Exam 1 Flashcards
what is most important concept of an “ideal drug”
effectiveness - does what it’s supposed to do
what is the therapeutic objective for drugs?
maximize benefit, minimize harm
pharmacokinetics definition
body’s impact on the drug; movement of drug through body
components of pharmacokinetics
absorption, distribution, metabolism, excretion
where are drugs metabolized?
liver
where are drugs excreted?
kidneys
pharmacodynamics definition
impact of drugs on the body
5 rights of medication administration
right medication, right person, right dose, right time, right route
controlled substances
drugs with potential for abuse
what populations are being tested in preclinical drug trials?
animals and human cells
what populations are being tested in clinical drug trials?
humans
which populations are tested in phases 1, 2 and 3 of clinical trials?
1-healthy
2-people with disease being targeted
3-people in hospital (largest sample size)
what is phase 4 of clinical trials? what is being monitored?
post marketing surveillance; ADRs being monitored
define drug classification of therapeutic
broad definition - ex: hypertensive, antidepressant
define drug classification of pharmacological
mechanism of action - ex: beta blocker, SSRI
what is the difference and concern with generics vs brand drugs?
generics have different INACTIVE ingredients and rate of absorption is affected
name ways drugs can cross membranes into site of action
channels and pores (small), transport systems, direct penetration
which is most common way drugs cross membranes?
direct penetration
cells must have what characteristic to pass through via direct penetration
lipid soluble (b/c of the lipid membrane)
what types of drugs cannot pass via direct penetration?
ions, polar molecules
define absorption of drugs
movement from site to bloodstream
what factors affect absorption
how quickly it dissolves, lipid solubility, blood flow, surface area (increases in these will cause increased absorption)
what is the quickest administration route?
parenteral - IV, SQ, IM! - straight into bloodstream
how does protein binding affect distribution of drugs?
drugs bind to albumin, a large protein molecule in the blood. some drugs have a higher affinity for albumin. albumin is too large to pass through the membranes, so it will decrease the number of drug molecules that will make to the site of action, or be excreted. since albumin has a limited number of binding sites, and can knock other drugs off, there are toxicity concerns
describe CYP450
a family of enzymes that is responsible for the metabolism of most drugs - 12 total, 5 responsible for most!
describe first pass effect
rapid inactivation of oral drugs in the liver; this will decrease the therapeutic effect and decrease amount of drug in the body; explains why oral meds have a LARGER dose compared to IV meds
how are drugs excreted from the body? what needs to be checked? but what is often checked and used in Davis Drug Guide (and not done correctly)
kidneys; GFR; creatinine clearance
passive tubular reabsorption
drugs reabsorbed back into bloodstream
active tubular excretion
drugs pumped into urine and excreted
what is therapeutic window?
area between minimal concentration of a drug and toxicity
OTC drugs have what type of therapeutic window?
BROAD - much safer
half life
time it takes for drug to be reduced by 50% in the body
average number of half lives for drug to reach plateau? what is plateau?
4 x; amount excreted = amount administered (steady state)
efficacy vs potency
efficacy is the largest response a drug will produce (tylenol will never produce a response like morphine) and potency is the amount needed to produce the same effect (a drug is more potent with a lower # of mg - needs less to produce effect)
define agonist
has affinity and intrinsic factor (activates receptors when it binds) - mimics body’s response
define antagonist
has affinity but no intrinsic factor (DOESN’T activate) - BLOCKS response
ED50
dose needed to produce therapeutic response in 50% of population
LD50
lethal dose in 50% of animals
greater distance between ED50 and LD50 means what?
larger therapeutic index = safer drug!
define side effect
predictable, expected response to a drug (drowsiness with benadryl)
most allergic reactions to drugs are seen with which drugs?
penicillin, Sulfa drugs, NSAIDs
define paradoxical effect
opposite of what’s expected (kids becoming hyperactive when given benadryl)
idiosyncratic effect
all over the place, unpredictable, uncommon
teratogenic effect
= causes malformations; impacts development of fetus (most often in 1st trimester)
iatrogenic disease
caused by normal dosing; patient appears to have another drug and will disappear when drug is removed (lupus, parkinsonism)
what should be monitored with the liver for ADRs?
liver function tests - AST, ALT (if elevated = liver damage)
s+s of hepatitis (to monitor for hepatotoxicity)
jaundice, RUQ pain, nausea, anorexia, light colored stool
what should be monitored with the kidneys for ADRs?
