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WorksheetsPharmacokinetics, Pharmacodynamics Test
Total questions: 50
Worksheet time: 50mins
A nurse administers an IV antibiotic to a patient. After 5 hours, the drug concentration has decreased to 25% of the initial value. What concept best explains this observation?
First-order kinetics
Zero-order kinetics
Saturation kinetics
Therapeutic window
A patient with cirrhosis shows a prolonged half-life for a prescribed medication. What is the most likely explanation?
Increased metabolism
Decreased hepatic clearance
Enhanced renal excretion
Decreased drug absorption
A nurse is caring for a patient receiving morphine. She notes that the drug is metabolized by conjugation. What phase of metabolism is primarily involved?
Phase I oxidation
Phase II conjugation
Phase I reduction
Cytochrome inhibition
A nursing student learns that a drug is eliminated via zero-order kinetics. What is the best interpretation of this?
A fixed percentage is eliminated per hour
A fixed amount is eliminated per hour
Elimination increases with concentration
Half-life remains constant regardless of dose
A patient with renal failure is prescribed digoxin. Which pharmacokinetic parameter should the nurse monitor closely?
Volume of distribution
Protein binding
Clearance
Bioavailability
A nurse explains to a patient that a loading dose of a drug is given. What is the main purpose of this loading dose?
To achieve therapeutic levels rapidly
To improve drug metabolism
To reduce toxicity risk
To enhance drug excretion
A patient receiving phenytoin shows signs of toxicity despite a normal dose. Which kinetic principle likely explains this?
First-order kinetics
Linear kinetics
Zero-order kinetics
Renal excretion variability
After administering a drug, the nurse observes that the plasma concentration rises and reaches a plateau after several doses. What is this plateau called?
Maximum effect
Drug saturation
Steady-state concentration
Therapeutic range
A nurse is giving rifampin with antiretroviral therapy. What is the likely pharmacokinetic consequence?
Increased plasma drug levels
Decreased effectiveness due to enzyme induction
No effect on drug levels
Enhanced drug absorption
A patient is prescribed a drug that is a substrate of CYP3A4. What advice should the nurse give regarding grapefruit juice?
It helps drug elimination
Avoid it as it may increase drug toxicity
It enhances absorption safely
It prevents first-pass metabolism
A nurse administers oral medication to a patient. She explains that some of the drug is lost during first-pass metabolism. Where does this primarily occur?
Kidney
Brain
Pancreas
Liver
In a case of phenobarbital overdose, what nursing intervention helps enhance drug excretion?
Alkalinization of urine
Acidification of urine
Increasing lipid solubility
Blocking CYP450
A nurse adjusts the dose of a lipid-soluble drug for a patient with high body fat. What pharmacokinetic factor is being considered?
Volume of distribution
Renal clearance
Hepatic metabolism
Protein binding
A patient is given a highly protein-bound drug. What will likely happen if the patient has low albumin levels?
Decreased free drug
Faster elimination
Increased free drug concentration
Slower onset of action
A nurse needs to administer a drug with a narrow therapeutic window. What is the safest approach?
Give a higher dose initially
Monitor drug levels closely
Use alternative routes
Extend dosing intervals
A patient taking codeine reports no pain relief. The nurse suspects the issue lies in metabolism. Which enzyme is likely involved?
CYP3A4
CYP2D6
CYP2E1
CYP1A2
A nurse administers a drug every 12 hours. The drug has a half-life of 12 hours. What will happen to the drug concentration over time?
It will stay the same
It will accumulate and reach steady state
It will be eliminated immediately
It will continuously rise without limit
A nurse explains that a drug is eliminated by first-order kinetics. What does this mean?
A fixed dose is eliminated every hour
A constant fraction is eliminated per time
Elimination is independent of drug level
The drug is not eliminated at all
A nurse is calculating the maintenance dose for a drug. Which parameter is NOT needed?
Target plasma concentration
Drug clearance
Bioavailability
Half-life
After stopping a continuous drug infusion, how long will it take for the drug to be almost completely eliminated (about 95%)?
1 half-life
2 half-lives
5 half-lives
10 half-lives
A nurse sees that a drug has a very short half-life. What does this mean for dosing?
More frequent dosing is required
A loading dose is unnecessary
The drug is not absorbed well
It can be dosed once daily
A drug metabolized by CYP2C19 is given to a poor metabolizer. What outcome is most likely?
Reduced efficacy or increased toxicity
Enhanced clearance
Decreased plasma levels
Faster therapeutic effect
A nurse is administering an oral drug that has poor bioavailability. Which factor contributes most to this issue?
First-pass metabolism
High water solubility
Short half-life
Increased renal excretion
In a patient with heart failure and low hepatic perfusion, what is the expected effect on drug metabolism?
Decreased drug clearance
Increased drug half-life
Increased absorption
No change in pharmacokinetics
A nurse is reviewing the effect of enzyme inducers like phenobarbital on drug levels. What is the expected result?
Increased plasma concentration
Decreased therapeutic effect
Longer half-life
Reduced renal excretion
A nurse is administering a medication that is a full agonist. What effect should the nurse anticipate?
It will bind to the receptor and produce a maximal biologic response.
