NURS 635 Midterm
Pharmacology - 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 - answer(absorption, distribution, metabolism and elimination
Absorption - answer absorption from the administration site either directly or indirectly
into the blood/plasma.
Distribution - answer reversibly/irreversibly movement of drug from the bloodstream into
the interstitial and intracellular fluid.
Metabolism - answerdrug biotransformation via metabolic pathways, primarily the liver,
or by other tissues.
Elimination - answerhow parent drug & its metabolites are eliminated from the body
Factors affecting absorption - 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 - 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
Factors affecting metabolism - answero 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 - answerElimination 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 - 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
· Zero-order (nonlinear) pharmacokinetics means a drug is metabolized at a constant
rate per unit time.
Steady state - answerusually reached within 4-5 half-lives of a drug
Michaelis-Menten pharmacokinetics - answerthe rate of drug elimination is directly
proportional to the concentration of free drug. (e.g., phenytoin)
Narrow therapeutic index (NTI) - answerwhen the difference between an effective dose
and a toxic blood level is small.
Wide therapeutic index - answerA drug is safer and requires less intense monitoring.
Drug potency - answerThe concentration needed to produce a measurable effect.
Bioequivalence - answerTwo drugs have comparable bioavailability.
Margin of Safety - answerspace between the therapeutic and lethal doses of a drug
Loading doses - answer· allow rapid achievement of therapeutic serum levels.
· Loading doses are the same for patients regardless of their metabolism/elimination
dysfunction.
Affinity - answero Refers to the strength of binding between a drug and receptor.
o Number of occupied receptors is a function of a balance between bound and free
drug.
Dissociation constant (KD) - answero Measure of a drug's affinity for a given receptor.
o Defined as the concentration of drug required in solution to achieve 50% occupancy of
its receptors.
Therapeutic Index (TI) - answero Measure of the safety of a drug
o Calculation: LD50/ED50
Pharmacology - 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 - answer(absorption, distribution, metabolism and elimination
Absorption - answer absorption from the administration site either directly or indirectly
into the blood/plasma.
Distribution - answer reversibly/irreversibly movement of drug from the bloodstream into
the interstitial and intracellular fluid.
Metabolism - answerdrug biotransformation via metabolic pathways, primarily the liver,
or by other tissues.
Elimination - answerhow parent drug & its metabolites are eliminated from the body
Factors affecting absorption - 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 - 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
Factors affecting metabolism - answero 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 - answerElimination 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 - 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
· Zero-order (nonlinear) pharmacokinetics means a drug is metabolized at a constant
rate per unit time.
Steady state - answerusually reached within 4-5 half-lives of a drug
Michaelis-Menten pharmacokinetics - answerthe rate of drug elimination is directly
proportional to the concentration of free drug. (e.g., phenytoin)
Narrow therapeutic index (NTI) - answerwhen the difference between an effective dose
and a toxic blood level is small.
Wide therapeutic index - answerA drug is safer and requires less intense monitoring.
Drug potency - answerThe concentration needed to produce a measurable effect.
Bioequivalence - answerTwo drugs have comparable bioavailability.
Margin of Safety - answerspace between the therapeutic and lethal doses of a drug
Loading doses - answer· allow rapid achievement of therapeutic serum levels.
· Loading doses are the same for patients regardless of their metabolism/elimination
dysfunction.
Affinity - answero Refers to the strength of binding between a drug and receptor.
o Number of occupied receptors is a function of a balance between bound and free
drug.
Dissociation constant (KD) - answero Measure of a drug's affinity for a given receptor.
o Defined as the concentration of drug required in solution to achieve 50% occupancy of
its receptors.
Therapeutic Index (TI) - answero Measure of the safety of a drug
o Calculation: LD50/ED50
