pharma Flashcards
define pharmacokinetics
what the body does to the drug
define pharmacodynamics
what drug does to body
list the 4 four pharmacokinetic processes
ADME
-absorption
-distribution
-metabolism
-excretion
what is absorption
transfer of drug molecule from site of administration to systemic circulation
name so local routes of administration
topical
intranasal
eye drops
transdermal*
inhaled*
what are the two routes of systemic administration
enteral - GI tract
oral, sublingual, rectal
par-enteral- not GI tract
IV, IM, SC
3 mechanisms for drug permeation across cell membranes
- passive diffusion via hydrophobic membrane, lipid soluble molecules
-passive diffusion aqueous pores, v. small h20 soluble drugs
-carrier mediated transport
what needs to happen for an ionised drug to be absorbed into blood
must be unionised
where are weak acids best absorbed
stomach
where are weak bases best absorbed
intestine
name 5 factors the affect oral drug absorption
- gastric enzymes, may digest drug molecule
- low ph, molecule may be degraded
- food, full stomach means slower absorption
-gastric motility
-previous surgery
3 factors affecting oral drug absorption in the intestine
- drug structure
-medicine formulation/release time - p-glycoprotein
define first past metabolism
metabolism of drugs preventing them from reaching systemic circulation
how can you avoid first pass metabolism
give drugs via routes that avoid splanchnic circulation,, eg rectal
what is bioavaliability
proportion of administered drug that reaches the systemic circulation