ATI RN
Ch 30 principles of pharmacology Questions
Question 1 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 2 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 3 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 4 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.
Question 5 of 5
A 47-year-old HIV positive male with hepatic insufficiency and renal insufficiency presents to his primary care physician complaining of dysuria. Urine culture reveals greater than 100,000 CFU/mL of Escherichia coli pan-sensitive to all antibiotics. Which of the following would be the most appropriate treatment for this patient?
Correct Answer: C
Rationale: Gentamicin (C) is most appropriate for this patient's E. coli UTI, given its renal excretion (less reliant on liver) and efficacy against Gram-negative bacteria, despite renal insufficiency requiring dose adjustment. Chloramphenicol (A) and erythromycin (B) are hepatically metabolized, risky with liver failure. Penicillin (D) is less effective against E. coli. Rifampin (original E) targets mycobacteria. Gentamicin's bactericidal action, monitored via levels, suits this immunocompromised patient, balancing efficacy and organ dysfunction, critical in HIV-related infections.