Exam 1 Flashcards
psychopharmacology
study of the effects of substances of affect, cognition, and behavior
substance
medication to treat a disease
chemical likely to be abused
exogenous chemical that significantly alters the function of certain bodily cells when taken in relatively low doses (chemical not required for normal cellular functioning)
ligands that act on receptors to exert their effects
neuropharmacology
study of substance-induced brain changes at the physiological, receptor, biochemical, and molecular levels
pharmacokinetics (+ acronym)
body’s effect on the actions of substance
Absorption, Distribution, Metabolism, Excretion
pharmacodynamics
substance’s effect on bodies
physiological factors affecting substance action
dose and chemical structure of substance
bioavailability (amount of the substance in the blood that is free to bind at a target site)
absorption
compound’s ability to pass through barriers
distribution
how the compound is distributed around the body and its propensity to accumulate in certain tissues or organs
metabolism/biotransformation
how the body breaks down the compounds
excretion
rate and process through which the compound exits the body
effect of route of administration
blood level of same amount of substance varies with route of administration
factors affecting absorption
membrane structure
lipid-soluble substances
ionized substances
pH
pKa
how does membrane structure affect absorption
physical characteristics of cell membrane play huge role in substance action
phospholipids arranged in bilayer (polar heads towards water, nonpolar tails away from water)
**polar = hydrophilic
how do lipid soluble substances affect absorption?
can pass through membrane via passive diffusion, dependent on their concentration gradient
lipid soluble substances = non polar / hydrophobic ; they can pass through phospholipid bilayer
how do ionized substances affect absorption?
most substances are not lipid soluble (weak acids or bases and are polar)
ionization (dissociation of a molecule into charged ions ; pH and pKa)
how does pH affect absorption?
substances are differently soluble in different pH, dependent on the molecular structure of the substance
pH can damage or destroy certain substances, rendering them inactive or inert
how does pKa affect absorption?
pKa (pH of the aqueous solution at which 50% of the substance would be ionized)
substances that are weak acids ionize better in alkaline solution, and substances that are weak bases ionize better in acidic solution (substances with basic pH ionize better in acidic pH)
blood brain barrier
selectively permeable to ionized compounds but fully permeable to lipid-soluble compounds
first-order kinetics
biotransformation occurs at exponential rate (50% of substance removed at each time interval - half life - t(1/2) )
zero-order kinetics
biotransformation at constant rate
type 1 biotransformation
nonsynthetic
oxidation, reduction, hydrolysis
type 2 biotransformation
synthetic
combine substance with other molecules (glucoranide, sulfate, methyl groups)
enzyme induction
increase in liver enzymes
substances used repeatedly so metabolism increases
enzyme inhibition
less enzymes, less metabolism
more intense, prolonged effect
up regulation of receptors
of receptors increase due to absence of substance
down regulation of receptors
of receptors decrease due to abundance of substance
what causes a drug action/effect?
agonist + receptor interaction
dose response curves
compare amount of biological response for a given dosage
ED(50) (dose that produces half the maximal effect)
TD(50) (dose at which 50% of people suffer a toxic effect)
TI (therapeutic index; TD(50)/ED(50))
potency
absolute amount of substance needed to produce a specific effect
orthosteric site
site where natural endogenous ligand binds
site where an exogenous full agonist binds
allosteric site
site that is not sufficient to activate the receptor when bound
acute tolerance
rapid tolerance after one use of substance
substance disposition tolerance / metabolic tolerance
repeated use of substance decreases amount of substance that reaches target tissue (enzyme induction)
pharmacodynamic tolerance
changes in neuronal function compensate for continued presence of the substance (receptor regulation)
behavioral tolerance
when tolerance is shown in an environment where substance is repeatedly used but not in a novel environmentq
sensitization
reverse tolerance
enhancement of substance effects following repeated use of same substance