It will bind to the receptor but produce no biologic response.
It will only partially activate the receptor.
It will inhibit the receptor activity below the baseline level.
A patient is prescribed phenylephrine, a full agonist at α1-adrenoceptors. What is the expected effect on blood pressure?
Increased blood pressure due to vasoconstriction.
Decreased blood pressure due to vasodilation
No change in blood pressure.
Fluctuating blood pressure with no predictable response.
A nurse is caring for a patient receiving aripiprazole, a partial dopamine agonist. Which best describes its therapeutic advantage?
It fully blocks dopamine and reduces all side effects.
It modulates dopamine activity, reducing overactivity and enhancing underactivity.
It stimulates dopamine receptors to the maximum extent.
It increases dopamine in all brain pathways equally.
A patient receives a medication that binds to a receptor and reduces receptor activity below baseline. The nurse recognizes this drug as:
A full agonist
A partial agonist
An inverse agonist
A competitive antagonist
A nurse is reviewing a medication that binds to a receptor without activating it and prevents agonist binding. What type of drug is this?
Inverse agonist
Competitive antagonist
Allosteric agonist
Partial agonist
A patient is taking terazosin, a competitive antagonist. Which change would the nurse expect on the dose-response curve of an agonist?
Decreased Emax
Shift to the left
Increased EC50 without change in Emax
Irreversible inhibition of the receptor
The nurse administers a noncompetitive antagonist. What should the nurse expect in terms of drug efficacy?
A decrease in the maximal response (Emax)
An increase in EC50 with no change in Emax
A reversible inhibition of agonist binding
A short duration of drug-receptor binding
What is the expected result of an allosteric antagonist binding to a receptor?
Increased agonist binding
Decreased Emax without changing EC50
Decreased EC50
Increased receptor activation
Which type of antagonism involves activation of a different receptor to produce an opposing physiologic effect?
Allosteric antagonism
Functional (physiologic) antagonism
Competitive antagonism
Irreversible antagonism
Epinephrine is used to counteract histamine-induced bronchoconstriction. This is an example of:
Allosteric antagonism
Competitive antagonism
Functional (physiologic) antagonism
Inverse agonism
A nurse explains to a student that partial agonists may act as antagonists in the presence of full agonists Because:
They increase the number of active receptors.
They have higher efficacy.
They displace full agonists and reduce the maximal response.
They increase intrinsic activity beyond that of full agonists.
The nurse is monitoring a patient taking two drugs: one is a full agonist and the other is a partial agonist for the same receptor. What outcome is expected?
Enhanced full agonist activity
Inhibition of the partial agonist by the full agonist
Reduced overall receptor response
No interaction occurs
A medication has an intrinsic activity of zero and blocks the action of an agonist. What type of drug is it?
Inverse agonist
Antagonist
Full agonist
Partial agonist
A nurse understands that inverse agonists differ from antagonists Because:
They activate more receptors.
They have no effect on receptor activity.
They reduce receptor activity below baseline.
They compete reversibly with agonists.
Which property does not change when a competitive antagonist is administered with an agonist?
Drug potency
EC50 value
Maximum efficacy (Emax)
Required drug concentration
Which scenario best illustrates the concept of therapeutic index (TI)?
A drug with a TI of 1 is very safe.
A drug with a high TI has a wider margin between effective and toxic doses.
Drugs with low TI can be given freely without monitoring.
TI is unrelated to drug safety.
Which drug would require careful dose monitoring due to a low therapeutic index?
Warfarin
Penicillin
Ibuprofen
Acetaminophen
A patient receives penicillin for an infection. The nurse recognizes this as a safe drug because:
It is not absorbed systemically.
It binds irreversibly to its target.
It has a large therapeutic index.
It is metabolized slowly by the liver.
What happens to the dose-response curve in the presence of an irreversible antagonist?
Rightward shift with no change in Emax
Decrease in Emax with no shift in EC50
No change in the curve
Leftward shift with increased potency
A nurse administering a drug that demonstrates constitutive receptor activity should know that:
Only agonists can activate the receptor.
Receptors are inactive without drug binding.
Receptors can spontaneously activate without ligands.
Inverse agonists will further enhance activity.
Which best describes a quantal dose-response relationship?
The effect is graded and varies in intensity.
The effect either occurs or does not in individuals.
It measures the rate of receptor binding.
It is used only for pediatric dosing.
During a medication review, the nurse identifies that a drug has a high ED50. What does this imply?
It is highly toxic.
It is rapidly absorbed.
It requires a larger dose to achieve 50% effectiveness.
It cannot be used with other medications.
A drug trial shows the TD50 of a drug is close to the ED50. The nurse understands this means:
The drug has a narrow therapeutic index and requires close monitoring.
The drug is very safe.
The drug is not effective at all.
The drug has no side effects.
A drug has a TI of 10. What does this indicate?
The drug is extremely toxic.
The drug has a wide margin of safety.
The drug is ineffective in most people.
The drug should only be given in hospitals.
Why is it important for nurses to understand pharmacodynamic principles like receptor activity, agonism, and antagonism?
To know how to write prescriptions
To anticipate drug effects and prevent adverse reactions
To determine pricing and availability
To manage patient insurance claims
