Session 1 - Pharmacokinetics Flashcards
What does ADME stand for?
Absorption
Distribution
Metabolism
Elimination
What are two potential routes drugs can be administered?
Oral and parenteral
What is oral administration?
Enter via GI tract, sublingual or rectal
What is parenteral admin?
Any route that doesn’t involve GI tract
What are two overarching factors which effect peak plasma concentration of a drug?
Rate of uptake of a drug and first pass metabolism
Give four factors which can effect systemic entry of a drug
Gastrointenstinal motility, splanchnic blood flow, molecular size, pH levels
What is first pass metabolism?
Any metabolism drug undergoes before reaching systemic circulation. This occurs via liver, gut lumen or gut wall.
How can the gut lumen effect drugs?
Gastric acid or proteolytic enzymes
How can gut wall effect drugs?
Glycoprotein efflux pumps drugs out of intenstinal enterocyte back into the lumen
What is bioavailability?
The amount of drug which reaches the systemic circulation in an unchanged form relative to that if administered via IV.
How is bioavailability calculated?
Amount of drug reaching systemic circulation/total amount of drug adminstered
What is the difference between oral bioavailability and bioavailability?
Oral bioavailability is normally synonymous with bioavailability, yet specifically refers to when drug is administered orally. It can be calculated by AUCoral / AUCintravenous.
Why is bioavailabiity different between patients?
Affected by intestinal motility, food, age and first pass metabolism
What are the main factors which determine drug distribution? (ability to “dissolve” in the body)
Lipophilicity/hydrophilicity
Protein binding
What is an object drug?
Amount of drug administered lower than the binding site numbers (warfarin)