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.
