Lecture 2: Pharmacokinetics Flashcards
What is pharmacokinetics?
Actions of body on the drug
What is pharmacodynamics?
Actions of drug on the body
What is the four basic pharmacokinetic processes?
1) Absorption
2) Distribution
3) Metabolism
4) Excretion
What is the normal way for drugs to enter the cell?
Simple diffusion
What is the normal way for drugs to exit the cell?
Active Transport System: P-glycoprotein
When can weak acids and weak bases cross membranes?
In their unionized forms
What formula is used to measure the amount of drug that is absorbed?
Salt x Bioavailability x Dose
How is bioavailability calculated?
F = [AUC oral]/[AUC IV}
What formula is used to measure the amount of drug that concentration ?
Cp = [Salt x Bioavailability x Dose]/[Vd]
How is volume of distribution calculated?
Vd = [Amount of drug in body]/[plasma concentration]
What factors affect drug distribution?
1) Ability of drugs to enter cells
2) Blood flow to tissues
A drug is only bioactive if it is what?
Free
What happens in Phase I of Drug Metabolism?
Biotransformation: make drugs more polar
- oxidation
- reduction
- hydrolysis
What happens in Phase II of Drug Metabolism?
Biotransformation: more water soluble and excretable
-conjugation
What enzyme family fosters drug metabolism?
Cytochrome P-450
Grapefruit juice is an ____ of the cytochrome P450.
Inhibitor
What does acetylation and methylation do to a drug?
Make it less water soluble and inactivates it
How are protein-bound drugs elminated?
Active tubular secretion
-Drug displace from protein binding sites near basolateral membranes of proximal tubule
How do you calculate the eGFR?
eGFR = [(140-age)(Body Weight)]/[72 x Scr]
