Intro to Pharmacology Flashcards
why do PTs need to understand pharmacology?
bc so many of our pts will be on medications (especially the geriatric population)
adverse drug events are a leading cause of death
what is the role of the PT in pharmacology?
review and monitor pt meds (prescriptions, OTC meds, homeopathic and herbal supplements)
monitor side effects
alert pt and physician of adverse rxns
assess how meds impact PT
what is the broad definition of a drug?
any chemical that alters physiologic fxn in an organism
would caffeine be a drug by the broad definition of a drug?
yes
what is the FDA definition of a drug?
chemical that the FDA allows medical professionals to use to diagnose, prevent, or treat
would caffeine be a drug under the FDA definition of a drug?
no
what is pharmacology?
the study of a drug on the human body
what is the FDA?
an agency of the US Dept of Health and Human Services that facilitates the availability of safe and effective drugs and provides clear and understandable drug info for safe and effective use
t/f: a drug MUST be demonstrated to be safe and efficacious b4 it is approved and marketed
true
t/f: safe means the complete absence of risk
false, it means free of serious side effects
t/f: safety is relative to the drug (ie Advil vs cancer meds)
true
how long does the research phase of the FDA approval process take?
2-4 years
how long does the pre-clinical phase of the FDA approval process take?
1-2 years
how long do the clinical phases of FDA approval take?
5-7 years
when are animals tested first in the FDA approval process?
in the pre-clinical phase
when are a small amount of human 1st used to test a drug?
phase one clinical
what happens in phase one clinical in the FDA approval process?
small number of humans are used
testing safety of the drug in healthy individuals
what happens in phase two clinical in the FDA approval process?
small number of patients with the condition are used to test efficacy of the drug
what happens in phase three clinical in the FDA approval process?
1000s of affected individuals are used to further determine the efficacy of the drug
when is an IND application put in?
after the pre-clinical phase
what happens in phase 4 of the FDA approval process?
the drug is manufactured, marketed, and administered
post market surveillance for long term effects
available to the public
FDA approval
what does dispensing mean?
how the drug is administered
how are most OTC meds dispensed?
orally
t/f: OTC meds usually have milder safety concerns than prescription drugs
true
t/f: prescription drugs can have a higher dose than OTC meds
true
t/f: OTC meds can still have serious adverse/side effects when overdosed
true
t/f: OTC meds should be included in the initial eval
true
can prescription drugs become OTC over time?
yes!
generic name and brand name drugs are ___
bioequivalents
what is the chemical name of a drug?
the active ingredient
what is the generic name of a drug?
the shortened name of the chemical name
t/f: there are often many brand names for the same generic name drug
true
what does the therapeutic classification of a drug tell us?
what the drug is trying to treat?
what are some examples of therapeutic classifications of drugs?
anticoagulant, antihypertensive, antihyperlipidemic, antidysrhythmic, or antianginal
what does the pharmacological classification of a drug tell us?
the mechanism of action (how the drug works)
what are some examples of pharmacological classifications of antihypertensives?
diuretic, calcium channel blocker, ACE inhibitor, adrenergic antagonist, vasodilator
what is pharmacokinetics?
how the drug changes as it moves in the body (absorption, metabolism, distribution, excretion)
what the body does to the drug
what is pharmacodynamics?
effects of a drug on the body
what a drug does to the body
ID mechanism of action and how it interacts with the body to produce therapeutic and side effects
what elements are included in pharmacokinetics?
route of administration
absorption
metabolism
distribution
elimination
what are the 2 man classifications for routes of drug administration?
1) enteral administration
2) parenteral administration
what is enteral administration?
administration of a drug via the GI tract
what is the most common enteric administration?
oral
what is the pathway of oral meds?
mouth–>GI tract–>liver–>systemic circulation
what are the types of enteric administration?
oral
sublingual
buccal
rectal
how are sublingual drugs administered?
under the tongue
how are buccal drugs administered?
bw the gums and cheek
t/f: sublingual and buccal meds are not chewed or swallowed, but dissolved
true
do drugs administered sublingually or buccally go through the liver?
no
what is the pathway of drugs administered sublingually or buccally?
absorbed by submucosa–>venous system
does oral or sublingual and buccal administration have faster delivery and usually lower dosage?
sublingual/buccal administration
what portion of rectal circulation bypasses the hepatic portal?
