WGU D116 Advanced Pharmacology OA
ACTUAL EXAM 2026/2027 | Verified
Q&A with Detailed Answers | Pass
Guaranteed - A+ Graded
Unit 1: Pharmacokinetics & Pharmacodynamics (12 Questions)
Q1: A patient has been taking a drug with a half-life of 12 hours at a constant dose. Approximately how
long will it take to reach steady-state plasma concentration?
A. 24 hours
B. 36 hours
C. 48 hours
D. 60 hours [CORRECT]
Correct Answer: D
Rationale: Steady state is achieved after approximately 4–5 half-lives of continuous dosing. With a 12-
hour half-life, 5 half-lives equal 60 hours. This principle applies regardless of the specific drug or dose
administered.
Q2: A patient with severe hepatic cirrhosis is prescribed a highly protein-bound medication (90% bound
to albumin). The nurse understands that this patient is at increased risk for which effect?
A. Decreased drug absorption in the GI tract
B. Faster renal excretion of the drug
C. Increased free (unbound) drug concentration and enhanced toxicity [CORRECT]
D. Reduced drug distribution to peripheral tissues
Correct Answer: C
Rationale: Liver disease reduces albumin synthesis, decreasing available protein-binding sites. Highly
protein-bound drugs have fewer binding sites available, leading to higher free (active) drug levels. This
increases both therapeutic effects and toxicity risk.
,Q3: A nurse is reviewing a medication order for a drug that is a CYP3A4 substrate. The patient is also
taking ketoconazole, a known CYP3A4 inhibitor. What is the nurse's primary concern?
A. The drug will be metabolized more rapidly, requiring a dose increase
B. The drug's plasma concentration will increase, increasing toxicity risk [CORRECT]
C. The drug will have decreased bioavailability due to reduced absorption
D. The patient will develop an allergic cross-reaction between the two drugs
Correct Answer: B
Rationale: CYP3A4 inhibitors such as ketoconazole, grapefruit juice, and clarithromycin decrease the
metabolism of CYP3A4 substrates. This results in elevated plasma drug concentrations, prolonged half-
life, and increased risk of adverse effects and toxicity.
Q4: A patient asks why they must take their phenytoin at the same time every day. The nurse explains
that maintaining consistent plasma levels prevents which phenomenon?
A. First-pass effect
B. Tachyphylaxis
C. Seizure breakthrough due to subtherapeutic trough levels [CORRECT]
D. Drug-induced hepatotoxicity
Correct Answer: C
Rationale: Phenytoin has a narrow therapeutic index and zero-order kinetics at higher concentrations.
Inconsistent dosing leads to fluctuating peak and trough levels, increasing seizure risk at troughs and
toxicity at peaks.
Q5: A 78-year-old patient has a creatinine clearance of 35 mL/min. The prescriber orders a renally
excreted antibiotic. What adjustment is most appropriate?
A. Increase the dose and lengthen the dosing interval
B. Reduce the dose or extend the dosing interval to prevent drug accumulation [CORRECT]
C. Switch to an intravenous route to bypass renal excretion
D. No adjustment is needed for antibiotics in elderly patients
Correct Answer: B
,Rationale: Renal function declines with age, reducing drug clearance. For renally eliminated drugs, dose
reduction or interval extension prevents accumulation, toxicity, and adverse effects. The Cockcroft-Gault
equation guides dosing adjustments.
Q6: A patient is prescribed a drug with high first-pass hepatic metabolism. Which route of
administration would bypass this effect and result in higher bioavailability?
A. Oral
B. Subcutaneous
C. Intravenous [CORRECT]
D. Transdermal
Correct Answer: C
Rationale: Intravenous administration delivers 100% bioavailability by directly entering systemic
circulation, completely bypassing first-pass hepatic metabolism. Oral drugs with high first-pass
extraction (e.g., nitroglycerin, propranolol) have significantly reduced bioavailability.
Q7: A nurse is monitoring a patient receiving a loading dose of digoxin. The nurse understands that the
purpose of a loading dose is to achieve what pharmacokinetic goal?
A. Reduce the drug's volume of distribution
B. Accelerate the elimination of the drug
C. Achieve therapeutic plasma concentration more rapidly [CORRECT]
D. Prevent first-pass metabolism
Correct Answer: C
Rationale: A loading dose is a larger initial dose given to rapidly achieve therapeutic plasma
concentrations. Without a loading dose, reaching steady state would require 4–5 half-lives at
maintenance dosing, which may be too slow for critically ill patients.
