Pharmacokinetics and Pharmacodynamics Flashcards
what are the stages of the drug in the body
administration, absorption, transport, clinical effect, metabolism, excretion
what are the routes of administration
oral, transdermal, transmucosal, intravenous, intramuscular, subcutaenous, inhalation
what does enteral mean
via the gut
what does parenteral mean
not via the gut
what are the advantages of oral drug administration
socially acceptable, drug formulation can change onset and duration of action
what are the disadvantages of oral drug administration
slow onset, variable absorption, first pass metabolism
what is first pass metabolism
liver metabolising drug before it reaching the systemic circulation
what can first pass metabolism do?
inactivate or activate a proportion of the drug
what happens if first pass metabolism inactivates the drug?
more is needed by oral route to get desired clinical effect
what happens if first pass metabolism activates a drug?
makes an active form of an inactive drug, less needed by oral route
what are the advantages of IV and IM administraion
rapid onset, predictable plasma levels, no first pass metabolism
what are the disadvantages of IV and IM administration
allergic reactions more severe, short duration of action, access difficulties/self-medication, drug cost higher
what are the advantages of transdermal and SC administration
no first pass metabolism, allergic reactions very localised, prolonged action
what are the disadvantages of transdermal and SC administration
very slow onset, self-medication possible, drug cost higher, effect varies from person to person and site to site
what is bioavailability
proportion of an ingested drug that is available
what is bioavailability modified by
dosage form, route of administration, destruction in the gut, poor absorption, first pass metabolism
how is the drug dissolved
in the blood and transported bound to carriers
what is the drug bound to
plasma proteins - albumins
what does the speed of drug diffusion into tissues depend on?
blood flow to the area, blood wall vessel barrier, active secretion of the drug into the tissue
what is the single compartment model?
drug behaves as if it is evenly distributed throughout the body
what is the two compartment model?
drug behaves as if it is in equilibrium with different tissues in the body
what does significant lipid binding in the tissues mean?
slow release from accumulation so there is a prolonged effect
