NR-226 – Pharmacology Study of medications,
drug classifications, therapeutic effects,
administration techniques, dosage calculations,
adverse reactions, and patient education.
1. A nurse administers a medication that binds to a receptor and produces a
response. This medication is classified as:
• A) Antagonist
• B) Agonist
• C) Partial agonist
• D) Competitive antagonist
Answer: B
Rationale: An agonist binds to a receptor and activates it, producing a
pharmacological response. An antagonist blocks the receptor. Partial agonists
produce a weaker response.
2. A drug has a half-life of 4 hours. How much of the original dose remains in
the body after 12 hours?
• A) 50%
• B) 25%
• C) 12.5%
• D) 6.25%
Answer: C
Rationale: After 1 half-life (4h): 50% remains; after 2 half-lives (8h): 25%; after 3
half-lives (12h): 12.5% remains. Formula: (1/2)^n where n = number of half-lives.
3. Which route of administration has the fastest onset of action?
, • A) Oral
• B) Subcutaneous
• C) Intramuscular
• D) Intravenous
Answer: D
Rationale: Intravenous administration delivers drug directly into bloodstream,
achieving immediate onset. Oral requires absorption; subcutaneous/IM require
absorption from tissue.
4. A patient with liver cirrhosis is prescribed a drug that undergoes extensive
first-pass metabolism. The nurse anticipates that the prescriber will:
• A) Increase the oral dose
• B) Use a parenteral route
• C) Decrease the oral dose
• D) Add a second drug to enhance metabolism
Answer: B
Rationale: First-pass metabolism occurs in the liver. Cirrhosis impairs this, but
using a parenteral route (IV, IM, sublingual) bypasses first-pass effect entirely,
providing predictable levels.
5. A drug's therapeutic index is narrow. This means:
• A) The drug has a wide safety margin
• B) The drug is safe at any dose
• C) There is a small difference between effective and toxic doses
• D) The drug requires no monitoring
Answer: C
Rationale: A narrow therapeutic index means the margin between minimal
effective concentration and toxic concentration is small. These drugs require close
monitoring (e.g., digoxin, warfarin, phenytoin).
,6. A nurse administers naloxone to reverse respiratory depression caused by
morphine. Naloxone is acting as a(n):
• A) Agonist
• B) Partial agonist
• C) Antagonist
• D) Inverse agonist
Answer: C
Rationale: Naloxone is a competitive antagonist at opioid receptors – it binds but
does not activate, blocking morphine's effects and reversing respiratory depression.
7. Which factor increases drug absorption from the gastrointestinal tract?
• A) Presence of food
• B) Increased gastric pH (less acidic)
• C) Increased blood flow to GI tract
• D) Delayed gastric emptying
Answer: C
Rationale: Increased blood flow enhances absorption by maintaining
concentration gradient. Food may delay or enhance depending on drug. Increased
pH (less acidic) reduces absorption of weak acids.
8. A patient is receiving a drug that is highly protein-bound (95%). Another
drug that also binds to albumin is added. The nurse expects:
• A) Decreased free fraction of the first drug
• B) Increased risk of toxicity from the first drug
• C) No change in drug levels
• D) Decreased therapeutic effect
, Answer: B
Rationale: Two highly protein-bound drugs compete for binding sites.
Displacement increases free (unbound) drug concentration, which is
pharmacologically active, increasing risk of toxicity.
9. A drug is excreted primarily by the kidneys. A patient with a creatinine
clearance of 20 mL/min should receive:
• A) A higher dose
• B) A lower dose or longer interval
• C) The same dose as normal renal function
• D) An intravenous loading dose only
Answer: B
Rationale: Reduced renal function decreases drug excretion, leading to
accumulation. The prescriber should reduce dose or prolong dosing interval to
avoid toxicity.
10. Which statement best describes the blood-brain barrier (BBB)?
• A) It allows all drugs to enter the brain freely
• B) It is impermeable to lipid-soluble drugs
• C) It prevents many water-soluble drugs from entering the brain
• D) It only affects pediatric patients
Answer: C
Rationale: The BBB consists of tight junctions. Lipid-soluble drugs cross
easily; water-soluble and large molecules have difficulty crossing unless they use
transport systems.
SECTION 2: DOSAGE CALCULATIONS (Questions 11-20)
11. The order reads: Heparin 5,000 units subcutaneously daily. Available:
Heparin 10,000 units/mL. How many mL will the nurse administer?
drug classifications, therapeutic effects,
administration techniques, dosage calculations,
adverse reactions, and patient education.
