
Question 5 of 5
The P-glycoprotein is a multidrug transmembrane transporter protein that transports medications across cell membranes. Functions of this protein include
Correct Answer: B
Rationale: P-glycoprotein (P-gp) transports drugs into liver hepatocytes (B), effluxing substrates (e.g., digoxin) into bile for elimination, a key hepatic function. It pumps drugs out of cells (e.g., into intestinal lumen or bile), not into urine (A, renal role). It limits fetal entry (C is opposite), protecting the fetus. It effluxes drugs from enterocytes to lumen (D is reversed). Brain efflux (original E) restricts CNS entry. P-gp's hepatic role reduces bioavailability, critical in drug interactions (e.g., with rifampin), influencing pharmacokinetics in liver-centric metabolism.