NUR 641E - Midterm Exam Study Guide.
**Q1. What is the primary difference between Pharmacokinetics and
Pharmacodynamics?**
- **Answer:** Pharmacokinetics is "what the body does to the drug"
(Absorption, Distribution, Metabolism, Excretion), while
Pharmacodynamics is "what the drug does to the body" (receptor
binding and clinical effects) .
**Q2. A patient with liver failure is prescribed a prodrug. Why might
this medication be ineffective?**
- **Answer:** Prodrugs require hepatic metabolism (often via
Cytochrome P450) to convert them into their active form. Liver failure
reduces this conversion, leading to therapeutic failure .
- **Rationale:** Examples of prodrugs include Clopidogrel (Plavix) and
Codeine. If the liver cannot metabolize them, the patient does not
receive the therapeutic benefit.
**Q3. Which route of administration bypasses the first-pass effect
entirely, resulting in 100% bioavailability?**
- **Answer:** Intravenous (IV) administration .
- **Rationale:** The first-pass effect occurs when drugs are absorbed
from the GI tract and metabolized by the liver before reaching systemic
circulation. IV administration places the drug directly into the blood,
bypassing the gut and liver.
,**Q4. How many half-lives does it take for a drug to reach steady
state?**
- **Answer:** Approximately 4 to 5 half-lives .
- **Rationale:** Steady state is achieved when the rate of drug
administration equals the rate of drug elimination. Regardless of dose,
it takes this consistent timeframe to reach equilibrium.
**Q5. A patient is taking Warfarin and starts taking Omeprazole (a
CYP450 inhibitor). What is the potential interaction?**
- **Answer:** Increased Warfarin levels and risk of bleeding .
- **Rationale:** Omeprazole inhibits the cytochrome P450 enzymes
(specifically CYP2C19) that metabolize Warfarin. Inhibition leads to
decreased metabolism and higher drug concentrations.
**Q6. What defines a drug with Zero-Order kinetics?**
- **Answer:** The drug is eliminated at a constant rate per unit time,
regardless of concentration (e.g., Phenytoin, Alcohol, Aspirin in high
doses) .
**Cardiovascular System (Heart Failure, Hypertension,
Anticoagulation)**
**Q7. Which laboratory finding places a patient taking Digoxin at the
highest risk for toxicity?**
- **Answer:** Hypokalemia (low potassium) .
, - **Rationale:** Digoxin blocks the Na+/K+ ATPase pump. Low serum
potassium allows Digoxin to bind more aggressively to the pump,
increasing toxicity even if the digoxin level is "therapeutic."
**Q8. A patient with chronic COPD presents with shortness of breath.
The nurse recalls that these patients rely on what mechanism to
breathe?**
- **Answer:** Hypoxic drive .
- **Rationale:** In chronic COPD, CO2 levels are chronically high, so the
medulla becomes desensitized to CO2. The primary stimulus to breathe
becomes low O2 levels. High-flow oxygen can remove this drive,
causing respiratory depression.
**Q9. Which class of antihypertensives is associated with a dry,
persistent cough and angioedema?**
- **Answer:** ACE Inhibitors (e.g., Lisinopril, Enalapril) .
- **Rationale:** ACE inhibitors prevent the breakdown of bradykinin,
leading to accumulation. Bradykinin causes vasodilation but also
irritates the respiratory tract (cough) and increases vascular
permeability (angioedema).
**Q10. What is the antidote for Warfarin (Coumadin) toxicity?**
- **Answer:** Vitamin K (Phytonadione) .
- **Rationale:** Warfarin is a Vitamin K antagonist. It inhibits the
synthesis of clotting factors II, VII, IX, and X. Administering Vitamin K
reverses this effect.
**Q1. What is the primary difference between Pharmacokinetics and
Pharmacodynamics?**
- **Answer:** Pharmacokinetics is "what the body does to the drug"
(Absorption, Distribution, Metabolism, Excretion), while
Pharmacodynamics is "what the drug does to the body" (receptor
binding and clinical effects) .
**Q2. A patient with liver failure is prescribed a prodrug. Why might
this medication be ineffective?**
- **Answer:** Prodrugs require hepatic metabolism (often via
Cytochrome P450) to convert them into their active form. Liver failure
reduces this conversion, leading to therapeutic failure .
- **Rationale:** Examples of prodrugs include Clopidogrel (Plavix) and
Codeine. If the liver cannot metabolize them, the patient does not
receive the therapeutic benefit.
**Q3. Which route of administration bypasses the first-pass effect
entirely, resulting in 100% bioavailability?**
- **Answer:** Intravenous (IV) administration .
- **Rationale:** The first-pass effect occurs when drugs are absorbed
from the GI tract and metabolized by the liver before reaching systemic
circulation. IV administration places the drug directly into the blood,
bypassing the gut and liver.
,**Q4. How many half-lives does it take for a drug to reach steady
state?**
- **Answer:** Approximately 4 to 5 half-lives .
- **Rationale:** Steady state is achieved when the rate of drug
administration equals the rate of drug elimination. Regardless of dose,
it takes this consistent timeframe to reach equilibrium.
**Q5. A patient is taking Warfarin and starts taking Omeprazole (a
CYP450 inhibitor). What is the potential interaction?**
- **Answer:** Increased Warfarin levels and risk of bleeding .
- **Rationale:** Omeprazole inhibits the cytochrome P450 enzymes
(specifically CYP2C19) that metabolize Warfarin. Inhibition leads to
decreased metabolism and higher drug concentrations.
**Q6. What defines a drug with Zero-Order kinetics?**
- **Answer:** The drug is eliminated at a constant rate per unit time,
regardless of concentration (e.g., Phenytoin, Alcohol, Aspirin in high
doses) .
**Cardiovascular System (Heart Failure, Hypertension,
Anticoagulation)**
**Q7. Which laboratory finding places a patient taking Digoxin at the
highest risk for toxicity?**
- **Answer:** Hypokalemia (low potassium) .
, - **Rationale:** Digoxin blocks the Na+/K+ ATPase pump. Low serum
potassium allows Digoxin to bind more aggressively to the pump,
increasing toxicity even if the digoxin level is "therapeutic."
**Q8. A patient with chronic COPD presents with shortness of breath.
The nurse recalls that these patients rely on what mechanism to
breathe?**
- **Answer:** Hypoxic drive .
- **Rationale:** In chronic COPD, CO2 levels are chronically high, so the
medulla becomes desensitized to CO2. The primary stimulus to breathe
becomes low O2 levels. High-flow oxygen can remove this drive,
causing respiratory depression.
**Q9. Which class of antihypertensives is associated with a dry,
persistent cough and angioedema?**
- **Answer:** ACE Inhibitors (e.g., Lisinopril, Enalapril) .
- **Rationale:** ACE inhibitors prevent the breakdown of bradykinin,
leading to accumulation. Bradykinin causes vasodilation but also
irritates the respiratory tract (cough) and increases vascular
permeability (angioedema).
**Q10. What is the antidote for Warfarin (Coumadin) toxicity?**
- **Answer:** Vitamin K (Phytonadione) .
- **Rationale:** Warfarin is a Vitamin K antagonist. It inhibits the
synthesis of clotting factors II, VII, IX, and X. Administering Vitamin K
reverses this effect.