1. A nurse administers a medication that binds to a receptor and produces a
response. This medication is classified as:
• A) Antagonist
• B) Agonist
• C) Partial agonist
• D) Competitive antagonist
Answer: B
Rationale: An agonist binds to a receptor and activates it, producing a
pharmacological response. An antagonist blocks the receptor. Partial agonists
produce a weaker response.
2. A drug has a half-life of 4 hours. How much of the original dose remains in
the body after 12 hours?
• A) 50%
• B) 25%
• C) 12.5%
• D) 6.25%
Answer: C
Rationale: After 1 half-life (4h): 50% remains; after 2 half-lives (8h): 25%; after 3
half-lives (12h): 12.5% remains. Formula: (1/2)^n where n = number of half-lives.
3. Which route of administration has the fastest onset of action?
, • A) Oral
• B) Subcutaneous
• C) Intramuscular
• D) Intravenous
Answer: D
Rationale: Intravenous administration delivers drug directly into bloodstream,
achieving immediate onset. Oral requires absorption; subcutaneous/IM require
absorption from tissue.
4. A patient with liver cirrhosis is prescribed a drug that undergoes extensive
first-pass metabolism. The nurse anticipates that the prescriber will:
• A) Increase the oral dose
• B) Use a parenteral route
• C) Decrease the oral dose
• D) Add a second drug to enhance metabolism
Answer: B
Rationale: First-pass metabolism occurs in the liver. Cirrhosis impairs this, but
using a parenteral route (IV, IM, sublingual) bypasses first-pass effect entirely,
providing predictable levels.
5. A drug's therapeutic index is narrow. This means:
• A) The drug has a wide safety margin
• B) The drug is safe at any dose
• C) There is a small difference between effective and toxic doses
• D) The drug requires no monitoring
Answer: C
Rationale: A narrow therapeutic index means the margin between minimal
effective concentration and toxic concentration is small. These drugs require close
monitoring (e.g., digoxin, warfarin, phenytoin).
,6. A nurse administers naloxone to reverse respiratory depression caused by
morphine. Naloxone is acting as a(n):
• A) Agonist
• B) Partial agonist
• C) Antagonist
• D) Inverse agonist
Answer: C
Rationale: Naloxone is a competitive antagonist at opioid receptors – it binds but
does not activate, blocking morphine's effects and reversing respiratory depression.
7. Which factor increases drug absorption from the gastrointestinal tract?
• A) Presence of food
• B) Increased gastric pH (less acidic)
• C) Increased blood flow to GI tract
• D) Delayed gastric emptying
Answer: C
Rationale: Increased blood flow enhances absorption by maintaining
concentration gradient. Food may delay or enhance depending on drug. Increased
pH (less acidic) reduces absorption of weak acids.
8. A patient is receiving a drug that is highly protein-bound (95%). Another
drug that also binds to albumin is added. The nurse expects:
• A) Decreased free fraction of the first drug
• B) Increased risk of toxicity from the first drug
• C) No change in drug levels
• D) Decreased therapeutic effect
, Answer: B
Rationale: Two highly protein-bound drugs compete for binding sites.
Displacement increases free (unbound) drug concentration, which is
pharmacologically active, increasing risk of toxicity.
9. A drug is excreted primarily by the kidneys. A patient with a creatinine
clearance of 20 mL/min should receive:
• A) A higher dose
• B) A lower dose or longer interval
• C) The same dose as normal renal function
• D) An intravenous loading dose only
Answer: B
Rationale: Reduced renal function decreases drug excretion, leading to
accumulation. The prescriber should reduce dose or prolong dosing interval to
avoid toxicity.
10. Which statement best describes the blood-brain barrier (BBB)?
• A) It allows all drugs to enter the brain freely
• B) It is impermeable to lipid-soluble drugs
• C) It prevents many water-soluble drugs from entering the brain
• D) It only affects pediatric patients
Answer: C
Rationale: The BBB consists of tight junctions. Lipid-soluble drugs cross
easily; water-soluble and large molecules have difficulty crossing unless they use
transport systems.
SECTION 2: DOSAGE CALCULATIONS (Questions 11-20)
11. The order reads: Heparin 5,000 units subcutaneously daily. Available:
Heparin 10,000 units/mL. How many mL will the nurse administer?
