Pharm Terminology Flashcards
What is the lock and key model of drug action?
We have variety of cell receptors in our cells. Drug get out of leaky blood vessel and target the receptors on the cell surfaces. This then causes inner cell signaling.
*Key word is : “leaky” blood vessels. In inflammation blood vessels become dilated and this makes the drug more likely to accumulate/target the specific tissue.
Define drug Affinity.
Potential for drug-receptor binding.
It is how much affinity the drug has for the receptor. So a drug with a high affinity will find the receptor. A drug with low affinity will have trouble finding the receptor and when it does it may not be very long before it falls off the receptor because of the weak integration.
Define Intrinsic activity.
This is the capacity of the drug to produce a biological effect. (Here biological effect means therapeutic effect).
Define Agonist.
SUBSTANCES that stimulate a receptor to produce a physiological reaction.
Agonist have intrinsic activity (aka beneficial biological effect) and affinity.
Define Antagonists
SUBSTANCES that oppose or interfere with the activity of a receptor and its endogenous substrate without producing a physiologic effect itself;
antagonists have affinity but LACK intrinsic activity.
Allostery
A stereospecific phenomenon whereby a bound ligand influences specificity of a second site.
*in allostery, the configuration of the protein/enzyme is changed.
Define Efficacy
Efficacy = [affinity] X [intrinsic activity]
-How well the drug finds its receptor and cause a biological effect.
Efficacy of a drug is dose INdependent. Unlike potency that is dose dependent.
*so the greater the affinity the drug has the greater the efficacy of the drug.
Thus the efficacy is zero for antagonists.
What is the difference between EC50 and ED50
EC50: this is the effective [concentration] in 50% of patients.
ED50: is the effective DOSE in 50% of patients.
**concentration is a laboratory measurement, dose is a clinical measurement. So we care more about EC50.
What is IC50?
IC50: This is the ‘inhibitory’ concentration in 50% of subjects.
*the term inhibition tells us that we are talking about antagonist.
Describe hypersensitivity in the context of pharmacology.
Hypersensitivity is the result of repeated or chronic antagonism.
*If you are exposed to something repeatedly, your body can become hypersensitive. So this is explaining a heightened sensitivity that some tissues can produce.
Example: in anisocoria, hypersensitivity allows us to diagnose which nerve it causing it?
What is maximum dose of a drug?
It is the MINIMUM amount of drug that produces the maximum therapeutic effect.
What is the difference between pharmacodynamics and pharmacokinetics?
Pharmacodynamics: Drug → Body *what the drug does to the body.
Pharmacokinetics: Body → Drug (ADME) *what the body does to the drug.
What is Partial agonist?
Low intrinsic activity with potency and affinity within therapeutic range.
*low potential to produce intrinsic activity (biological effect) with potency. but it has an affinity within a therapeutic range.
True or False: Potency is inversely related to both EC50 and IC50.
True.
- the lower the EC50 the higher the potency of the drug.
- the lower the IC50 the higher the potency.
What is Pharmacotherapeutics?
Pharmacotherapeutics: The study of the therapeutic uses and effects of drugs on diseases.
