NUR 1141 Introduction to
Pharmacology – Final Exam Mastery:
Practice Questions with Answers &
Clinical Rationales
1. A patient is prescribed a medication that has a high first-pass effect.
The nurse anticipates that this drug will be administered via which
route to avoid this effect?
Answer: Intravenous (IV) or sublingual.
Rationale: The first-pass effect is the metabolism of a drug by the liver
before it reaches systemic circulation. Drugs given orally are absorbed from
the GI tract and travel directly to the liver via the portal vein, where a
significant portion can be inactivated. IV and sublingual routes bypass the
portal circulation, thus avoiding the first-pass effect.
2. A medication has a half-life of 4 hours. How much of the drug will
remain in the body after 16 hours if the initial dose was 200 mg?
Answer: 12.5 mg.
Rationale: After one half-life (4 hrs), 100 mg remains. After 8 hrs, 50 mg
remains. After 12 hrs, 25 mg remains. After 16 hrs (four half-lives), 12.5 mg
remains. This demonstrates the exponential decay of drug concentration.
3. The nurse is preparing to administer a drug that is known to be
highly protein-bound. Which patient condition would most
significantly increase the risk of drug toxicity?
Answer: Hypoalbuminemia (low serum albumin).
,Rationale: Drugs bind to plasma proteins like albumin, which act as a
"reservoir" and keep the drug inactive. If a patient has low albumin, there
are fewer binding sites, leading to a higher concentration of free, active
drug in the circulation. This increases the risk of toxicity.
4. A patient's medication is primarily metabolized by the CYP3A4
enzyme system. The nurse is aware that administering this drug with
grapefruit juice will likely result in which effect?
Answer: Increased drug levels and risk of toxicity.
Rationale: Grapefruit juice inhibits the CYP3A4 enzyme system in the liver
and GI tract. When the enzyme that metabolizes a drug is inhibited, the
drug is broken down more slowly, leading to higher-than-expected serum
levels and an increased risk of adverse effects.
5. What is the primary site of drug metabolism in the body?
Answer: The liver.
Rationale: The liver contains most of the enzyme systems, such as the
cytochrome P450 system, responsible for biotransforming (metabolizing)
drugs into more water-soluble compounds for easier excretion. Other sites
include the kidneys, lungs, and intestinal mucosa, but the liver is the main
organ.
6. The nurse is reviewing a patient's medication list and notes that two
drugs are agonists at the same receptor. Which statement best
describes the action of these two drugs?
Answer: They both bind to the receptor and produce a response.
Rationale: An agonist is a drug that binds to a receptor and activates it,
producing a cellular response. If two drugs are agonists at the same
receptor, they will both elicit a response, and their combined effect may be
additive or synergistic.
,7. A patient is receiving a drug that acts as a competitive antagonist.
The nurse understands that this drug will:
Answer: Bind to the receptor and prevent the agonist from binding,
producing no effect.
Rationale: A competitive antagonist binds reversibly to the same receptor
site as the agonist, blocking the agonist from binding. Because it does not
activate the receptor, it produces no effect. Increasing the concentration of
the agonist can overcome this blockade.
8. The therapeutic index of a drug is narrow. What implication does
this have for the patient's nursing care?
Answer: The patient must be closely monitored for signs of toxicity, and
serum drug levels must be drawn frequently.
Rationale: The therapeutic index is the ratio of the toxic dose to the
therapeutic dose. A narrow therapeutic index means there is a small margin
of safety. Even a slight increase in the dose can lead to toxic effects,
necessitating careful monitoring and dose adjustment based on serum
drug levels.
9. What is the best description of pharmacokinetics?
Answer: What the body does to the drug.
Rationale: Pharmacokinetics describes the movement of drugs through the
body, encompassing the four processes of absorption, distribution,
metabolism, and excretion (ADME). It focuses on how the body affects the
drug's concentration over time.
10. What is the best description of pharmacodynamics?
Answer: What the drug does to the body.
Rationale: Pharmacodynamics describes the biochemical and physiological
effects of drugs on the body. It focuses on the mechanism of action, the
drug-receptor interaction, and the resulting therapeutic and adverse
effects.
, 11. An order is written for 500 mg of a medication. The available
medication is in a liquid concentration of 250 mg/5 mL. How many mL
will the nurse administer?
Answer: 10 mL.
Rationale: Set up a proportion: 250 mg / 5 mL = 500 mg / X mL. Cross-
multiply to solve for X: 250X = 2500. X = 10 mL. The nurse would
administer 10 mL.
12. A child weighs 22 lbs. The physician orders a medication with a
dose of 10 mg/kg/day in divided doses. What is the child's weight in
kg, and what is the total daily dose?
Answer: 10 kg; 100 mg/day.
Rationale: To convert pounds to kilograms, divide the weight in pounds by
2.2. 22 lbs / 2.2 = 10 kg. The total daily dose is calculated by multiplying the
weight in kg by the dose per kg: 10 kg * 10 mg/kg = 100 mg/day.
13. The nurse is evaluating a patient for a potential allergic reaction to
a new antibiotic. Which finding would be considered a mild, localized
reaction versus a severe, systemic one?
Answer: Mild: localized rash or urticaria; Severe: anaphylaxis.
Rationale: A mild allergic reaction can present as a localized rash, hives
(urticaria), or pruritus. A severe, systemic, life-threatening reaction is
anaphylaxis, which involves respiratory distress, hypotension, and
angioedema.
14. A patient has been taking a medication for several months and
notices it is no longer as effective. This is most likely due to which
phenomenon?
Answer: Tolerance.
