PHARMACOLOGY PRINCIPLES FOR
NURSING AND PRESCRIBING
NEWEST 2025 & 2026 COMPLETE
QUESTIONS AND CORRECT
DETAILED ANSWERS
Pharmacodynamics - answerWhat the drug does to the body
Agonist - answerBinds and activates the receptor, mimicking an endogenous substance
Partial agonist - answerBinds and activates the receptor but produces a smaller
maximal response than a full agonist
Antagonist - answerBinds but does not activate the receptor; blocks other
chemicals/drugs from binding
Minimum effective concentration (MEC) - answerLevel below which therapeutic effects
will not occur
Minimum toxic concentration (MTC) - answerLevel above which toxic effects begin
Therapeutic index/range - answerMTC − MEC. High therapeutic index = wide safety
margin; low therapeutic index = narrow margin requiring close monitoring
Bioavailability - answer% of administered drug that reaches systemic circulation
unchanged
Serum half-life - answerTime for blood drug level to fall by 50%; determined by
metabolism/excretion, not dose
Steady state - answerTakes ~4-5 half-lives to reach steady-state blood levels and ~4-5
half-lives to fully eliminate a drug
Absorption - answerMovement of drug from administration site into the blood
Distribution - answerMovement of absorbed drug through body fluids to target tissues
Metabolism (Biotransformation) - answerEnzymatic alteration of drug structure —
mostly hepatic
Excretion (Elimination) - answerRemoval of drug from the body
, Protein Binding - answerDrugs circulate in bound (inactive) and free/unbound (active)
states
Prodrugs - answerAdministered in an inactive form and metabolized into the active
compound
First-Pass Effect - answerOral drugs travel through the portal circulation to the liver
before reaching systemic circulation
CYP450 - answerMost Phase I hepatic metabolism occurs via the cytochrome P450
microsomal enzyme system
Additive effect - answerTwo drugs with similar mechanisms sum their effects (1+1=2)
Synergism - answerTwo drugs with different mechanisms produce a greater-than-
additive effect (1+1=3)
Interference - answerOne drug accelerates or slows metabolism/excretion of another
Displacement - answerTwo drugs compete for the same protein-binding sites
Antagonism - answerEffects of two drugs cancel each other out
Incompatibility - answerPhysical interaction between two drugs interferes with the effect
of at least one
Drug-Food Interactions - answerInteractions between drugs and food that affect drug
absorption or efficacy
Rational Drug Selection - answerThe process of choosing the appropriate drug for a
patient
Federal Food and Drug Act (1906) - answerResponse to children dying from tainted
food products
Harris-Kefauver Amendment (1962) - answerMandated preclinical animal trials before
testing drugs in children
Off-label prescribing - answerUsing a drug for a non-FDA-labeled indication, based on
rational scientific principles
Controlled Substances Schedule I - answerNo accepted medical use; no legal use
except registered research
NURSING AND PRESCRIBING
NEWEST 2025 & 2026 COMPLETE
QUESTIONS AND CORRECT
DETAILED ANSWERS
Pharmacodynamics - answerWhat the drug does to the body
Agonist - answerBinds and activates the receptor, mimicking an endogenous substance
Partial agonist - answerBinds and activates the receptor but produces a smaller
maximal response than a full agonist
Antagonist - answerBinds but does not activate the receptor; blocks other
chemicals/drugs from binding
Minimum effective concentration (MEC) - answerLevel below which therapeutic effects
will not occur
Minimum toxic concentration (MTC) - answerLevel above which toxic effects begin
Therapeutic index/range - answerMTC − MEC. High therapeutic index = wide safety
margin; low therapeutic index = narrow margin requiring close monitoring
Bioavailability - answer% of administered drug that reaches systemic circulation
unchanged
Serum half-life - answerTime for blood drug level to fall by 50%; determined by
metabolism/excretion, not dose
Steady state - answerTakes ~4-5 half-lives to reach steady-state blood levels and ~4-5
half-lives to fully eliminate a drug
Absorption - answerMovement of drug from administration site into the blood
Distribution - answerMovement of absorbed drug through body fluids to target tissues
Metabolism (Biotransformation) - answerEnzymatic alteration of drug structure —
mostly hepatic
Excretion (Elimination) - answerRemoval of drug from the body
, Protein Binding - answerDrugs circulate in bound (inactive) and free/unbound (active)
states
Prodrugs - answerAdministered in an inactive form and metabolized into the active
compound
First-Pass Effect - answerOral drugs travel through the portal circulation to the liver
before reaching systemic circulation
CYP450 - answerMost Phase I hepatic metabolism occurs via the cytochrome P450
microsomal enzyme system
Additive effect - answerTwo drugs with similar mechanisms sum their effects (1+1=2)
Synergism - answerTwo drugs with different mechanisms produce a greater-than-
additive effect (1+1=3)
Interference - answerOne drug accelerates or slows metabolism/excretion of another
Displacement - answerTwo drugs compete for the same protein-binding sites
Antagonism - answerEffects of two drugs cancel each other out
Incompatibility - answerPhysical interaction between two drugs interferes with the effect
of at least one
Drug-Food Interactions - answerInteractions between drugs and food that affect drug
absorption or efficacy
Rational Drug Selection - answerThe process of choosing the appropriate drug for a
patient
Federal Food and Drug Act (1906) - answerResponse to children dying from tainted
food products
Harris-Kefauver Amendment (1962) - answerMandated preclinical animal trials before
testing drugs in children
Off-label prescribing - answerUsing a drug for a non-FDA-labeled indication, based on
rational scientific principles
Controlled Substances Schedule I - answerNo accepted medical use; no legal use
except registered research
