Pharm Quiz 1

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Terms in this set (...)

Pharmacokinetics
the rate at which drug combinations accumulate in and are eliminated from the body
-what the body does to the drug
absorbed
distributed
metabolized
excreted
Route of absorption: enteral
oral p.o
sublingual s.l
rectal p.r
Route of absorption: parenteral
injection
-intramuscular IM
- intravenous IV
-Intrcoronary IC
-Intrathecal
-Intraarticular
-Subcutaneous sc or sq
inhalation
topical
transdermal
Absorption and distribution affected by:
route of administration
chemistry of drug
barriers (blood brain,placenta) to absorption vs. "carriers" to assist
Phase one Pharmacokinetics: Absorption
transfer of drug to circulation to allow for delivery to target tissue
cell membranes present barriers
-lipid soluble molecules cross easily via passive diffusion
-small H20 -soluble molecules cross via aqueous channels: passive diffusion
-some molecules need a carrier protein to assist via facilitated diffusion or active transport
Impact of chemical Make-up on absorption
-Needs to be h20 soluble to pass through GI tract
-Needs to be lipid soluble to pass through cell membranes
-passive diffusion is primary method for drugs to pass cell membranes
-lipid soluble -> increased cellular uptake
-non lipid soluble passes through without absorption
-H20 soluble -> decreased cellular uptake
- enteric coating-> slows absorption
SR (slow release)
Impact of exercise on drug absorption
-minimally studied
-route of administration- IM, SQ, transdermal, inhalation
-combination impact of exercise and drug induced vasodilation
notes: IM don't put an IM med on the muscle you are working on
Bioavailability
the percent of drug that gets into systemic circulation
ex- 1st pass (through liver)-> decreases available drug by 20%
Biotransformation
most drugs metabolized (transformed into less active compounds) by liver
check liver enzymes: ALT (SGPT), AST (SGOT), LDH, albumin
Liver damage: alters the amount of albumin available for binding
notes- makes it available to tissues once it moves through
Drug Elimination
most drugs are water soluble - excreted by kidneys
-renal function- creatinine clearance- (we need to know that the kidneys are working to see if meds are getting out of the body)
others excreted through
-biliary /fecal
-lungs
-exocrine
some are reabsorbed prior to excretion
Half life
amount of time required by the body to biotransform drug and to decrease concentration of drug by 50%
-implications for dosing intervals
-patient monitoring requirements
notes: drugs that are cleared by the kidneys are likely to have long half lifes
Drug steady state
takes 4-5 half life's to achieve steady state
Factors affecting pharmacokinetics
disease
age
genetics
gender
body comp
diet (food/drug interactions)
other chemicals (OTC, recreational, supplements, nicotine, caffeine, ETOH)
Physical factors
Pharmacodynamics
what does the drug do to the body?
Localized drug effects
drug applied to target area
minimal absorption through bloodstream
systemic drug effects
effects seem in many body systems
Agonist
-stimulates a receptor and enhances physiologic effects
-drug binds to preferred receptor site and produces changes. Get max response when all receptor sites are bound to agonist drug
Antagonist
Inhibits a receptor and decreases physiologic effects
-competes for receptor site with agonist. By blocking access to site, it decreases effect or prevents effect altogether
Dose response curve
threshold dose is the point at which some minimal effect can be noted
-ceiling effect/ maximal efficacy- point at which no further benefit is derived
notes: how much drug do they need to get an effect- how much can we give them without giving undo side effects
ceiling - max benefit we are going to get
dosing- so we ca take the least amount that we need
Cumulative Dose Response Curves
ED 50= Median effective Dose
TD 50= Median Toxic Dose
use this to get therapeutic index- we want it to be pretty wide
Drugs to treat clotting
anti platelet
thrombolytics
anticoagulants
Anti platelet
inhibit platelet aggregation and clotting
ex- aspirin, persantine, (dipyridamole)
ADP activator - plavix (clopidogrel)
Thrombolytics
tPa
Streptokinase
- clot dissolution
Anti- coagulants
Thrombin inhibitors; inhibit manufacture of thrombin and prevent influence of thrombin on fibrinogen
Ex- Heparins- Lovenox (enoxapaprin)= inactivated thrombin and factor xa, monitor PT/PTT
-Coumadin (warfarin) - inhibit clotting factors by impairing vitamin K function in liver, monitor INR and prothrombin time
Direct thrombin and factor Xa inhibitors
bind to thrombin and impact thrombins ability to activate fibrin
-Pradaza(dabiagtran)
-Xeralto (rivaroxaban)
-Eliquiis (apixaban)