Basic Kinetics I Flashcards
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
What are the parameter we are monitoring when looking at PK
- Drug concentration
- Time
What process will cause [Drug] to increase
Absorption
Which process will cause the [Drug] to decrease
- Distribution
- Metabolism
- Excretion
Cmax
maximum observed plasma drug concentration
Tmax
the time it takes to reach the maximum observed plasma concentration (Cmax)
MTC
Maximum Therapeutic Concentration
MEC
maximum effective concentration
Therapeutic Range/Window
MTC-MEC
What does blood consist of
WBC,RBC, Platelets, plasma proteins, small molecules, ions, water
Plasma
soluble component of blood, clotting factors are inactivated
Hematocrit
packed with RBC
Buffy Coat
WBC’s and Platelets
[Concentration]
= mass/volume
mass of drug=amt. of drug (mg)
[Concentration]=
= mass/volume
mass of drug=amt. of drug (mg)
What are the units for [Concentration]
mg/L
By what administration do we assume 100% absorption
IV
How many liters of blood does a human body have
5L
What is the volume of plasma in the human body
2.5 L
VD
volume of distribution
what is the equation for VD
Amt. of drug (mg)/[Concentration] (mg/L)
What is the unit for VD
Liters (L)
how much fluid is in the whole body
40 L