2/3
t/f: rectal administration of drugs can irritate the mucosal lining of the rectum
true
what is parenteral administration?
administration of a drug outside of the GI tract
what are some examples of parenteral administration?
vaccines, inhaler, creams, patches, nose spray, ear drops, eye drops
what are some examples of topical parenteral administration?
eye drops, ointments, creams
what is an example of transdermal parenteral administration?
patches
is enteral or parenteral administration more predictable delivery
parenteral
what is the pathway of drugs administered orally?
stomach–>intestines–>portal circulation–>systemic circulation
what is the pathway of drugs administered parenterally?
intravenous–>system circulation
t/f: drugs going through the liver can leave some inactive or active
true
metabolism __ biotransformation
=
what is metabolism/biotransformation?
chemically altering the og drug compound
changes drug from active to inactive/less active
what is the primary organ of metabolism?
the liver
what happens if the liver enzymes are not working well or are absent?
the 1st pass effect is decreased
do oral meds go through biotransformation?
yes
if a drug goes through biotransformation, does there need to be a higher or lower dose of the drug for it to work?
higher dose
what is the 1st pass effect?
determines how much of the drug is lost during absorption b4 the drug reaches systemic circulation
if a drug has an 80% 1st pass effect, what % of the drug reaches systemic circulation?
20%
t/f: oral administration is simple but has less predictable absorption
true
what is a common side effect of oral meds?
GI discomfort
is enteral or parenteral administration less convenient but has more predictable absorption?
parenteral administration
does parenteral administration have a 1st pass effect?
no
what is bioavailability?
% of the drug that reaches the systemic circulation
the 1st pass effect ___ bioavailability of a drug
decreases
if 20 g of a drug is given and 10 g reaches the target, what is the bioavailability of the drug?
50%
what factors does bioavailability rely on?
route of administration
lipid solubility
environment of the GI tract
drug concentration
do lipid soluble drug cross the membranes easier?
yes
do ulcer increase or decrease drug absorption and bioavailability?
decrease
what is drug distribution?
drug delivery from the bloodstream to the tissues
what factors are involved in tissue permeability?
lipid soluability
blood brain barrier
are highly perfused organs receiving more or less of the drug?
more
are low perfused organs receiving more or less of the drug?
less
what things can increase perfusion?
heat and exercise
what organs are highly perfused?
brain, liver, heart, lungs, kidneys
t/f: ONLY unbound drugs can reach target tissue
true
when drugs bind to subcellular components do the drugs have any effects on the body?
no bc the drug can’t be distributed
where does a lot of drug storage occur?
in adipose tissues
t/f: adipose tissue has low perfusion and low metabolism
true
are drugs stored in the adipose tissues for a long or short time?
long time
why is early mobilization key in patients?
bc it increases perfusion and therefore releases the stored drugs in adipose tissue and they can then be excreted faster
what other areas (other than adipose tissue) store drugs?
bone, muscles, organs
what drugs do bones store?
heavy metals (ie lead) and antibiotics (ie tetracyclines)
what organs tend to store drugs even though they are highly perfused?
the liver and kidneys
at drugs are especially stored in adipose tissues?
anesthetics
what are the adverse effects of drug storage?
local tissue damage
redistribution of drugs from storage
what structures are damaged by lead poisoning?
CNS, bone, and GI tract
what is an organ frequently damaged by meds?
the liver
what is the result of redistribution of drugs from storage?
prolonged effects of a drug or extended adverse effects
what is the downside of lipid soluble drugs?
they are easily stored in adipose tissues
what is the role of drug elimination?
termination of their effects and prevention of excessive accumulation
elimination of drugs occurs primarily in what organ?
the kidneys
what is the most common route of drug elimination?
urine
besides urine, what are other routes of excretion?
feces, sweat, saliva, lungs (exhaling)
if the kidneys are damaged, what happens to drug excretion?
drug excretion is reduced and drug retention and circulation is increased
what is drug clearance?
efficiency of drug removal from the body
the theoretical volume of blood that is cleared of the drug per unit of time
can drug clearance be measured?
no
do we use clearance or half life more often in the clinic?
half life
what is the half-life of a drug?
the time required for 50% of the drug remaining in the body to be eliminated
if a drug has a 1/2 life of 2 hours, in a 2 hour period, how much of the drug remains in the body?
50%
what is the importance of half life to PTs?
we need to educate our patients on the importance of keeping to their dosing schedule and compliance to their med regimine
what are factors affecting pharmacokinetics?
age, gender, disease, genetics, body composition, diet, and physical factors
t/f: babies have limited kidney and liver fxns that slows drug movement in the body
true
t/f: the elderly have slowed metabolic processes that effect pharmacokinetics
true
t/f: hormones and enzyme differences bw males and females has no effect on pharmacokinetics
false, they do
vitamin K found in leafy greens interferes with what drugs?
blood thinners
grapefruit prevents the liver from processing what drugs?
statins (antihyperlipidemic)
what are physical factors that effect pharmacokinetics?
exercise, heat, and cold
efficacy=_____ ______
therapeutic response
t/f: drugs work by binding to target receptors
true
what is an agonist?
a drug that initiates a change in the fxn of a cell
what is an antagonist?
