Exam Two - Key Foundational Concepts Flashcards
Pharmacology
study of drugs, actions, and reaction
PD
pharmacodynamics
Pharmacodynamics
“What the drug does to the body” this can be the desired therapeutic response, physiologic changes as well as adverse reactions/toxicities
PK
Pharmacokinetics
Pharmacokinetcs
“What the body does to the drug” full range of absorption, distribution, metabolism and excretion (ADME). May also include accumulation/toxicity
Pharmacy
involves therapeutic use of drugs as well as medication safety, inventory control and distribution systems
does-response relationships
as drug concentration increases, some maximal effect is reached (Emax)
At half maximal effect
EC50
a description of potency
Graded dose-response curve
degree of response varies with dose
Quantal dose-response curve
average effect of a drug as a function of concentration in a given population
effective (efficacious)
the ability of a drug to produce the desired effect
Therapeutic Index (TI)
a range (index) of drug concentrations/doses needed to produce DESIRED THERAPEUTIC EFFECTS BELOW the level required to produce significant TOXICITY
Therapeutic Window
want wide therapeutic windows. This means we have a lots of dosing room for desired effects before we hit toxicity. “safer” than those with narrow windows
Narrow TI
drugs that have a small “dosing range”. The therapeutic dose is often only slightly above the non-effective dose and only slightly below a toxic dose.
careful dosing calculations/monitoring required for safe use
small dose changes may produce BIG concentration changes
Examples of narrow TI drugs
some seizure meds, gidoxin, aminoglycoside ABX, some chemo agents, lithium, warfarin, etc
Formula for TI
TI = TD50/ED50
What is an example for an Alpha 1 agonist?
vasopressor support
What is an example for Beta agonists?
inhalers for asthma and copd
other examples of drugs working via receptors
histamine H1 & H2 receptors
muscarinic receptors
Physiological effects and opioid receptors
mu, kappa, and delta receptors
Mu receptors are responsible for
- analgesia
- respiratory depression
-Euphoria - sedation
- physical dependence
- slowed GI transit
- miosis
-modulation of hormone and NT release
Kappa receptors are responsible for
-analgesia
-minimal respiratory depression
- dysphoria
-mild sedation
-slowed GI transit
-miosis
-psychomimetic effects
delta receptors are responsible for
-analgesia
-modulation of hormone and NT release
Explain why we need dose tapering
receptor density on a cell can become upregulated or downregulated. If a drug chronically blocks a receptor, the cell will make more of that receptor. If you suddenly take away the drug, the cell will have way too many receptors which could have disastrous consequences (ex. beta blockers)
Agonist
binds to a receptor and mimics the natural/typical action of a NT or other endogenous agent.
Antagonist
binds to the receptor and blocks or attenuates the natural response to NT or endogenous chemical
Partial agonist
binds the receptor, elicits some/sub-maximal response BUT, inherent binding may also block natural action of endogenous NTs/chemicals which can in the grand scheme… actually attenuates an agonistic response! this may be useful for over-active endogenous conditions of reducing side effects
Why should we care about drugs?
-impacts to tests to therapy!
-can alter exercise tolerance, diagnostic testing, falls, hypotension, diabetics
Adverse drug side effects
common, range from annoying to dangerous
-dizziness, drowsiness, weakness, low blood pressure, reduced/blunted HR, hypoglycemia, nausea, vomiting, diarrhea, constipation, etc
Patient management of adverse drug effects
dose timing, consideration of meal times, separating drugs from testing or therapy, use snacks, monitory HR/BP
Adverse drug-food interactions
common, impact absorption after PO dose - may be related to di/trivalent cations, pH, vitamins/cofactors or other chemical interactions
patient management of adverse drug-food interactions
separate drug dose from offending food/drink, some meds require reducing/eliminating or at least being consistent with certain foods/drinks
Metronidazole
an antibiotic that has a strong drug-food interaction with alcohol of any kind. alcohol including mouthwash, perfume, aftershave, etc.
Drug drug interactions
common, to mild, to life threatening
PD interactions
antagonistic effects, additive or synergistic effects (EX - BP/HR drops too low or stimulant with a sedative)
Chemical incompatibility interactions
predominately with parenteral agents, precipitates, Di/Tri-valent cations with some common oral meds, consult pharmacy!
PK interactions
ADME - especially drug metabolism in liver (cyp P450/clearance)
Old drug classification for pregnancy/lactating
A - human studies OK
B - Animal studies OK
C - animal studies MAY show harm, no human studies but benefit may outweigh risk
D - “Don’t”… evidence of human risk, may have benefit
X - evidence of human risk, benefits DON’T outweigh
updated drug classification for preg/lac
narrative
