Flashcards in Session 1 Deck (10):
When should drugs be reported on a yellow card?
All reactions to black triangle drugs (new)
All peadiatric reactions
All serious complications (prolonging hospital stay) of established products
Define pharmacokinetics and pharmacodynamics
Pharmacokinetics - movement of drug in/out of the body (what body does to drug)
Pharmacodynamics - mechanism of action (what drug does to body)
What are the 4 steps in the pharmacokinetic process?
Absorption - bioavailability, first pass metabolism
Distribution - protein binding, volume of distribution
What is the bioavailability (F) of a drug and how is it calclated?
The fraction of a drug that finds its way into the circulation. Two graphs of plasma concentration against time are plotted for oral and IV (100%) routes. F=AUC oral/ AUC IV
What factors affect bioavailability?
Absorption - age, vomiting, malabsorption
First pass metabolism
What is the first pass metabolism?
Any metabolism occuring before the drug enters the systemic circulation. Occurs in the gut lumen, gut wall and liver
What factors can affect drug protein binding?
Hypoalbuminaemia, pregnancy, renal failure, displacement by other drugs
When is a change is the protein binding of a drug significant?
If the drug has high protein binding, low Vd and narrow therapeutic window
What factors can influence the activity of cytochrome P450 enzymes (phase 1 metabolism)?
Enzyme inducing/inhibiting drugs (alter rate of metabolism of other drugs), age, liver disease, cigarettes, alcohol