Q8: A patient is taking warfarin and begins taking phenytoin, a CYP2C9 inducer. What effect should the
nurse anticipate?
A. The INR will increase, increasing bleeding risk
B. The INR will decrease, increasing clotting risk [CORRECT]
C. The warfarin dose should be increased immediately
D. No interaction occurs because the drugs use different metabolic pathways
, Correct Answer: B
Rationale: Phenytoin is a potent CYP450 enzyme inducer, accelerating warfarin metabolism. This
reduces warfarin plasma concentration, decreases INR, and increases thrombosis risk. INR monitoring
and warfarin dose adjustment are required.
Q9: A nurse is teaching a patient about a new prescription. The patient asks, "What does 'volume of
distribution' mean?" Which response is most accurate?
A. The amount of drug eliminated by the kidneys per hour
B. The theoretical fluid volume needed to contain the total drug at the same concentration as plasma
[CORRECT]
C. The speed at which the drug reaches peak plasma concentration
D. The percentage of drug absorbed from the GI tract
Correct Answer: B
Rationale: Volume of distribution (Vd) is a theoretical volume representing the fluid compartment size
needed to contain the total amount of drug at the same concentration as in plasma. Lipophilic drugs
have large Vd; hydrophilic drugs have small Vd.
Q10: A patient receiving a continuous IV infusion of a drug with a half-life of 6 hours has developed
toxicity. The prescriber stops the infusion. Approximately how long until 75% of the drug is eliminated?
A. 6 hours
B. 12 hours [CORRECT]
C. 18 hours
D. 24 hours
Correct Answer: B
Rationale: Drug elimination follows first-order kinetics: approximately 50% is eliminated per half-life.
After one half-life (6 hours), 50% remains; after two half-lives (12 hours), 25% remains (75% eliminated).
Q11: A nurse is caring for a patient with renal failure who requires an opioid for pain management.
Which opioid is the safest choice?
A. Morphine
B. Meperidine
C. Fentanyl [CORRECT]
ACTUAL EXAM 2026/2027 | Verified
Q&A with Detailed Answers | Pass
Guaranteed - A+ Graded
Unit 1: Pharmacokinetics & Pharmacodynamics (12 Questions)
Q1: A patient has been taking a drug with a half-life of 12 hours at a constant dose. Approximately how
long will it take to reach steady-state plasma concentration?
A. 24 hours
B. 36 hours
C. 48 hours
D. 60 hours [CORRECT]
Correct Answer: D
Rationale: Steady state is achieved after approximately 4–5 half-lives of continuous dosing. With a 12-
hour half-life, 5 half-lives equal 60 hours. This principle applies regardless of the specific drug or dose
administered.
Q2: A patient with severe hepatic cirrhosis is prescribed a highly protein-bound medication (90% bound
to albumin). The nurse understands that this patient is at increased risk for which effect?
A. Decreased drug absorption in the GI tract
B. Faster renal excretion of the drug
C. Increased free (unbound) drug concentration and enhanced toxicity [CORRECT]
D. Reduced drug distribution to peripheral tissues
Correct Answer: C
Rationale: Liver disease reduces albumin synthesis, decreasing available protein-binding sites. Highly
protein-bound drugs have fewer binding sites available, leading to higher free (active) drug levels. This
increases both therapeutic effects and toxicity risk.
,Q3: A nurse is reviewing a medication order for a drug that is a CYP3A4 substrate. The patient is also
taking ketoconazole, a known CYP3A4 inhibitor. What is the nurse's primary concern?
A. The drug will be metabolized more rapidly, requiring a dose increase
B. The drug's plasma concentration will increase, increasing toxicity risk [CORRECT]
C. The drug will have decreased bioavailability due to reduced absorption
D. The patient will develop an allergic cross-reaction between the two drugs
Correct Answer: B
Rationale: CYP3A4 inhibitors such as ketoconazole, grapefruit juice, and clarithromycin decrease the
metabolism of CYP3A4 substrates. This results in elevated plasma drug concentrations, prolonged half-
life, and increased risk of adverse effects and toxicity.
