ATI RN
Basic pharmacology principles Questions
Question 1 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 2 of 5
A 21-year-old man presents to his primary care physician complaining of a single, painless ulcer on his penis, which he first noticed a few days ago. He admits to multiple sexual partners. You want to treat him for syphilis with penicillin G, but his history includes an itchy rash following amoxicillin treatment as a child. What must first occur in the body for a penicillin to become allergenic?
Correct Answer: B
Rationale: Penicillin becomes allergenic by binding to a larger molecule (e.g., proteins) (B), forming a hapten-carrier complex the immune system recognizes as foreign, triggering IgE-mediated Type I hypersensitivity (e.g., rash). First-pass metabolism (A) isn't required. Simple exposure (C) needs sensitization first. Option D is false; penicillin's allergenicity is IgE-driven. This conjugation, critical in syphilis treatment (penicillin G), necessitates allergy screening, as prior amoxicillin reaction suggests risk, guiding alternative therapy (e.g., doxycycline).
Question 3 of 5
The following drugs exert their effects by binding to receptors and mimicking the effects of the endogenous ligand (i.e. are agonists):
Correct Answer: B
Rationale: Salbutamol (B) is an agonist, binding $\beta_2$-adrenergic receptors to mimic adrenaline, causing bronchodilation in asthma. Tamoxifen (A) is an estrogen receptor antagonist/partial agonist, not fully mimicking estrogen. Morphine (C) is an opioid agonist, mimicking endorphins for analgesia, also correct but B is selected. Cetirizine (D) is an Hâ‚ antihistamine antagonist, blocking histamine. Lisinopril (original E) inhibits ACE, not a receptor agonist. Agonists like salbutamol activate receptors to produce effects akin to endogenous ligands, critical in pharmacodynamics for therapeutic outcomes, distinguishing them from antagonists or enzyme inhibitors.
Question 4 of 5
For a drug that obeys first-order (linear) kinetics and fits a one-compartment model for elimination:
Correct Answer: A
Rationale: For first-order kinetics (A), elimination rate is proportional to plasma concentration (rate = k × Cp), as with most drugs (e.g., ibuprofen). Option B is true (exponential decline). Option C is false; half-life is constant. Option D is incorrect; GFR affects renally cleared drugs. Option E (original) about excretion composition is true but less central. This proportionality ensures predictable clearance (e.g., tâ‚/â‚‚ = 0.693/k), critical in dosing regimens, distinguishing first-order from zero-order saturation.
Question 5 of 5
The following are examples of prodrugs:
Correct Answer: A
Rationale: Levodopa (A) is a prodrug, converted to dopamine by DOPA decarboxylase in the brain for Parkinson's. Azathioprine (B) becomes 6-mercaptopurine, also correct but A is chosen. Penciclovir (C) is activated to penciclovir triphosphate. Sulfasalazine (D) splits into 5-ASA. Enalapril (original E) forms enalaprilat. Prodrugs like levodopa enhance delivery (e.g., BBB crossing), critical in pharmacokinetics, improving efficacy over active forms.