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Fundamentals of Nursing | Nursing
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*[DOMAIN 1: PHARMACOKINETICS - 40 Questions]**
* *Question 1:** What is the primary definition of pharmacokinetics?
A) The study of what drugs do to the body
B) The study of what the body does to drugs **[CORRECT]**
C) The study of drug interactions at receptor sites
D) The study of drug manufacturing processes
* *Rationale:** Pharmacokinetics (ADME) refers to Absorption, Distribution, Metabolism, and
Excretion—what the body does to drugs. Pharmacodynamics (Option A) is what drugs do to the
body.
* *Question 2:** Which route of administration provides 100% bioavailability?
A) Oral
B) Intramuscular
C) Subcutaneous
D) Intravenous **[CORRECT]**
* *Rationale:** IV administration bypasses absorption barriers and first-pass metabolism,
delivering the entire dose directly into systemic circulation.
* *Question 3:** What is the first-pass effect?
A) The initial therapeutic response to a drug
B) Liver metabolism of oral drugs before they reach systemic circulation **[CORRECT]**
C) The first dose of a medication series
D) Rapid renal excretion of initial drug doses
,* *Rationale:** Oral drugs absorbed from the GI tract travel via hepatic portal circulation to the
liver, where significant metabolism occurs before the drug reaches systemic circulation,
reducing bioavailability.
* *Question 4:** Which factor does NOT affect drug absorption?
A) Route of administration
B) Blood flow to the absorption site
C) Drug solubility
D) Drug half-life **[CORRECT]**
* *Rationale:** Half-life is an elimination parameter (pharmacokinetic excretion phase), not an
absorption factor. Absorption depends on route, blood flow, solubility, pH, and surface area.
* *Question 5:** A patient receives oral morphine 30mg, but only 10mg reaches systemic
circulation. What is the bioavailability?
A) 10%
B) 33% **[CORRECT]**
C) 50%
D) 90%
* *Rationale:** Bioavailability = (Amount reaching circulation ÷ Dose administered) × 100 = (10 ÷
30) × 100 = 33%.
* *Question 6:** Which oral medication form generally has the fastest absorption?
A) Enteric-coated tablets
B) Sustained-release capsules
C) Solutions/Elixirs **[CORRECT]**
D) Film-coated tablets
* *Rationale:** Solutions are already in liquid form and don't require disintegration or dissolution,
allowing immediate absorption.
* *Question 7:** What does a high volume of distribution (Vd) indicate?
A) The drug remains primarily in the bloodstream
B) The drug distributes extensively into body tissues **[CORRECT]**
C) The drug has low lipid solubility
D) The drug is highly protein-bound
* *Rationale:** High Vd indicates extensive tissue distribution. Low Vd indicates the drug remains
in plasma. Vd = Total amount of drug in body ÷ Plasma drug concentration.
* *Question 8:** Which plasma protein binds the majority of circulating drugs?
A) Globulins
B) Fibrinogen
, ) Albumin **[CORRECT]**
C
D) Transferrin
* *Rationale:** Albumin is the primary drug-binding plasma protein. Only unbound (free) drug is
pharmacologically active and can be metabolized or excreted.
* *Question 9:** What percentage of drug is eliminated after 4 half-lives?
A) 75%
B) 87.5%
C) 93.75% **[CORRECT]**
D) 100%
* *Rationale:** After each half-life: 50% → 75% → 87.5% → 93.75% remains eliminated. It takes
4-5 half-lives to eliminate approximately 97% of a drug.
* *Question 10:** Which organ is primarily responsible for drug metabolism?
A) Kidneys
B) Liver **[CORRECT]**
C) Lungs
D) Intestines
* *Rationale:** The liver is the primary site of drug metabolism (biotransformation) through
various enzyme systems, most notably the cytochrome P-450 system.
* *Question 11:** What characterizes first-order elimination kinetics?
A) Constant amount eliminated per unit time
B) Constant fraction eliminated per unit time **[CORRECT]**
C) Zero drug elimination
D) Immediate complete elimination
* *Rationale:** First-order kinetics: a constant percentage (fraction) of drug is eliminated per unit
time. This is the most common elimination pattern.
* *Question 12:** Which drugs follow zero-order elimination kinetics?
A) Penicillin and cephalosporins
B) Alcohol and phenytoin **[CORRECT]**
C) Morphine and codeine
D) Aspirin and ibuprofen
* *Rationale:** Zero-order elimination involves constant amount (not fraction) eliminated per unit
time, occurring when metabolic enzymes are saturated. Examples include ethanol and
phenytoin at therapeutic concentrations.
**Question 13:** What is enzyme induction?
, ) Decreased drug metabolism
A
B) Increased drug metabolism affecting multiple drugs **[CORRECT]**
C) Inhibition of cytochrome P-450
D) Decreased protein binding
* *Rationale:** Enzyme induction occurs when one drug increases the activity of metabolic
enzymes (CYP450), increasing metabolism of itself and other drugs. Examples: rifampin,
carbamazepine, phenytoin, phenobarbital, St. John's wort.
* *Question 14:** Which substance inhibits CYP3A4 enzymes?
A) Rifampin
B) Carbamazepine
C) Grapefruit juice **[CORRECT]**
D) Phenobarbital
* *Rationale:** Grapefruit juice contains furanocoumarins that inhibit CYP3A4, increasing levels
of drugs metabolized by this enzyme (statins, calcium channel blockers, immunosuppressants).
* *Question 15:** What is the best clinical estimate of renal function for drug dosing?
A) Blood urea nitrogen (BUN)
B) Serum creatinine alone
C) Creatinine clearance (CrCl) **[CORRECT]**
D) Urine specific gravity
* *Rationale:** Creatinine clearance (calculated using Cockcroft-Gault equation or measured) is
the best estimate of glomerular filtration rate and renal drug elimination capacity.
* *Question 16:** Which drug class requires dose adjustment in renal impairment?
A) Penicillins
B) Aminoglycosides **[CORRECT]**
C) Macrolides
D) Azole antifungals
* *Rationale:** Aminoglycosides (gentamicin, tobramycin, amikacin) are nephrotoxic and renally
eliminated, requiring careful monitoring of renal function and dose adjustment.
* *Question 17:** How does increased gastric pH affect drug absorption?
A) Increases absorption of all drugs
B) Decreases absorption of acid-labile drugs
C) Increases absorption of basic drugs **[CORRECT]**
D) Has no effect on drug absorption