NR565 Advanced Pharmacology Fundamentals | Week 4 Midterm Exam | Comprehensive
Exemplify-Style Practice Questions & Answer Guide
Question 1
A patient is prescribed a drug that is a weak base with a pKa of 8.4. In which part of the body
will this drug be most highly ionized?
A) Small intestine (pH 7.4)
B) Stomach (pH 1.5-3.5)
C) Blood (pH 7.35-7.45)
D) Urine (pH 5.0-8.0)
Correct Answer: B) Stomach (pH 1.5-3.5)
Rationale: Weak bases are more ionized in acidic environments (low pH). Ionized drugs are
poorly absorbed across lipid membranes. The stomach's low pH favors ionization of weak bases,
making them less likely to be absorbed. Weak acids are better absorbed in the stomach; weak
bases are better absorbed in the small intestine.
Question 2
Which pharmacokinetic process is most affected by first-pass metabolism?
A) Distribution
B) Metabolism
C) Oral absorption
D) Renal excretion
Correct Answer: C) Oral absorption
,Rationale: First-pass metabolism occurs in the liver and gut wall after oral administration,
reducing the amount of active drug reaching systemic circulation. Drugs with extensive first-pass
effect often require higher oral doses or alternative routes (IV, sublingual, transdermal) .
Question 3
A drug with a narrow therapeutic index (e.g., lithium, warfarin) requires:
A) Less frequent monitoring
B) More frequent monitoring of serum drug levels
C) Administration with food only
D) Use only in pediatric patients
Correct Answer: B) More frequent monitoring of serum drug levels
Rationale: Drugs with a narrow therapeutic index have a small margin between therapeutic and
toxic doses. Frequent monitoring of serum levels is required to ensure the dose remains within
the safe and effective window .
Question 4
What does bioavailability refer to?
A) The amount of drug that reaches systemic circulation unchanged
B) The rate at which drug is metabolized
C) The time it takes for drug to be eliminated
D) The volume of distribution
Correct Answer: A) The amount of drug that reaches systemic circulation unchanged
,Rationale: Bioavailability (F) is the fraction of the administered dose that reaches systemic
circulation unchanged. IV drugs have 100% bioavailability; oral drugs have variable
bioavailability due to incomplete absorption and first-pass metabolism .
Question 5
The time required for half of a drug concentration to be eliminated from the body is called:
A) Peak level
B) Bioavailability
C) Half-life
D) Potency
Correct Answer: C) Half-life
Rationale: Half-life determines dosing intervals and duration of action. It is the time required for
the drug concentration in the body to be reduced by 50% .
Question 6
What is the CYP450 (cytochrome P450) system?
A) Kidney enzyme system where medications are excreted
B) Liver enzyme system where medications are metabolized
C) GI tract system where medications are absorbed
D) Blood system where medications are distributed
Correct Answer: B) Liver enzyme system where medications are metabolized
Rationale: The CYP450 system is a liver enzyme system where medications are metabolized.
Enzymes can either be inducers or inhibitors and create drug-drug interactions .
, Question 7
Which statement about CYP450 inducers is correct?
A) They slow down metabolism of drugs
B) They speed up metabolism of drugs, causing drugs to have lesser effect
C) They have no effect on drug metabolism
D) They only affect IV medications
Correct Answer: B) They speed up metabolism of drugs, causing drugs to have lesser effect
Rationale: CYP450 inducers speed up metabolism of drugs, meaning the drug is cleared faster
and has a lesser effect. They elevate CYP450 enzyme activity .
Question 8
CYP450 inducers include which of the following?
A) Valproate and isoniazid
B) Barbiturates, St. John's Wort, and carbamazepine
C) Ketoconazole and grapefruit juice
D) Amiodarone and chloramphenicol
Correct Answer: B) Barbiturates, St. John's Wort, and carbamazepine
Rationale: CYP450 inducers include barbiturates, St. John's Wort, carbamazepine, rifampin,
phenytoin, griseofulvin, and sulfonylureas. Inhibitors include valproate, isoniazid, amiodarone,
ketoconazole, and grapefruit juice .
