Introduction to Pharmacokinetics Flashcards
What factors can affect the pharmacokinetics of a drug?
Genetics - individuals may metabolise drugs differently due to their genetics; Weight - can impact the volume of distribution; Age - infants have incompletely developed elimination mechanisms and the elderly have decreased renal clearance; Presence of disease.
What are some factors that affect the absorption of drugs given orally?
Molecular weight of the drug; Lipid solubility of the drug; Ionisation of the drug; Fed vs Fasted states; GIT motility (gastric stasis and hypermotility of the intestines can both decrease absorption); Splanchnic blood flow.
How do drugs move across cell barriers?
Drugs can cross cell membranes by: (1) diffusing through the lipid; (2) via a carrier; (3) by diffusing through aquaporins; (4) by pinocytosis.
Explain ion trapping of drugs.
When a lipid soluble drug diffuses into a cell, it can be metabolised –> the product may be charged –> this means that the metabolite is now trapped inside the cell as polar molecules are not lipid soluble.
What are the four aspects of pharmacokinetics?
ADME Adsorption Distribution Metabolism Excretion
