Clinical Pharmacology and Therapeutics Flashcards
which three ways do drugs and the body interact
ion channels, enzymes, G proteins
what are the four main action of drugs working
activation or blocking receptors
activating or blocking enzyme function
opening or blocking ion channels
facilitation or blocking transport systems
what is affinity
how well the drug binds to a receptor
what is occupancy
how long the drug remains in the receptor
what is an agonist
chemical that when bound to a receptor causes expected change in receptor and body
what is a partial agonist
will bind to a receptor but not as good as making a response in the cell
what is an antagonist
will bind to receptor site but will not cause a conformational change the cell requires to have an action
give an example of a reversible agonist
atenolol which is a beta blocker
what is first pass metabolism
all blood from GI drains into hepatic portal vein which drains via liver - drug only reaches circulation after metabolism from liver
what is GTN
glyceryl trinitrate - used to treat angina and given sublingually
name five routes of drug administration
oral
intravenous
intramuscular
transdermal
subcutaneous
what is bioavailability
proportion of ingested drug that is available for clinical effect
give four ways bioavailability can be modified
dosage
route of administration
poor metabolism
what is the single compartment model
drug acts as it is evenly distributed through body
what is the two compartment model
drug behaves as if it is in equilibrium with different tissues
where can metabolism take place (2 places)
liver
plasma
what is involved in the first phase of metabolism
oxidation
reduction
hydrolysis
what is involved in phase two of metabolism
conjugation to a compound for excretion
what is the most common pathway in the body used for drug excretion
P450 mono-oxygenase system
what is the most extensive secretion pathway in the body
renal excretion of water soluble metabolites
what is first order kinetics
drug metabolism increases as drug concentration increases
what is zero order kinetics
drug metabolism at a fixed rate irrespective of drug concentration
what groups of people might have fewer plasma proteins therefore poorer drug distribution
very young
very old
name two barriers to drug distribution
blood-brain barrier
planta barrier
what is the cellular effect of penicillin
decreases permeability of bacterial cell wall
what type of microbes is metronidazole effective against
anaerobic
what is the cellular effect of metronidazole
inhibits DNA synthesis of bacteria