BUN, GFR, creatinine
physical dependence vs psychological
physical - will have physical withdrawal symptoms where as psychological you will “lie, cheat, steal or do anything” to get your hands on the drug
difference between side effect and adverse drug reaction
side effect is expected and predictable whereas an ADR is noxious, unintended, undesired
what are the steps of the nursing response when a medication error has occured?
ASSESS PATIENT*, tell provider, inform supervisor, fill out incident report
additive response
1+1=2, same response as if given separately
potentiate response
a+b=B, one drug increases response of another
synergistic response
1+1=5, one drug amplifies the other
antagonism response
1+1=0, one drug blocks the other
idiosyncratic response
1+1=450, -60, or 22, all over the place, no pattern
inhibitory response
1+1=0.5, one drug reduces the effect of another
drug interactions are mostly seen with what type of drugs
IV meds
grapefruit and grapefruit juice can impact metabolism of what drugs?
SSRIs, calcium channel blockers, statins, transplant drugs, versed
what is the leading cause of acute liver failure?
DRUGS!
pharmacodynamic tolerance
gradually needing more of the drug to get same response
tachyphylaxis
response to drug decreases with repeated dosing
how does kidney disease and liver disease impact absorption of drugs?
both diseases will cause decreased functioning of those organs, which will decrease metabolism and excretion, causing toxic levels of drug in the body
with genetics (CYP450), describe what you would see with an ultra-rapid metabolizer ?
they would have increased metabolism of drugs. with an active drug, you would have decreased levels and a lesser therapeutic response. with a pro drug, you would have more drug metabolized into the active drug, which could cause toxicity levels
with genetics (CYP450), describe what you would see with a poor metabolizer?
they would have decreased metabolism of drugs. with an active drug, there would be increased levels, leading to toxicity. with a pro drug, you would have less metabolized into the active drug, so low levels and a lesser therapeutic response
name some factors that impact medication adherence
manual dexterity, physical ability, cognitive/intellectual ability, resources, belief that drug will work, cost, drug-drug or drug-food interactions
discuss physiological changes that happen during pregnancy that impact pharmacokinetics
increased renal and hepatic blood flow - in the liver this metabolizes drugs quicker, and in kidneys this causes drugs to be excreted more quickly. pregnancy also causes decrease motility in the GI tract which can increase absorption due to the drug staying in the GI tract longer.
when do teratogens have the most impact on fetus? why?
first trimester/embryonic phase** - organs are developing during this phase
the impact of teratogens in 3rd trimester will mostly cause what?
functional issues (as opposed to developmental malfunctions)
what are some strategies to minimize risk of drug transfer during breastfeeding?
- take drug RIGHT after breastfeeding
- chose drugs with short half life
- chose drugs that are known to stay out of milk
- avoid drugs that are known harm to infant
what age are children at most risk for ADR? why?
before 1 year of age - organ immaturity
dosing for children is mostly based on what?
Body Surface Area
strategies to promote drug adherence in children
- make it tase good :)
- educate and demonstrate to parents
- have proper measuring tool
- system for multiple caregivers
physiological changes in older adults that impact pharmacokinetics
- decreased organ function (decreased absorption and excretion)
- increased body fat (increases lipid solubility)
- decreased muscle mass (decreases protein binding)
- decreased GI motility/delayed gastric emptying (decreased absorption)
what factors promote med adherence in older adults?
- easy, simple system
- clear, concise directions
- easy to open bottles
what impacts med adherence the MOST?
belief that drug is needed (type of medication, dose, frequency)
