Pharmocology Flashcards
what is a drug?
a single chemical substance, that can be one of the constituents of a medicine - producing a physiological affect
what is a medicine?
a chemical preparation that contains one or more active constituents (drugs) together with additives with the intent of eliciting a therapeutic effect
what is physiological communication?
signals that get a response from the body
what is pharmacodynamics?
what the drug does to the body
what is a voltage sensitive (gated ion channel)?
the impulse arrives and open the channel to allow the ions to pass through (requires the impulse to open the gate)
what is a receptor?
a specific protein capable of binding to a specific group of drugs or endogenous substances
what is a ligand?
a substance that binds to a receptor
may normally be found in the body (endogenous) or may enter the body from outside (exogenous)
what does the term endogenous mean?
in the body
what does the term exogenous mean?
enters the body from outside
explain a ligand gated ion channel
the ligand binds to its binding site which opens up the the gate/channel allows the ion to move through (no impulse needed)
explain high and low affinity
receptors bind to substances by weak bond. (+ to - and - to +).
explain the two different types of antagonists
competitive and non-competitive
competitive - competes against agonist for the same binding site
non-competitive - binds to another site than the binding site
what are the two different types of agonists??
full and partial
full - produce a maximal response
partial - produce a sub-maximal response
what is an agonist?
drugs with high affinity and high intrinsic activity. stimulate an action in the body
what is an antagonist?
drugs with high affinity but no intrinsic activity (blocks the action in the body)
name the two internal (via gut) routes of drug administration
oral and rectal
name some parental (avoid the gut) routes of drug administration
buccal, sublingual, transdermal, intramuscular/subcut injections, epidural
what is pharmacokinetics?
what the body does to the drug
what is the therapeutic index?
balance of the benefits and the risks.
a measure of the margin of safety of a drug
relationship between a drugs therapeutic and toxic affect
name the four stages of drug disposition
absorption > distribution > metabolism > excretion (ADME)
explain absorption (ADME)
lipid soluble compounds can traverse across a membrane, but water soluble compounds cannot (they require a ion transport protein - for help across)
explain distribution (ADME)
the amount of drug in body tissues, fluid or spaces.
movement of a drug between the blood pas lama and tissues, occurs until eh drug reaches equilibrium
explain metabolism (ADME)
drugs may undergo: phase 1 alone, or phase 2 alone. aim is to make the drug water soluble
explain excretion (ADME)
drugs are eliminated from the plasma in 3 ways:
redistribution
liver metabolism
renal excretion
e.g bile from the liver, in urine from the kidneys or via the lungs, saliva or hair
