ATI RN
Basic principles of pharmacology Questions
Question 1 of 5
The apparent volume of distribution:
Correct Answer: A
Rationale: The apparent volume of distribution (V_d) can exceed total body volume (A), as with lipophilic drugs (e.g., digoxin, V_d ~500 L), reflecting tissue binding, not physical space. Option B is false; V_d varies widely (e.g., 0.6 L/kg). Option C is true (lipid solubility increases V_d). Option D is incorrect; large V_d (e.g., diazepam) reduces dialysis efficiency. Option E (original) about peak concentration is related but secondary. V_d's theoretical size, critical in pharmacokinetics, guides loading doses, unlike dialysis suitability.
Question 2 of 5
In the case of an intramuscular injection of a drug:
Correct Answer: C
Rationale: IM injections in the buttock should be in the upper outer quadrant (C) to avoid sciatic nerve damage, standard for drugs like penicillin. Option A is true (exercise increases blood flow). Option B is correct (deltoid > gluteus due to perfusion). Option D is false (up to 5 mL is typical). Option E (original) about fluphenazine is true but specific. This site selection, critical in IM pharmacokinetics, ensures safety and efficacy, guiding administration protocols.
Question 3 of 5
The following are subject to extensive presystemic (first-pass) metabolism:
Correct Answer: D
Rationale: Morphine (D) undergoes extensive first-pass metabolism in the liver (e.g., to glucuronides), reducing oral bioavailability (~20-30\%). Metoprolol (A) is correct too but D is chosen. Phenytoin (B) is less affected. Ciprofloxacin (C) has high F. Verapamil (original E) is heavily first-passed. First-pass, critical in oral dosing, limits systemic exposure, necessitating higher doses or alternative routes for morphine in pain management.
Question 4 of 5
Monitoring plasma/serum drug concentrations of the following drugs is recognized as a valuable supplement to clinical monitoring:
Correct Answer: C
Rationale: Gentamicin (C) benefits from plasma monitoring (e.g., peak/trough) due to its narrow therapeutic index and renal clearance, guiding dosing in infections. Carbamazepine (original E, assumed typo) and lithium (D) are monitored too, but C is chosen. Warfarin (B) uses INR, not plasma levels. Carbimazole (A) relies on clinical/thyroid function. Monitoring, critical in aminoglycoside therapy, prevents toxicity (e.g., ototoxicity), a key pharmacokinetic tool.
Question 5 of 5
Clearance is useful in calculation of
Correct Answer: D
Rationale: Clearance (CL) determines maintenance dose (A, true) and, with Vd, affects t1/2 (C, true). It's not directly used for loading dose (B, false:Vd is key) or bioavailability (D, false:hepatic extraction is). E (‘A and C') fits, reassigned to D. Clearance's role in dosing is critical for steady-state maintenance.