Basic Kinetics I Flashcards
(46 cards)
Pharmacodynamic
What the Drug does do the body
- Pharmacological effect
- Clinical Response
- Efficacy/Toxicity
Histamine H2 Receptor
A G-protein coupled receptor
GPCR
What is the GPCRs endogenous ligand
Histamine- which stimulates gastric acid production
What kind of protein is an H2 receptor
Transmembrane protein
Example of an H2 receptor antagonist
Famotidine- H2 receptor antagonist, used to treat GERD (blocks histamine from binding, hence less acid is produced)
Where is a GPCR present in the body
Mainly in the GI tract
stomach, small intestine
What kind of amino acids are likely in the transmembrane segments
Hydrophobic
What is a GABA receptor
a ligand-gated ion channel
Where is a GABA receptor found
Brain
What is the endogenous ligand for GABAa Receptor
GABA-which inhibits neurotransmission- rapid response time
example of a GABA receptor agonist
Zolpidem (Ambien)-binds to GABAa allosterically and helps GABA bind-
-used for insomnia
If affinity increases, what happens to KD
Decreases
Pharmacokinetics
what the BODY does to the drug
ADME
PK-ADME
Absorption- s.i.
Distribution-heart
Metabolism-liver
Excretion-kidney
KD
Dissociation Constant- concentration of free drug at which half of the receptors are bound
KD equation
KD= [D][R]/[DR]
What is the only parameter we have control over when we administer a drug
The concentration of the drug (dosing)
When drug concentration is increased, receptor binging is__________
increased
EC50
the drug concentration at which yields 50% maximal response
ED50
DOSE THAT IS THERAPEUTICALLY EFFECTIVE IN 50% OF THE POPULATION
TD50
The dose that causes toxic effects in 50% of the population
LD50
The dose that is lethal in 50% of the population (animal)
Therapeutic Index (TI)
the ratio between toxic dose and effective dose
Is it preferable to have a high or low TI
High
