Unit 2 Flashcards
pharmacokinetics
study of how a drug moves into, through, and out of the body
pharmacodynamics
how the drug actually produces its affect on the body
therapeutic range, therapeutic window
ideal range of concentrations within the body
what should administering manufacturer’s approved drug dose achieve?
plasma (serum) concentrations within the therapeutic range
Top end of normal therapeutic range that represents border between those concentrations that are beneficial and those concentrations at which signs of toxicity develop
maximum effective concentration
Bottom end of normal therapeutic range
minimum effective concentration
The blood or plasma concentrations of drug below the minimum effective concentration the drug will not achieve the drug’s beneficial effect
subtherapeutic
primary organs involved in removing drugs from body (organs of elimination)
liver and kidneys
3 components of therapeutic administration of drugs or dosage regimen
dose, dosage interval, and route of administration
amount of drug administered at one time to a particular patient
dose
loading dose
larger than maintenance dose and is designed to raise drug concentration to therapeutic range in short time
dosage interval
time between administration of separate drug doses
total daily dose
combined amount of drug (mass) administered in a given day
route of administration
means by which drug is given
drugs given by injection
parenterally administered
IV bolus
intravenous injections given as a single, large volume at one time
IV infusion
slowly injected or “dripped” into a vein
constant rate IV infusion
results in steady accumulation of drug concentrations in the body until they reach a plateau or steady state, and remain there until infusion is stopped
accidental injection of IV administered drug outside of the blood vessel
extravascular or perivascular injection
intraarterial injection
injected into the artery towards a specific tissue or organ
steady state
point at which drug administered by CRI reaches a concentration plateau
CRI
constant rate infusion
extravascular
injection of an IV drug into the tissue outside of the vein is said to have been given this way
SQ
injecting a drug under the skin
intradermal
injecting a drug into the layers of the skin
intraperitoneal
injecting a drug into the abdominal body cavity
per os
drugs given by mouth
topically administered
route of administration by which drugs are applied to the surface of the skin
aerosol administration
administration of a drug as an inhaled mist or gas
passive diffusion
movement of a drug through a membrane that does not require a carrier molecule or cellular energy to move the drug molecule
facilitated diffusion
movement of a drug across a membrane carried by a carrier but doesn’t require cellular energy to move the molecule across the membrane
active transport
movement of a drug molecule across a cell membrane by use of a carrier molecule and cellular energy to pump the drug molecule across the membrane
concentration gradient
the range of the drug molecule concentrations from high concentration to low concentration
equilibrium
point at which the number of molecules at two different points are the same, or the number of molecules entering and leaving an area are equal
pinocytosis, phagocytosis
process by which cells ingest a drug molecule
lipophilic
fat loving
hydrophilic
water loving
aqueous medium
water-based liquid into which some drugs can be dissolved
absorption, distribution, metabolism, excretion
4 steps of pharmacokenitics
absorption
movement of drug molecules from the site of administration to systemic circulation
bioavailability
percentage of drug administered that actually makes it into the blood stream and be absorbed
extracellular
fluid outside of the cells
base
type of drug that acquires H+ ions and becomes ionized
acid
type of drug that acquires H+ ions and becomes non-ionized
pKa
the pH at which a drug exists in a balanced 1:1 ratio of ionized to non-ionized molecules
ion trapping
phenomenon where a drug molecule exists in a lipophilic form passes through a cell membrane into another compartment with a different pH, resulting in the drug molecules becoming more ionized and not being able to diffuse through the cell membrane to leave the compartment
dissolution
step in which a solid dosage form breaks down into very small particles capable of being absorbed across the GI tract wall
hepatic portal system
system of blood vessels that conducts blood from the intestine to the liver before the blood passes into systemic circulation
first-pass effect
phenomenon in which a drug absorbed from the GI tract is mostly removed by the liver and excreted before the drug reaches systemic circulation
xenobiotics
any “foreign substance” from outside of the body
perfusion
the degree to which a tissue is supplied with blood
distribution
pharmacokinteic process in which the drug moves from the systemic circulation to the tissues
fenestrations
small openings in the capillaries through which small drug molecules can pass
redistribution
movement of drug from a tissue back into the blood and then to a second tissue
hypoproteinemia
condition when there is low protein in the blood
volume of distribution
pharmacokinetic parameter that gives an approximation of the extent to which a drug is distributed
receptor
term that describes the specific protein into which a drug interacts to produce a cellular effect
affinity
the “fit” between the drug molecule and the receptor
intrinsic activity
the characteristic of a drug that means when the drug combines with a receptor, it produces a cellular effect
agonist
type of drug that combines with a receptor and has intrinsic activity
antagonist
type of drug that combines with a receptor and has no intrinsic activity
competitive antagonism, reversible antagonism, surmountable antagonism
relationship between two drugs that can combine with the same receptor and whose effect on the cell is determined primarily by which of the two drugs is present at the greater concentrations
noncompetitive antagonism
relationship between two drugs that can combine with the same receptor and whose effect on the cell is determined primarily by which drug has a greater “advantage” that prevents the other drug from combining with the receptor
partial antagonist
drug that has weak intrinsic activity, but is capable of reducing effect of another competitive drug
nonreceptor-mediated drug reaction
drug effects that are not caused by linking of a drug to a receptor
biotransformation, drug metabolism
pharmacokinetic process in which a drug is chemically altered by the liver or other tissues
metabolite
product of biotransformation
conjugation
metabolic process in which two molecules are combined together or produce a new molecule
metabolic induction
the rate of metabolism of drugs, especially drugs metabolized by the MFO system, is increased
renal elimination
excretion of a drug by the kidney
hepatic elimination
excretion of a drug by the liver
filtration
process of renal elimination in which the drug is passively pushed from the glomerulus into the Bowman’s capsule
proximal convoluted tubule
part of the kidney nephron in which active transport mechanisms move electrolytes, glucose, and some drug molecules out of the urine and back into the body
active secretion
process by which the proximal convoluted tubule actively pumps drugs into the urine
reabsorption
movement of molecules back into the body from urine in the loop of Henle
enterohepatic circulation
process in which a hepatically excreted drug is reabsorbed from the GI tract and re-enters systemic circulation only to be excreted again, reabsorbed again, and again
clearance
speed at which a volume of blood is “cleaned” of all drug
half-life emilination
time it takes for the concentration of the drug in the blood to drop by half
steady state
point after a drug has either been given multiple times where the peak concentrations all become the same and the trough concentrations all become the same
withdrawal time
time after drug administration during which the animal receiving the drug cannot be sent to market for slaughter nor the eggs or milk from that animal be used for human food