Rationale: Tolerance is a decreased response to a drug that occurs over
time, requiring a higher dose to achieve the same therapeutic effect. This is
Pharmacology – Final Exam Mastery:
Practice Questions with Answers &
Clinical Rationales
1. A patient is prescribed a medication that has a high first-pass effect.
The nurse anticipates that this drug will be administered via which
route to avoid this effect?
Answer: Intravenous (IV) or sublingual.
Rationale: The first-pass effect is the metabolism of a drug by the liver
before it reaches systemic circulation. Drugs given orally are absorbed from
the GI tract and travel directly to the liver via the portal vein, where a
significant portion can be inactivated. IV and sublingual routes bypass the
portal circulation, thus avoiding the first-pass effect.
2. A medication has a half-life of 4 hours. How much of the drug will
remain in the body after 16 hours if the initial dose was 200 mg?
Answer: 12.5 mg.
Rationale: After one half-life (4 hrs), 100 mg remains. After 8 hrs, 50 mg
remains. After 12 hrs, 25 mg remains. After 16 hrs (four half-lives), 12.5 mg
remains. This demonstrates the exponential decay of drug concentration.
3. The nurse is preparing to administer a drug that is known to be
highly protein-bound. Which patient condition would most
significantly increase the risk of drug toxicity?
Answer: Hypoalbuminemia (low serum albumin).
,Rationale: Drugs bind to plasma proteins like albumin, which act as a
"reservoir" and keep the drug inactive. If a patient has low albumin, there
are fewer binding sites, leading to a higher concentration of free, active
drug in the circulation. This increases the risk of toxicity.
4. A patient's medication is primarily metabolized by the CYP3A4
enzyme system. The nurse is aware that administering this drug with
grapefruit juice will likely result in which effect?
Answer: Increased drug levels and risk of toxicity.
Rationale: Grapefruit juice inhibits the CYP3A4 enzyme system in the liver
and GI tract. When the enzyme that metabolizes a drug is inhibited, the
drug is broken down more slowly, leading to higher-than-expected serum
levels and an increased risk of adverse effects.
5. What is the primary site of drug metabolism in the body?
Answer: The liver.
Rationale: The liver contains most of the enzyme systems, such as the
cytochrome P450 system, responsible for biotransforming (metabolizing)
drugs into more water-soluble compounds for easier excretion. Other sites
include the kidneys, lungs, and intestinal mucosa, but the liver is the main
organ.
6. The nurse is reviewing a patient's medication list and notes that two
drugs are agonists at the same receptor. Which statement best
describes the action of these two drugs?
Answer: They both bind to the receptor and produce a response.
Rationale: An agonist is a drug that binds to a receptor and activates it,
producing a cellular response. If two drugs are agonists at the same
receptor, they will both elicit a response, and their combined effect may be
additive or synergistic.
,7. A patient is receiving a drug that acts as a competitive antagonist.
The nurse understands that this drug will:
Answer: Bind to the receptor and prevent the agonist from binding,
producing no effect.
Rationale: A competitive antagonist binds reversibly to the same receptor
site as the agonist, blocking the agonist from binding. Because it does not
activate the receptor, it produces no effect. Increasing the concentration of
the agonist can overcome this blockade.
8. The therapeutic index of a drug is narrow. What implication does
this have for the patient's nursing care?
Answer: The patient must be closely monitored for signs of toxicity, and
serum drug levels must be drawn frequently.
Rationale: The therapeutic index is the ratio of the toxic dose to the
therapeutic dose. A narrow therapeutic index means there is a small margin
of safety. Even a slight increase in the dose can lead to toxic effects,
necessitating careful monitoring and dose adjustment based on serum
drug levels.
9. What is the best description of pharmacokinetics?
Answer: What the body does to the drug.
Rationale: Pharmacokinetics describes the movement of drugs through the
body, encompassing the four processes of absorption, distribution,
metabolism, and excretion (ADME). It focuses on how the body affects the
drug's concentration over time.
10. What is the best description of pharmacodynamics?
Answer: What the drug does to the body.
Rationale: Pharmacodynamics describes the biochemical and physiological
effects of drugs on the body. It focuses on the mechanism of action, the
drug-receptor interaction, and the resulting therapeutic and adverse
effects.
, 11. An order is written for 500 mg of a medication. The available
medication is in a liquid concentration of 250 mg/5 mL. How many mL
will the nurse administer?
Answer: 10 mL.
Rationale: Set up a proportion: 250 mg / 5 mL = 500 mg / X mL. Cross-
multiply to solve for X: 250X = 2500. X = 10 mL. The nurse would
administer 10 mL.
12. A child weighs 22 lbs. The physician orders a medication with a
dose of 10 mg/kg/day in divided doses. What is the child's weight in
kg, and what is the total daily dose?
Answer: 10 kg; 100 mg/day.
Rationale: To convert pounds to kilograms, divide the weight in pounds by
2.2. 22 lbs / 2.2 = 10 kg. The total daily dose is calculated by multiplying the
weight in kg by the dose per kg: 10 kg * 10 mg/kg = 100 mg/day.
13. The nurse is evaluating a patient for a potential allergic reaction to
a new antibiotic. Which finding would be considered a mild, localized
reaction versus a severe, systemic one?
Answer: Mild: localized rash or urticaria; Severe: anaphylaxis.
Rationale: A mild allergic reaction can present as a localized rash, hives
(urticaria), or pruritus. A severe, systemic, life-threatening reaction is
anaphylaxis, which involves respiratory distress, hypotension, and
angioedema.
14. A patient has been taking a medication for several months and
notices it is no longer as effective. This is most likely due to which
phenomenon?
Answer: Tolerance.
Rationale: Tolerance is a decreased response to a drug that occurs over
time, requiring a higher dose to achieve the same therapeutic effect. This is
