ATI RN
Basic pharmacology principles Questions
Question 1 of 5
The excretion of a weakly acidic drug generally is more rapid in alkaline urine than in acidic urine. This process occurs because
Correct Answer: A
Rationale: A weak acid is excreted faster in alkaline urine because it exists primarily in its ionized form (A), less reabsorbed by renal tubules (e.g., aspirin at pH 8 > pKa 3.5), per Henderson-Hasselbalch. Option B is false; ionized is hydrophilic, not lipophilic. Option C is incorrect; pH effect is drug-specific. No option D or original E. This ion trapping accelerates clearance (e.g., in overdose), a key pharmacokinetic strategy, manipulating urine pH for therapeutic benefit.
Question 2 of 5
A hospitalized patient with systemic infection is receiving intravenous antibiotics. He also has hepatic and renal insufficiency. After receiving medications for 5 days, he is found by nursing staff to be jaundiced. Drug toxicology profile is obtained and indicated drug levels of 10 times the acceptable value. Which of the following drug administration schemes is most likely to explain this situation?
Correct Answer: A
Rationale: Continuous IV infusion (A) most likely explains the toxic drug levels (10× normal) and jaundice in this patient with hepatic and renal insufficiency. Constant delivery (e.g., vancomycin) overwhelms impaired clearance, causing accumulation over 5 days. Weekly (B) or twice-weekly (original E) injections allow recovery periods, less likely to build up. Daily (C) or twice-daily (D) bolus dosing risks peaks but less sustained excess than infusion. In hepatic/renal failure, reduced metabolism/excretion (e.g., bilirubin rise causing jaundice) amplifies toxicity, highlighting infusion's risk in such patients, requiring dose adjustment.
Question 3 of 5
A medical student is doing a summer research project studying five antibiotics to determine potency using the EC50. Antibiotics are placed in plated culture wells with 100,000 CFU of Escherichia coli. The EC50 results for the five antibiotics are shown in the following choices. Based on the results, the most potent antibiotic is
Correct Answer: B
Rationale: Antibiotic B (EC50 = 2) (B) is the most potent, as potency is inversely related to EC50:the lowest dose achieving 50\% effect (e.g., E. coli kill). Options A (100), C (80), and D (20) require higher doses; E (50, original) is intermediate. B's low EC50 indicates greater receptor affinity or efficacy per unit dose, critical in antibiotic selection, where potency guides efficacy against pathogens, though clinical use also weighs spectrum and resistance, making B superior in this lab context.
Question 4 of 5
A 15-year-old boy who has diabetes and is insulin dependent is brought to the emergency department after collapsing at a baseball game. His blood sugar is $463 \mathrm{mg} / \mathrm{dL}$ by finger stick. Which of the following routes of administration would be most efficacious for medications to bring the blood sugar down?
Correct Answer: B
Rationale: Intravenous (B) is most efficacious for insulin in this hyperglycemic crisis (463 mg/dL), delivering it directly to the bloodstream for rapid glucose uptake (within minutes), critical in diabetic ketoacidosis. Intramuscular (A) and subcutaneous (D) are slower (15-30 min onset). Oral (C) isn't viable for insulin (degraded by GI). Sublingual (original E) is impractical. IV's immediacy, bypassing absorption delays, ensures fast correction, vital in emergencies to prevent organ damage, a cornerstone of acute diabetes management.
Question 5 of 5
A 19-year-old female has a history of absence seizures. She currently takes ethosuximide to control her symptoms. The process of eliminating this drug involves multiple steps of metabolism followed by excretion. Many organs take part in both metabolism as well as excretion of drugs. Which of the following describes a step of metabolism?
Correct Answer: A
Rationale: Acetaminophen glucuronidation by enterocytes (A) is a metabolic step, a phase II reaction conjugating the drug for excretion, occurring in gut and liver. Digoxin transport (B) and pancuronium filtration (D) are excretion, not metabolism. Ethanol exhalation (C) is elimination via lungs, not transformation. Ethosuximide's hepatic metabolism (e.g., hydroxylation) parallels this, with enterocyte glucuronidation enhancing polarity, critical for clearance, distinguishing metabolism from mere transport in pharmacokinetics.