Physician Assistants – 2nd Edition Study Guide
Chapter 1: Introduction to Pharmacology: Drug Regulation & Approval
1. Question: What is the difference between a drug's chemical name, generic name, and
trade name?
ANSWER ✓ The chemical name describes the drug's atomic and molecular structure.
The generic name (nonproprietary name) is the official, simplified name assigned to the
drug. The trade name (proprietary name) is the brand name given by the manufacturer.
2. Question: What are the four phases of clinical trials for new drug approval?
ANSWER ✓ Phase I tests safety and pharmacokinetics in healthy volunteers. Phase II
assesses effectiveness and further evaluates safety in a small patient population. Phase
III confirms efficacy, monitors adverse reactions, and compares it to standard treatments
in a large patient group. Phase IV is post-marketing surveillance after the drug is
released to the public.
3. Question: What is the primary purpose of the Black Box Warning?
ANSWER ✓ It is the strongest warning required by the FDA to alert prescribers and
patients to potentially life-threatening or other serious adverse effects associated with a
drug.
Chapter 2: Pharmacokinetics & Pharmacodynamics
4. Question: Define the four basic processes of pharmacokinetics (ADME).
ANSWER ✓ Absorption (the movement of the drug from its site of administration into
the blood), Distribution (the movement of the drug throughout the body), Metabolism
(the enzymatic alteration of drug structure, primarily in the liver), and Excretion (the
removal of drugs from the body, primarily by the kidneys).
5. Question: What is the first-pass effect?
ANSWER ✓ It is the rapid hepatic inactivation of certain oral drugs as they pass through
the liver after being absorbed from the GI tract, significantly reducing their
bioavailability.
6. Question: How does protein binding affect drug distribution and activity?
ANSWER ✓ Only the unbound (free) fraction of a drug is pharmacologically active.
Drugs that are highly protein-bound can compete for binding sites, potentially
displacing each other and leading to a sudden increase in the effects of the displaced
drug.
, 7. Question: What is the therapeutic index (TI), and why is it clinically important?
ANSWER ✓ The TI is the ratio between a drug's median lethal dose (LD50) and its
median effective dose (ED50). A high TI indicates a wide margin of safety, while a low TI
indicates a narrow margin, requiring close monitoring.
8. Question: What is an agonist versus an antagonist?
ANSWER ✓ An agonist binds to a receptor and activates it, mimicking the endogenous
regulatory molecule. An antagonist binds to a receptor but does not activate it, thereby
blocking the action of endogenous agonists.
9. Question: What is the primary enzyme system responsible for drug metabolism in
the liver?
ANSWER ✓ The Cytochrome P450 system.
Chapter 3: Adverse Drug Reactions & Medication Safety
10. Question: Differentiate between a side effect and an adverse effect.
ANSWER ✓ A side effect is a nearly unavoidable, secondary drug effect produced at
therapeutic doses. An adverse effect is any undesirable effect that occurs at standard
therapeutic doses and warrants a dose reduction, warning, or discontinuation.
11. Question: What is an idiosyncratic reaction?
ANSWER ✓ An unpredictable, abnormal drug response that is not dose-related and is
unique to an individual patient, often due to genetic differences.
Chapter 4: Drug Therapy in Special Populations: Pediatrics & Geriatrics
12. Question: Why are infants, especially neonates, at increased risk for adverse drug
reactions?
ANSWER ✓ Due to immature liver function (slower metabolism), immature kidney
function (slower excretion), and a more permeable blood-brain barrier.
13. Question: What are the key pharmacodynamic changes in older adults that affect
drug response?
ANSWER ✓ Increased sensitivity to many drugs, even at standard doses, due to changes
in receptor binding and post-receptor responses. For example, increased sensitivity to
CNS-acting drugs.
14. Question: What is the Beers Criteria?
ANSWER ✓ A list of medications that are potentially inappropriate for use in older
adults due to an increased risk of adverse events.
Chapter 5: Cholinergic & Anticholinergic Agents
15. Question: What are the classic symptoms of muscarinic poisoning (SLUDGE