Nurs 605 Module 1 Flashcards
What is pharmacokinetics?
how the body acts on the drug
specifically absorption, distribution, metabolism and excretion
used to individualize doses of drugs
What is pharmacodynamics?
how the drug acts on the body
what are the drugs mechanisms of actions on the body
Describe absorption
process of drug movement into the bloodstream
how fast the drug leaves the area of entry (oral, IV, IM) and what is the extent of this on the body
What is bioavailability?
percentage of the drug that reaches the bloodstream intact
Describe factors that affect absorption of a drug
formulation of the drug
pH of the body
acidity of the stomach
food, solubility
What are some routes of drug administration?
intravascular- intravenous or intraarterial
extravascular- oral, SL, IM, SQ, dermal, rectal
What is the first pass effect or first pass metabolism and how can it be avoided?
describes the drug “first passing” through the liver prior to reaching systemic distribution
greatly decreased the bioavailability of the drug
can be avoided by using routes that reach systemic circulation immediately ie) IV routes
Define evidence based medicine
using and applying best scientific evidence, clinical expertise, clinical expertise and patient specific values in order to guide decisions for individual patient care
Why is evidence based medicine necessary?
many "claims" out there that are not relevant guides clinical decision making what is best for your patient making informed decisions rarely one best answer that fits all
What is the evidence based medicine process?
identify problem
what is necessary to answer the question/problem
find current evidence -primary literature
evaluate the evidence
apply evidence to patient
evaluation
Define null hypothesis
assumption that there is no difference in treatment between group A and B
two treatments are equal
Define alternative hypothesis
opposite of null hypothesis
there is a difference in treatment between group A and group B
What does it mean to reject a null hypothesis?
that means there is a difference in treatment between group A and group B
rejection=there is a difference
Define internal validity
how accurate a study is in measuring what its supposed to measure
Define external validity
the study results are generalizable to the population outside of the study
Define sensitivity
a patient that is positive for a diagnosis will test positive
Define specificity
individuals without the specific condition will test negative for the condition
Define odds ratio
the ratio is the odd of developing a condition in an exposed group versus the odds of developing a condition in a non exposed group
What does it mean when an odds ratio is =1 ?
odds ratio =1 means the condition studied is likely to occur in both groups (ie group A and B)
What does it mean when an odds ratio is >1 ?
odds ratio > 1 means that the outcome is associated with the exposure or a ‘positive association’
Define relative risk
the risk of developing a condition when one is exposed vs. not exposed
ratio of risk of an event in people with a specific characteristic to those without the characteristic
Define relative risk reduction
proportional reduction in rates of bad events between experimental and control groups
what was the percentage of risk that was “reduced”
easier to visualize
Define relative risk reduction
proportional reduction in rates of bad events between experimental and control groups
what was the percentage of risk that was “reduced”
easier to visualize
must use relative risk reduction otherwise statistics on certain treatments can be misleading
Define distribution
movement of one drug from one part of the body through another
influenced by various factors
What is the rate of distribution and what are the factors that affect this?
rate of distribution is the speed by which one drug leaves one part of the body to another
influenced by: tissue/capillary perfusion-greater perfusion to an area means greater drug distribution
membrane permeability: certain membranes are tighter than others and allow drugs to pass through easily. blood brain barrier is tight membrane therefore allows less drug to pass through
affinity of the drug for tissues: dependent on the drug, hydrophilis vs. lipophilic (lipophilic drugs will pass fatty tissue easier than hydrophilic drugs)
What is the extent of a drug binding?
part of drug distribution
binding of drugs = bound drugs
drugs not bound= free drug
free drug will pass through different membranes and compartments such as blood/plasma and bind to proteins, there is an equal amount in order to reach accurate concentration
What is CYP450 and what is its action?
CYP450 is an enzyme in the liver that metabolizes most drugs
different enzymes metabolize different things
primarily works on drugs by removing or adding polar groups to the metabolized drug in order for it to be excreted by the kidneys
enzyme inhibitors=stops CYP450=stops metabolism=increased concentration of drug in the bloodstream
enzyme inducers = activates CYP450, makes it work faster= metabolism occurs faster=decreased levels of drug in the bloodstream
What are some factors that can affect drug metabolism?
route of drug age/gender nutritional status (low protein = less enzymes; less carbs=less ATP) enzyme inducers and inhibitors disease states
What is P-glycoprotein?
transport protein molecule
uses active transportt (ATP) to transport molecules into the urine, bile, etc for elimination
Describe half life (T1/2)
half life of a drug is the time it takes for 1/2 of the drug to be eliminated from the body
What is the relationship between steady state and IV infusions?
steady state is achieved with 95% of drug reaches the concentration of steady state
this occurs with IV drugs as there is a constant amount of drug in the blood
How many half lives does it take to completely eliminate a drug from the plasma or reach steady state with IV infusions?
4-5 half lives
Describe receptors
drugs acts on receptors in the body to block or illicit a biological response
Define agonist
agonists are drugs that bind to receptors and illicit a biological response
Define antagnoist
antagonists are drugs that block the receptors so bioloical responses do not occur
Define receptor upregulation
receptors can regulate themselves
upregulation means that there is little receptor or the receptors are contsatnly blocked so the body creates more
Define receptor downregulatio
downregulation means that the receptors are always being stimulated