Q4: A patient asks why they must take their phenytoin at the same time every day. The nurse explains
that maintaining consistent plasma levels prevents which phenomenon?
A. First-pass effect
B. Tachyphylaxis
C. Seizure breakthrough due to subtherapeutic trough levels [CORRECT]
D. Drug-induced hepatotoxicity
Correct Answer: C
Rationale: Phenytoin has a narrow therapeutic index and zero-order kinetics at higher concentrations.
Inconsistent dosing leads to fluctuating peak and trough levels, increasing seizure risk at troughs and
toxicity at peaks.
Q5: A 78-year-old patient has a creatinine clearance of 35 mL/min. The prescriber orders a renally
excreted antibiotic. What adjustment is most appropriate?
A. Increase the dose and lengthen the dosing interval
B. Reduce the dose or extend the dosing interval to prevent drug accumulation [CORRECT]
C. Switch to an intravenous route to bypass renal excretion
D. No adjustment is needed for antibiotics in elderly patients
Correct Answer: B
,Rationale: Renal function declines with age, reducing drug clearance. For renally eliminated drugs, dose
reduction or interval extension prevents accumulation, toxicity, and adverse effects. The Cockcroft-Gault
equation guides dosing adjustments.
Q6: A patient is prescribed a drug with high first-pass hepatic metabolism. Which route of
administration would bypass this effect and result in higher bioavailability?
A. Oral
B. Subcutaneous
C. Intravenous [CORRECT]
D. Transdermal
Correct Answer: C
Rationale: Intravenous administration delivers 100% bioavailability by directly entering systemic
circulation, completely bypassing first-pass hepatic metabolism. Oral drugs with high first-pass
extraction (e.g., nitroglycerin, propranolol) have significantly reduced bioavailability.
Q7: A nurse is monitoring a patient receiving a loading dose of digoxin. The nurse understands that the
purpose of a loading dose is to achieve what pharmacokinetic goal?
A. Reduce the drug's volume of distribution
B. Accelerate the elimination of the drug
C. Achieve therapeutic plasma concentration more rapidly [CORRECT]
D. Prevent first-pass metabolism
Correct Answer: C
Rationale: A loading dose is a larger initial dose given to rapidly achieve therapeutic plasma
concentrations. Without a loading dose, reaching steady state would require 4–5 half-lives at
maintenance dosing, which may be too slow for critically ill patients.
Q8: A patient is taking warfarin and begins taking phenytoin, a CYP2C9 inducer. What effect should the
nurse anticipate?
A. The INR will increase, increasing bleeding risk
B. The INR will decrease, increasing clotting risk [CORRECT]
C. The warfarin dose should be increased immediately
D. No interaction occurs because the drugs use different metabolic pathways
, Correct Answer: B
Rationale: Phenytoin is a potent CYP450 enzyme inducer, accelerating warfarin metabolism. This
reduces warfarin plasma concentration, decreases INR, and increases thrombosis risk. INR monitoring
and warfarin dose adjustment are required.
Q9: A nurse is teaching a patient about a new prescription. The patient asks, "What does 'volume of
distribution' mean?" Which response is most accurate?
A. The amount of drug eliminated by the kidneys per hour
B. The theoretical fluid volume needed to contain the total drug at the same concentration as plasma
[CORRECT]
C. The speed at which the drug reaches peak plasma concentration
D. The percentage of drug absorbed from the GI tract
Correct Answer: B
Rationale: Volume of distribution (Vd) is a theoretical volume representing the fluid compartment size
needed to contain the total amount of drug at the same concentration as in plasma. Lipophilic drugs
have large Vd; hydrophilic drugs have small Vd.
Q10: A patient receiving a continuous IV infusion of a drug with a half-life of 6 hours has developed
toxicity. The prescriber stops the infusion. Approximately how long until 75% of the drug is eliminated?
A. 6 hours
B. 12 hours [CORRECT]
C. 18 hours
D. 24 hours
Correct Answer: B
Rationale: Drug elimination follows first-order kinetics: approximately 50% is eliminated per half-life.
After one half-life (6 hours), 50% remains; after two half-lives (12 hours), 25% remains (75% eliminated).
Q11: A nurse is caring for a patient with renal failure who requires an opioid for pain management.
Which opioid is the safest choice?
A. Morphine
B. Meperidine
C. Fentanyl [CORRECT]
