Questions and Answers
Pharmacology - Correct answer-the study of drugs and their structure, targets of
action, mechanisms of action (MOA), distribution (how the body disburses them
throughout the body), desired physiologic effects (efficacy) and undesirable side
effects (toxicity).
Pharmacokinetics - Correct answer-(absorption, distribution, metabolism and
elimination
Absorption - Correct answer-absorption from the administration site either directly
or indirectly into the blood/plasma.
Distribution - Correct answer-reversibly/irreversibly movement of drug from the
bloodstream into the interstitial and intracellular fluid.
Metabolism - Correct answer-drug biotransformation via metabolic pathways,
primarily the liver, or by other tissues.
Elimination - Correct answer-how parent drug & its metabolites are eliminated
from the body
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,Factors affecting absorption - Correct answer-· Gastrointestinal pH changes
· Gastric emptying
· Gastric/intestinal enzymes
· Bile acids & biliary function
· Gastrointestinal flora (type and quantity of bacteria)
· Food & nutrient interactions (most common interaction influencing GI drug
absorption)
· Lipid solubility of the drug
Factors affecting distribution - Correct answer-· Membrane permeability: Cross
membranes to site of action
· Blood brain barrier reduces the speed of drug passage into and out of brain tissue
· Plasma protein binding: drugs bound to plasma proteins do not cross membranes
(Note: Malnutrition = âalbumin = á free drug = greater pharmacologic response)
· Aging cause a reduction in production of plasma proteins
· Lipophilicity of drug: lipophilic drugs concentrate in adipose tissue; remain in the
body for a longer period of time
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, Factors affecting metabolism - Correct answer-o Drugs can undergo metabolism in
the lungs, blood, liver, intestines and kidney
o Volatile drugs are primarily excreted by the lungs
· The body changes drugs to more or less active forms (metabolites), increases
water solubility to increase elimination.
Factors affecting excretion - Correct answer-Elimination of drugs most often
involves renal function (renal blood flow, creatinine clearance [CrCl]).
· Linear = Rate of elimination is proportional to amount of drug present.
· Dosage increases result in proportional increase in plasma drug levels.
· Unbinding of nonvolatile drugs from plasma protein binding sites
· Volatile drugs are excreted by the lungs
Half-life - Correct answer-· The time required for serum plasma concentrations to
decrease by one-half (50%).
· Determines how frequently the drug must be administered
· Predicts how long toxic effects can last (when the drug is over the minimum toxic
level)
· Half-life is constant with first-order pharmacokinetics of a drug
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