Pharmacokinetics Flashcards
what is the sequence of pharmacokinetics? (4)
- drug absortion
- drug distribution
- metabolism
- drug elimination
What is pharmacokinetics?
the movement and proceess of a drug in the body
what are the concepts of pharmacology? (5)
- Therapeutic range
- Dosage regimen
- Route of administration
- Pharmacokinetics
- Drug effect
Drug absortion is…
the movement of the drug from the administration site into systemic circulation
how is drug absorption affected? (6)
- route
- hydrophilic/lipophilic
- drug form
- GIT condition
- liver metabolism
- blood perfusion
which routes allow for systemic distribution? (5)
- IV
- IM
- SQ
- IP
- intramedulary
what affects the route of administration?
how is drug affected?
physical barriers
onset of effect is slower
what can effect drug distribution?
how?
protein binding
makes molecule to large to pass through tissue
drug distribution is…
drug being transported to systemic circulation
once in systemic circulation where is drug distributed?
target tissue
where is the main area of drug metabolism?
liver
what is drug metabolism?
drug is metabolised by the liver before it can have an effect on the body
what are some drug interaction during metabolism? (2)
- competative inhibition
2. enzyme induction
what happens during drug metabolism?
enzymes in the body transform drugs into secondary compounds
what happens during the first step of drug metabolism?
origional drug is transformed into metabolite 1
what happens during the second step of drug metabolism?
metabolite 1 is transformed into metabolite 2
what are secondary compounds
metabolites
what polarity are metabolites?
hydrophilics
where are metalolite excreted?
urine
what chemicals does metabolite 1 combine with? (3)
- glucuronic acid
- sulfate
- glycine
drug elimination is…
removal of drugs from the body
where does drug elimination occur? (2)
kidney
and
liver
what can poor renal flow cause with drug elimination lead to?
toxicity
where are drugs primarily transformed?
liver
what factors determine route of administration? (2)
drug form
and
route
what are some administration routes?
- topical
- oral
- inhalant
- parenteral
dosage interval is…
length of time between doses
dose is…
amount given at one time
blood perfusion is…
alteration of blood flow affecting absorption rate
what determines dosage regimen? (2)
dose
and
dosage interval
dose regimen is…
the amount, frequency, and duration of a drug administration
how is a theraputic range maintained?
if amount entering = amount leaving
what part of theraputic range can be controlled?
amount entering
what part of theraputic range CAN NOT be controlled?
amount leaving
theraputic range is…
plasma concentration at which a drug exerts its desired affect
what GI conditon can affect absorption? (3)
- abnormal motility
- mucosal inflammation
- loss of epithelial cells
what determins the process of pharmacokinetics? (2)
nature of drug
and
bodys response to drug
what is the polarity affect of drugs?
molecules ability to move across physical barriers
how does solid drug form affect absorption?
must be broken down before absorpiton
what is the lipophilic drugs effect?
diffuse across cellular membranes
which drug route is for lipophilc drugs?
oral
what is the hydrophilic drugs effect?
diffuse through fluids between cells
which drug route is for hydrophilic drugs?
parenteral
what is bioavailability?
the portion of drug that makes it to systemic circulation
what van affect the concentration reached by a drug in the blood stream? (2)
- the fluid volume into which it will be distributed
2. The extent to which it will be distributed throughout the body
non-receptor mediated drugs are…
drugs that exert therin effect with/out binding to a receptor
what cellular effects are observed after drug bind to receptor? (3)
- secretion of a substance
- contraction of muscle cells
- cell death
what is the action of an agonist drug?
has affinity and efficacy
what is the action of an partial agonist drug?
has affinity but poor efficacy
what is the action of antagonist drug?
NO action
what are the different types of drug effects?
- agonist
- partial agonist
- antagonist
what is drug effect?
when a drug combines with cellular receptors to exert their effect
what is the componet to drug effect?
cellular receptors
what are some possible drug residue effects? (3)
- allergies
- carcinogens
- bacterial resistance
why are withdrawal time so important?
drug residues can be dangerous for people
what is a drugs half life?
the amount of time it take for drugs in the blood to decrease by 1/2
what is drug half life used to determine? (2)
dosage interval
and
withdrawal time
what does drug elimination depend on?
drugs half life
