Module 1 Flashcards
(107 cards)
Pharmacokinetics
movement of drug through body (what body does to the drug)
absorption, distribution, metabolism, excretion
MEC, steady state, duration of action
Pharmacodynamics
study of the effects of the drug (what drug does to the body)
receptor binding, post receptor effects, chemical reaction
Minimum Effective Concentration (MEC)
the minimum amount of drug required to work (to produce intended effect)
Absorption
movement of drug into the bloodstream
• passive transport (diffusion, facilitated diffusion)
• active transport (requires energy and enzyme)
• pinocytosis (cell carries drug across membrane by engulfing drug particles)
factors affecting absorption are blood circulation, pain, stress, food texture/fat content/temp, pH, route of administration
First Pass Effect (Absorption)
how much of the drug is metabolized in liver after passing through GI tract via hepatic vein
ingestion, absorption into small intestine, portal circulation through portal vein to liver, metabolism, reduced bioavailability with PO MEDS
Bioavailability
percentage of drug in the bloodstream after first pass effect
IV push= 100%
Distribution
distribution of the drug into the tissues
the drug is exiting the vascular system and being deposited to the tissues
consider transfer through capillary beds, placenta, blood brain barrier (BBB) aka permeability of cell membrane and circulation, etc.
protein binding (albumin)
Metabolism (Biotransformation)
how the body chemically modifies drugs into what can be excreted (P40 liver system)
consider liver function because it’s the main metabolism organ; liver lab values as well as age (infants and elderly)
therapeutic consequences: accelerated renal drug exertion, increased therapeutic action, activation of prodrugs, increased/decreased toxicity
Excretion
removal of the drug from the body (GI, kidneys, lungs, breast milk, saliva, hair, sweat, bile)
consider kidney function because it’s the main excretion organ; GFR, creatinine, BUN
first pass loss, half life
Half-Life
the time it takes for half the drug to be eliminated
if a drug has a short half life, that means it leaves the body quickly/higher risk of dependency and lower risk for toxicity…long half life means it leaves the body slowly/lower risk for dependency and higher risk for toxicity…CONSIDER DOSING
single dose time course determined by metabolism and excretion, repeated doses to achieve plateau drug lvls (takes time to plateau); LOADING DOSE VS MAINTENANCE DOSE
Therapeutic Index (TI)
a way to monitor the concentration of certain drugs is through obtaining a peak (highest concentration of drug in blood; most active) and a trough (lowest concentration of drug in blood; usually measured before next dose) level (”titers”, “serum drug levels”)
RATIO BETWEEN MTC AND MEC
some drugs have a narrow TI and need close monitoring of these lvls, high TI means drug is safer
Onset
when drug starts to have effects
Peak
what time is highest concentration of drug in bloodstream
Duration
how long drug effects lasts (therapeutic effects)
Receptor Theory
the proteins bind to receptors and tell the cells to activate or inactivate to produce or block a response
Agonist
turns on receptors
partial agonist lower affect than full agonist
Antagonist
blocks receptors
non-receptor responses: no use receptors
Non-Specific
one type of receptor at multiple sites
Non-Selective
multiple types of receptors anywhere in the body
Pharmacogenetics
the study of genetic factors influencing individual drug response
Focus of Pharmacogenetic Testing
look at specific DNA segments that play a role in the body’s response to a drug
Benefits of Pharmacogenetic Testing
- individualized treatment regimen
- decreases drug reactions and treatment failures
- promotes drug adherence
- reduces healthcare costs
- improve quality outcomes
- predict pt response to drug therapy
Interpatient Variability in Drug Responses (Pharmacodynamics)
measurement of inpatient variability; the ED50 vs LD50 (TI is ratio between these and can overlap between the curve for what is effective and what is lethal)
Additive
sum of effects of 2 drugs; increased effects