“-blockers” that stop/inhibit change
what is affinity?
attraction of drug and receptors
do agonists or antagonists have affinity for receptors?
both!
what is efficacy?
effectiveness of a med in activating the receptor
do agonists or antagonists have efficacy?
only agonists
what is a selective drug?
a drug that activates only some receptors
what is a non-selective drug?
a drug that activates all receptors
t/f: drug activation of receptors is an all or nothing event
false
t/f: you can have full or partial agonists and antagonists that activate/inhibit partial % of the action or all of the action
true
t/f: long term drug use can change receptors and therefore habituate/develop a tolerance
true
what is dosage?
the min amount of a drug that produces the best therapeutic response and min unwanted/toxic effects
dosage varies depending on what 3 factors?
1) disease/symptoms to be treated
2) presence of other diseases
3) polypharmacy
t/f: dif conditions can be treated with dif doses of the same drug
true
what is polypharmacy?
taking 3 or more meds for a condition
people taking multiple meds
what is the dose-response relationship?
physiologic response to a drug that is dependent upon the # of receptors bound by the drug
in the dose-response relationship curve, should the toxic response curve be to the right or the left of the effective dose curve?
to the right bc the therapeutic effect should occur first
what is the max effect of a drug?
the plateau where there are no more receptors for the drug to bind to
if the toxic response curve is to the left of the effective dose curve, what does this mean?
bad news!!!!!
the drug has toxic effects before it can have any therapeutic effects
the further to the right the toxic response curve is compared to the effective dose curve, the ___ the drug
safer
what is the therapeutic index (TI)?
the ratio of mean toxic dose to mean effective dose (TI=TD50/ED50)
the therapeutic index should be greater than what number?
1
the larger the space bw TD50 and ED50 (TI), the ___ the drug
safer
when the TI is small, what should be done frequently?
blood withdrawal to make sure that the drug levels don’t go beyond the therapeutic range
t/f: TI is an indicator of safety
true
is a drug with a TI of 40:1 or 2:1 safer?
40:1
what is the therapeutic window?
the range of a drug dose that can treat a disease effectively w/o having toxic effects
the larger the therapeutic window, the __the drug
safer
the onset of action (how quickly the therapeutic level is achieved) depends on what ?
the rate of absorption and distribution of the drug
is rate of absorption and distribution a characteristic of pharmacokinetics or pharmacodynamics?
pharmacokinetics
what is MECadverse?
the min effective concentration for adverse effects
what is MECdesired?
the min effective concentration for desired effects
if a drug is rapidly released, does it reach the therapeutic effects faster or slower?
faster
t/f: dif routes of administration reach the therapeutic range at dif rates
true
what is potency?
the amount of a drug required to produce the desired response
if drug A at 25 mg produces the same response as drug B at 50 mg, is drug A or B more potent?
drug A
t/f: the least amount of a drug need to achieve a % response is the most potent drug
true
will full agonists/antagonists be more or less potent?
more potent
what is the maximal efficacy of a drug?
the extent to which a drug can produce a response when all available receptors or binding sites are occupied
what is the effectiveness of a drug?
how well a drug works in real-world use
are drugs that are efficacious in clinical trials usually more or less effective in real world use?
less bc there is less control of outside factors like adherence and nutrition
what is a drug interaction?
a rxn bw 2 or more drugs/bw a drug and a food/supplement
when tums is taken with NSAIDs what happens?
the tums decreases the effectiveness of the NSAID
can be good bc it protects the gut
should PTs tell pts to hold out of taking meds until after PT bc it interferes with exercise?
no! schedule their PT around their med regimine
what are the s/s of an allergic response?
hives (contact dermatitis), skin rash with or w/o itching, edema, runny nose, red eyes with tearing
what are the immunological responses to a drug?
allergic reaction
anaphylaxis
what is anaphylaxis?
a severe systemic allergic reaction involving multiple systems
what is anaphylactic shock?
a life-threatening decrease in BP that results from an allergic reaction
what are the s/s of anaphylaxis?
acute dyspnea, sudden hypotension, tachycardia, SOB, rapid swelling of the throat, hives, unconsciousness
