*CH 46 Pharmacokinetics & routes administration Flashcards
(53 cards)
what is medication Absorption ?
Transmission of medication from location of administration to the blood stream
where does absorption take place?
GI tract, muscle, skin, subcutaneous tissue
What are common routes of administration enteral and parenteral?
Enteral: through GI tract
Parenteral: by injection
unique pattern of absorption ?
rate
amount
route
what are Oral route barriers to absorption
meds must pass through layer of epithelial calls that line GI tract.
oral route Absorption pattern
stability and solubility of meds GI pH and emptying time Food in stomach or intestine current meds form of med: coated, liquid
Subcutaneous and intramuscular barriers to absorption?
Their are none
Subcutaneous and intramuscular absorption pattern?
solubility of medication in water
blood perfusion at the site of injection
what are the two types of solubility of medication in water ?
high soluble meds = rapid absorption (10-30 min)
Poor soluble meds=slow absorption
what are the two blood perfusion types at the site of injection?
high blood perfusion = rapid absorption
low perfusion site = slow absorption
Are their any intravenous barriers to absorption?
no barriers
What are the two intravenous absorption pattern ?
Immediate; enters directly into the blood
Complete: reaches the blood in its entirely
what is the distribution of medication?
is the transportation of medication to the site of action by bodily fluids
What are the factors that influence distrubution?
circulation
permeability of the cell membrane
plasma protein binding
what condition can inhibit blood flow or perfusion
Peripheral vascular disease
cardiac disease
what is the permeability of the cell membrane ?
Meds must pass through tissue and membrane to reach targeted area.
what medication type can cross blood brain barrier and the placenta?
lipid soluble or medication that have transport system
What is plasma protein binding?
- medication compete for protein binding sites within the blood stream primarily albumin.
- 2 meds that compete for same binding site = toxicity
Metabolism (biotransformation)
changes meds into less active forms by action of enzymes.
where does metabolism take place
primarily Liver but also in kidneys, lungs, intestines blood
what are factors that influence med. metabolism rate
age increase in some meds-metabolizing enzymes First past effect similar pathways nutritional status
an increase in some med-metabolism enzymes
can metabolize some meds sooner = increase in dosage to maintain therapeutic level. can increase metabolism in other concurrent use of meds
First pass effect
liver inactivates some meds on first pass.
require nonenteral route (sublingual / IV)
Similar metabolic pathways
same pathways for 2 meds = alteration of 1 or 2 meds = decrease of one or both meds = accumulation
