pharmocolgy 1 Flashcards
pharmodynamics
- study of the biochemical and physiological effects of drugs and their mechanisms of action
pharmokinetics
- absorption, distribution, biotransformation and excretion of drugs
toxicology
- adverse effects of drugs and chemicals
pharmotherapeutics
- use of drugs in the prevention and treatment of disease
what is a drug
Chemical substance of known structure which when given to a living organisms produces a biological effect
selectivity
- one effect predominates over a particular dose range (therapeutic window)
- within this range the drug may be termed selective
general mechanisms of drug activity eg deficiency
deficiency - replacement therapy
excess action - chemical antagonist can reduce or block the effect of an excess activity of normal processes
physiochemical environment
- drugs can alter the environment or characteristics of cell/tissue
types of effects of drugs
1) Therapeutic effects
- the desired or anticipated effect
2) Side effects
- other than therapeutic effects occurring at therapeutic doses
3) Toxic or adverse effect
- deleterious effects usually occurring at higher doses
4) Lethal effect
- death caused by very high drug dose
acceptors
- substances drugs bind to without causing any effect (eg plasma proteins)
receptors
cell component directly involved in reaction of some drugs and initiate the chain events leading to drug observed effect
drugs can either be
1) agonist
- initiates a response
- many endogenous agonist (eg neurotransmitters and hormones)
2) antagonist
- does not initiate a response, prevent agonist binding
receptor locations
cell membrane
nucleus
cytoplasm
biological targets for drugs
receptor
ion cennels
enzymes
transporters
classes of cell surface receptors
ion channel linked receptor
G protein linked receptor
enzyme linked receptro
ion channel linked receptor
- part of the structure the ligand binds to,
- changes opening and closing of the ion channel
- can modulate the amount of ions entering the cell
G protein linked receptor
- transmembrane receptor
- G protein found intracellularly
- Once ligand binds on the extracellular site, G protien activated and can lead to activation of a cascade of events leading to physiological change
Enzyme linked receptor
- has a binding site for ligand
- once bound, change in intracellular site by activating catalytic domain
efficacy
- relationship between receptor occupancy and ability to initiate a response at molecular, tissue or cellular level
affinity
- ability to bind to a receptor
potency
- how much drug is required to produce a particular effect
- depends on both affinity and efficacy
full vs partial agonist
- based on the maximal pharmacological response that occurs when all the receptors are occupied
antagonist
- binds but does not activate and are used to prevent agonist from binding
- allows us to increase the dose, causes a right shift
anti inflammatory action of steroids
bind to receptor
bind to nucleus
act on phsopholipases
required for arachnid pathway involved in inflammation
glucocorticoids effects and what they act on
Act on intracellular receptors
1) Vascular events
- reduce vasodilation
- decrease fluid exudation
2) inflammatory and immune mediators
- reduces production and action of cytokines
3) cellular population
- reduces clonal expansion of T/B cells
- decreases action of cytokine secreting T cells
what do NSAIDS do
unlock cox 1 and 2
inhibit enzymatic activty
what do benzodiasepies/barbiturates do
Act on ion channels and chloride channels
- Acid binds on the extraceullar side (GABA side)
- modulate how much chloride can enter the channel (- change) can induce hyperpolarization
successful therapy depends on
host defence mechanisms
location of infection
pharmokinetics
dynamic properties of antibacterial
what do beta lacatam antibiotics do
disrupt the synthesis of peptidoglycan layer of bacterial cell walls
