Pharmacokinetics and pharmacodynamics > Pharmacology
Exam Review
Pharmacokinetics
Total Questions : 10
Showing 10 questions, Sign in for moreA nurse is preparing to administer a medication that has a narrow therapeutic index. What action should the nurse take?
Explanation
A medication with a narrow therapeutic index has a small margin of safety between its therapeutic and toxic doses. The nurse should hold the medication and notify the provider to ensure that the client’s drug levels are within the therapeutic range and to avoid potential toxicity.
a. Administering the medication as prescribed could result in toxicity if the client’s drug levels are not within the therapeutic range.
c. Administering half the dose of the medication is not appropriate without consulting the provider and monitoring the client’s drug levels.
d. Administering the medication with food or milk may affect its absorption but does not prevent potential toxicity.
A nurse is preparing to administer a medication that undergoes extensive first-pass metabolism. What route of administration should be used?
Explanation
First-pass metabolism refers to the metabolism of a drug by the liver before it reaches systemic circulation. Drugs that undergo extensive first-pass metabolism have a lower bioavailability when administered orally because a significant portion of the drug is metabolized before it reaches systemic circulation. Intravenous administration bypasses first-pass metabolism and delivers the drug directly into systemic circulation.
a. Oral administration would result in lower bioavailability due to first-pass metabolism.
c. Subcutaneous administration may also be subject to first-pass metabolism.
d. Intramuscular administration may also be subject to first-pass metabolism.
A nurse is preparing to administer a lipophilic medication to a client with a high body fat percentage. What should the nurse consider?
Explanation
Lipophilic medications are soluble in fat and can accumulate in adipose tissue, reducing their concentration in plasma and potentially reducing their therapeutic effect. A client with a high body fat percentage may require a higher dose of a lipophilic medication to achieve therapeutic levels.
b. The client may require a higher, not lower, dose of the medication due to accumulation in adipose tissue.
c. More frequent dosing may not be necessary if an appropriate dose is administered.
d. The client’s body fat percentage can affect pharmacokinetics by altering distribution of lipophilic medications.
A nurse is preparing to administer a weakly acidic medication to a client with an elevated gastric pH due to antacid use. What should the nurse consider?
Explanation
Weakly acidic medications are more readily absorbed in an acidic environment because they are more likely to be in their non-ionized, lipid-soluble form which can easily cross cell membranes and enter systemic circulation. An elevated gastric pH due to antacid use can reduce absorption of weakly acidic medications by increasing ionization and reducing lipid solubility.
a. The medication will have decreased, not increased, absorption in an alkaline environment due to increased ionization.
c. The antacid can affect absorption by altering gastric pH and increasing ionization of weakly acidic medications.
d. The antacid can affect absorption but does not directly affect excretion of weakly acidic medications.
A nurse is preparing to administer a prodrug that requires activation by hepatic enzymes.What should be considered when administering this drug?
Explanation
A prodrug is an inactive compound that requires conversion into its active form by metabolic processes such as hepatic enzyme activation.Giving a prodrug with an enzyme inducer can increase the activity of the hepatic enzymes responsible for converting the prodrug into its active form, potentially increasing its efficacy.
a.Giving the drug with food may affect its absorption but does not directly affect its activation by hepatic enzymes.
b.Giving the drug with food may affect its absorption but does not directly affect its activation by hepatic enzymes.
c.Giving the drug with an enzyme inducer, not an enzyme inhibitor, can increase its efficacy by increasing hepatic enzyme activity.
A nurse is preparing to administer a medication that is primarily excreted by the kidneys.What should be considered when administering this drug to a client with renal impairment?
Explanation
Medications that are primarily excreted by the kidneys can accumulate in clients with renal impairment, potentially leading to toxicity.A client with renal impairment may require a lower dose of a medication that is primarily excreted by the kidneys to avoid accumulation and toxicity.
a.The client may require a lower, not higher, dose of the medication due to reduced renal excretion.
c.More frequent dosing may not be necessary if an appropriate dose is administered.
d.The client’s renal function can affect pharmacokinetics by altering excretion of medications that are primarily eliminated by the kidneys.
A nurse is preparing to administer a medication that is highly protein bound.What should be considered when administering this drug to a client with hypoalbuminemia?
Explanation
Medications that are highly protein bound bind to plasma proteins such as albumin, reducing their free fraction and potentially reducing their therapeutic effect.A client with hypoalbuminemia may have an increased free fraction of a highly protein-bound medication due to reduced protein binding, potentially increasing its therapeutic effect.
b.The client may have an increased, not decreased, free fraction of the drug due to reduced protein binding.
c.An increased volume of distribution may occur if protein binding is reduced, but this is not directly related to hypoalbuminemia.
d.The client’s albumin levels can affect pharmacokinetics by altering protein binding of highly protein-bound medications.
A nurse is preparing to administer a medication that undergoes enterohepatic recirculation.What should be considered when administering this drug?
Explanation
Enterohepatic recirculation refers to the process by which a drug or its metabolites are excreted into bile, reabsorbed from the intestines, and returned to the liver.Medications that undergo enterohepatic recirculation can have a longer half-life due to repeated reabsorption and recirculation.
a.The drug will have a longer, not shorter, half-life due to repeated reabsorption and recirculation.
c.Enterohepatic recirculation can affect half-life but does not directly affect bioavailability.
d.Enterohepatic recirculation can affect half-life but does not directly affect bioavailability.
A nurse is preparing to administer a medication that induces CYP450 enzymes.What should be considered when administering this drug with other medications?
Explanation
CYP450 enzymes are responsible for metabolizing many medications.Induction of CYP450 enzymes can increase their activity and accelerate metabolism of other medications that are substrates for these enzymes, potentially reducing their therapeutic effect and increasing the risk of drug interactions.
b.There is an increased, not decreased, risk of drug interactions due to accelerated metabolism of other medications.
c.There is an increased risk of drug interactions due to accelerated metabolism of other medications.
d.CYP450 induction can affect pharmacokinetics by altering metabolism of other medications that are substrates for these enzymes.
A nurse is preparing to administer a medication that inhibits P-glycoprotein.What should be considered when administering this drug with other medications?
Explanation
P-glycoprotein is a membrane protein that pumps certain drugs out of cells and can affect their absorption, distribution, and elimination. Inhibition of P-glycoprotein can increase the concentration of other medications that are substrates for this protein, potentially increasing their therapeutic effect and the risk of drug interactions.
b. There is an increased, not decreased, risk of drug interactions due to increased concentration of other medications that are substrates for P-glycoprotein.
c. There is an increased risk of drug interactions due to increased concentration of other medications that are substrates for P-glycoprotein.
d. P-glycoprotein inhibition can affect pharmacokinetics by altering absorption, distribution, and elimination of other medications that are substrates for this protein.
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