Exemplify-Style Practice Questions & Answer Guide
Question 1
A patient is prescribed a drug that is a weak base with a pKa of 8.4. In which part of the body
will this drug be most highly ionized?
A) Small intestine (pH 7.4)
B) Stomach (pH 1.5-3.5)
C) Blood (pH 7.35-7.45)
D) Urine (pH 5.0-8.0)
Correct Answer: B) Stomach (pH 1.5-3.5)
Rationale: Weak bases are more ionized in acidic environments (low pH). Ionized drugs are
poorly absorbed across lipid membranes. The stomach's low pH favors ionization of weak bases,
making them less likely to be absorbed. Weak acids are better absorbed in the stomach; weak
bases are better absorbed in the small intestine.
Question 2
Which pharmacokinetic process is most affected by first-pass metabolism?
A) Distribution
B) Metabolism
C) Oral absorption
D) Renal excretion
Correct Answer: C) Oral absorption
,Rationale: First-pass metabolism occurs in the liver and gut wall after oral administration,
reducing the amount of active drug reaching systemic circulation. Drugs with extensive first-pass
effect often require higher oral doses or alternative routes (IV, sublingual, transdermal) .
Question 3
A drug with a narrow therapeutic index (e.g., lithium, warfarin) requires:
A) Less frequent monitoring
B) More frequent monitoring of serum drug levels
C) Administration with food only
D) Use only in pediatric patients
Correct Answer: B) More frequent monitoring of serum drug levels
Rationale: Drugs with a narrow therapeutic index have a small margin between therapeutic and
toxic doses. Frequent monitoring of serum levels is required to ensure the dose remains within
the safe and effective window .
Question 4
What does bioavailability refer to?
A) The amount of drug that reaches systemic circulation unchanged
B) The rate at which drug is metabolized
C) The time it takes for drug to be eliminated
D) The volume of distribution
Correct Answer: A) The amount of drug that reaches systemic circulation unchanged
,Rationale: Bioavailability (F) is the fraction of the administered dose that reaches systemic
circulation unchanged. IV drugs have 100% bioavailability; oral drugs have variable
bioavailability due to incomplete absorption and first-pass metabolism .
Question 5
The time required for half of a drug concentration to be eliminated from the body is called:
A) Peak level
B) Bioavailability
C) Half-life
D) Potency
Correct Answer: C) Half-life
Rationale: Half-life determines dosing intervals and duration of action. It is the time required for
the drug concentration in the body to be reduced by 50% .
Question 6
What is the CYP450 (cytochrome P450) system?
A) Kidney enzyme system where medications are excreted
B) Liver enzyme system where medications are metabolized
C) GI tract system where medications are absorbed
D) Blood system where medications are distributed
Correct Answer: B) Liver enzyme system where medications are metabolized
Rationale: The CYP450 system is a liver enzyme system where medications are metabolized.
Enzymes can either be inducers or inhibitors and create drug-drug interactions .
, Question 7
Which statement about CYP450 inducers is correct?
A) They slow down metabolism of drugs
B) They speed up metabolism of drugs, causing drugs to have lesser effect
C) They have no effect on drug metabolism
D) They only affect IV medications
Correct Answer: B) They speed up metabolism of drugs, causing drugs to have lesser effect
Rationale: CYP450 inducers speed up metabolism of drugs, meaning the drug is cleared faster
and has a lesser effect. They elevate CYP450 enzyme activity .
Question 8
CYP450 inducers include which of the following?
A) Valproate and isoniazid
B) Barbiturates, St. John's Wort, and carbamazepine
C) Ketoconazole and grapefruit juice
D) Amiodarone and chloramphenicol
Correct Answer: B) Barbiturates, St. John's Wort, and carbamazepine
Rationale: CYP450 inducers include barbiturates, St. John's Wort, carbamazepine, rifampin,
phenytoin, griseofulvin, and sulfonylureas. Inhibitors include valproate, isoniazid, amiodarone,
ketoconazole, and grapefruit juice .
