ATI RN
Basic pharmacology principles Questions
Question 1 of 5
CD4+T cells specifically recognize antigens in which form?
Correct Answer: C
Rationale: CD4+ T cells recognize antigens bound to MHC class II molecules on antigen-presenting cells (APCs) (C), like macrophages, triggering helper T-cell responses (e.g., cytokine release). MHC class I (A) is for CD8+ cells. Free antigens (B) don't activate T cells directly. No option D or original E. This MHC II restriction drives adaptive immunity, critical in vaccine design and immunosuppressive drugs (e.g., cyclosporine), shaping immune pharmacology.
Question 2 of 5
A 28-year-old man with seborrheic dermatitis is prescribed a topical corticosteroid crème by his dermatologist in hopes of alleviating the chronic rash and erythema on the cheeks. Which of the following steps is most critical to achieve a therapeutic drug concentration in plasma?
Correct Answer: A
Rationale: Absorption (A) is most critical to achieve a therapeutic plasma concentration for a topical corticosteroid. Applied to the skin, the drug must penetrate the stratum corneum to reach dermal blood vessels for systemic uptake (e.g., hydrocortisone for inflammation). Distribution (B) occurs post-absorption, spreading drug to tissues. Elimination (C) removes it, reducing levels. Glycosylation (D) and metabolism (original E) are irrelevant to initial plasma entry. Poor absorption (e.g., due to thick skin or low lipid solubility) limits systemic levels, critical for efficacy in seborrheic dermatitis if systemic effects are needed, though topical drugs primarily act locally, with plasma levels as a secondary outcome.
Question 3 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 4 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 5 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.