therapeutic drug monitoring Flashcards
(56 cards)
if drug is too low
ineffective
if drug too high
toxic
routes of administration
IV
IM
Orally
specimen of choice
serum or plasma
what kind of tube do we not wanna use
lithium heparin
-this is a medication
Do not use a serum separator when doing drug monitoring because
drugs will be absorbed into gel substance (false negatives)
-should be separated asap
most drugs stable at
RT for 24 hrs and 2 days in fridge
specimen for drugs of abuse
urine
-look for metabolite of drug
when is peak
drawn 1 hour after dosage
when is trough
drawn for hour or 30 min before next dosage
absorption
-process of drug being taken up in system
IV absorption fastest
first pass metabolism
absorbed from GI tract must go through liver first before going through general circulation
-in liver disease we want to bypass this
bioavailability
once absorbed into system how much is available for distribution
-affects oral medication the most
free drug interact with
target site
1 protein drugs will bind to
albumin
if decreased albumin
toxic amount of drugs
(more free floating around)
if increased albumin
-dehydration
-decreased amount of drug
drug distribution
-how much do we want to go
-free drugs diffused very well into interstitial and intracellular spaces
polar drugs- diffused easily out of circulation
Parent drug broken down into
metabolite; water soluble and easily excreted
factors that affect metabolism
○ Weight
○ Age - metabolize drug slowly (old people can go into toxicity)
○ Other medications
○ Disease states
○ Children versus adults
§ Children metabolize drug fast because of body weight
why do newborns not metabolize well
liver is not mature
if drug is not used pass out through
kidney excretion and liver metabolism
-1st order kinetics play a role in metabolize and clearing
how many doses to reach steady state drug level
5-7
-want to remain here
what is half life
Time required for serum drug concentration to decrease by 50%
-dosage is done according to
