Drug Toxicity Flashcards
ED50, TD50, and LD50 all occur in what type of subjects?
live subjects
What is the median effective dose, dose that produces a response in 50% of the population, produces 50% of maximal effect?
ED50
What is the dose required to produce a toxic effect in 50% of the population?
TD50
What is the dose required to kill 50% of the population (animals)?
LD50
What measures drug safety and can be found by TD50/ED50 or LD50/ED50?
therapeutic index (TI)
What does a high TI mean?
safer drug
If TI is 4, what does that mean?
only takes 4x the regular dose to produce a toxic/lethal response
What is the minimum effective dose to minimum toxic dose; doses in this range are effective and essentially free of side effects?
therapeutic window
What is the range from where a drug begins to work to when adverse effects begin but has some overlapping?
therapeutic window
What describes proteins or glycoproteins on surface of a cell, on an organelle, or in the cytoplasm designed to bind to endogenous substances?
drug receptors
When a drug or endogenous ligand reaches a receptor, what changes can occur?
- opening/closing of ion channel
- formation of biochemical messengers
- inhibition of normal cellular functions
- increase in cellular activity
There are only so many receptors in the body, so what can occur?
saturation (can lead to no more effect of drug on patient)
Drugs may be what for receptors?
selective (only binding to certain receptors) or non-selective (binds to everything)
If a drug binds to somewhere other than its intended site, what happens?
it is ineffective, no use
Unbound drug concentrations are important why?
this is the portion of drug free to interact with its target site
Drugs do not add what when interacting with the receptor?
a new function
NEVER a new function
- can be turned on, turned off, or attentuated
What are active receptors that possess affinity and activity (potent and effective)?
agonist
What creates a similar response to your biological function?
agonists
What are the different type of agonists?
- full agonists
- partial agonists
- inverse agonists
What type of agonists produce a max response and show full efficacy?
full agonists
What type of agonists never reach Emax so they have some efficacy but not full?
partial agonists
What type of agonist produce an effect opposite that of the natural ligand (basil function that is shut off and not producing)?
inverse agonist
What binds to receptors to block the binding of other substances?
antagonist
What prevents an action from occurring?
antagonist
What must be present or else an antagonist is not active and producing a neutral effect?
agonist
What possessed affinity (potency) but not activity (efficacy)?
antagonists
What type of antagonists compete for the same binding site as the agonist and is a reversible process?
competitive antagonist
With competitive antagonists, the dose-response curve shifts?
right (becomes less potent, EC 50 changes)
What can you add to a system to overcome a competitive antagonist?
add more agonist
What type of antagonist binds to the same site as an agonist using covalent bonding so it is permanent and irreversible?
noncompetitive antagonists
What reduces the effect of an agonist since there is a reduction in the amount of sites that agonists can bind to?
noncompetitive antagonists
What describes binding to a site other than the agonist binding site resulting in a conformational change and what is this associated with?
- allosteric
- noncompetitive antagonists
How can you overcome noncompetitive antagonists?
add more binding sites, not more agonists
What acts as competitive antagonists in the presence of an agonist?
weak partial agonist
Weak partial agonists have some activity (efficacy) but it is opposite of what?
agonists
When you add weak partial agonists, it will be harder for what to bind so you will get a decrease in?
harder for agonists to bind so you will get a decrease in efficacy
