Units2/3 Flashcards
what is the great is barrier for drugs?
Crossing the membrane that separates the drug from the target cells.
simple/passive diffusion
movement of a chemical from an area of higher concentration to an area of lower concentration.
facilitated diffusion
no energy need to diffuse but a carrier protein is
active transport
energy is need for transport to move molecules against the gradient
pharmacokinetics
the study of drugs within the body
absorption
the rate, extent, and process of moving a drug from the sight of administration to the blood stream
oral med absorption
absorbed in GI or intestine, slow absorption and a slow onset time
Topical med absorption
skin or mucous membranes, absorbed slowly in the skin and quickly in the mucous membrane
onset
the length of time it takes a drug to produce and affect
If the absorption rate is high what happens to the response?
produces a more effective response
what has the fastest absorption rate?
IV
What is the advantage of administering a medication intradermally?
it has a slow absorption and the effect is localized
the _____ absorption, the _____ the onset.
faster, faster
What are the advantages of transdermal drug delivery system?
slow, steady absorption
what are the disadvantages of transdermal drug delivery system?
skin irritation, slow onset time
What are some factors that effect drug absorption?
- dosage form of the drug (pill vs liquid vs cream, etc)
- concentration of the drug
- solubility (fat vs water)
- blood flow
- contact time with absorption site
- presence of food
- surface area
What does food do to absorption?
slows it down
what happens to absorption with a higher dose of a drug?
produce a faster, greater response, because it produces a higher concentration gradient
Bioavailaability
amount of drug that is able to reach the target site to produce it’s effect
first pass effect
drug metabolized by the liver before it’s able to reach systemic circulation
Distribution
the movement of drugs fom body fluids to body tissues after they are absorbed
what hinders distribution?
bad blood flow to tissues, drug solubility, tissue storage, drug protein binding, barriers
free drug
drugs not bound to to plasma proteins, the drugs not bound are able to act on body cells
metabolism/biotransformation
method of changing a drug to be more easily excreted
what is a prodrug
a drug that can be activated and used until it is metabolized
induction
increased enzyme production
what is the result of induction
more drug metabolized and need higher dose
inhibition
inhibiting liver enzymes
what is the result of inhibition?
less drug metabolized and more drug in the blood
what effects metabolism?
- lifespan/age
- lifestyle
- diet
- habits
- genetics
Excretion
elimination of a drug, either unchanged or as a metabolite from the body
What happens when drugs are secreted in the bile?
reabsorbed so metabolites may be recycled multiple times
serum drug level
amount of drug in the blood
minimum effective concentration (MEC)
amount of drug in the blood required to get a drug action
toxic concentration
too much drug causes toxic reactions
therapeutic range
between the MEC and Toxic concentration levels
therapeutic index
margin of safety of a drug
loading dose
a large initial dosing of a drug to achieve rapid minimum effective concentration in the plasma
peak and trough levels
highest and lowest plasma concentration of a drug
maintenance dose
drugs given to keep plasma drug levels in therapeutic range.
peak
highest blood level
duration
length of pharmacological action
serum half life
time required for serum concentration to be decreased by 50%
What needs to happen when you have short half life? a long half life?
more frequent dosing, less frequent dosing
potency
the dose at which a drug will produce it’s therapeautic effect
pharmacodynamics
how the drug changes the body
efficiancy
the greatest response that can come from a drug
receptors
drug binding sites, effect can stimulate or inhibit cell function,
agonist
promote or produce a response
antagonist
block a response
partial agonist
produces a weaker or less efficient response to a drug
down regulation
receptor desensitization can occur through repeated or long term stimulation
up regualation
excess excitatory responses can be noted if receptor has been repressed for a long time and then a small dose of a stimulating drug is given.
specificity/selectivity
how many different receptors the drug will effect
adverse effect
a reaction that occurs other than the desired therapeutic effects of drug therapy
Adverse drug reactions
- result in patient death, hospitalization or disability
- cause a congenital abnormality
- cause a life threatening event
- require an intervention to prevent permanent damage
what can a nurse do prevent adverse effects?
- take a thorough medical history
- thoroughly assess the patient and all diagnostic data
- prevent medication errors
- monitor pharmocotherapy closely
- know the drugs
- be prepared for the unusual
- question unusual orders
- teach patients about adverse effects
hypersensitivity
abnormal exaggerated response to an antigen
drug allergy
abnormal reaction to a drug because of prior exposure stimulated the immune system to develop antibodies
anaphlaxis
most serious allergic reaction. a medical emergency, with systemic reaction evidenced by dyspnea, cardiac arrhythmia, laryngeal edema, broncospasm, and circulatory collapse.
idiosyncratic drug response
an unanticipated or unexplainable response to a drug, often referred to as a paradoxical response, is not considered an allergic response, rare unpredictable varies from patient to patient
carcinogen
drug that many cause cancer
teratogen
drug that may cause birth defect
pregnancy classifications
A, B, C, D, X
Additive effect
when 2 drugs from the same therapeutic class are used together for a greater response
synergistic effect
when 2 drugs create a bigger response than what you would think if you simply combined them together
antagonistic
one drug blocks the effects of another drug
displacement
displacing one drug from protein binding sites increases the amount of free drug thereby increasing the drug effect.
antidote
reverse or block the toxic effects of another drug
binding
drug binds with another drug or food and is unable to be absorbed
enzyme induction
increases liver metabolism of drugs
drug tolerance
needing more drug to achieve desired effect
signs of drug dependence
withdrawal, physical dependence, psychological dependence drug seeking behavior
management of a drug overdose
recognition or identification of drugs taken, gastric lavage, activated charcoal, and whole bowel irrigation
treat life threatening symptoms
administer antidotes
