Week 2 Flashcards
pharmacology
how drug affects body & body’s response to drug
pharmadynamics
what drugs does to body
pharmacokinetics
what body does to drug
pharmacogenetics
how genetics influence drug response
pharmacotherapeutics
drug choices for treatment / prevention
toxicology
body’s response to harmful effects of drugs
binding types
agonists, competitive & non-competitive antagonists, allosteric activator
agonists
activates receptor for effect
competitive antagonist
competes with agonists to bind to receptor binding site
non-competitive antagonist
binds to other receptor site that affects main binding site
allosteric activator
binds to other receptor site that enhances main receptor binding site
principles of pharmacokinetics
MADE = metabolism, absorption, distribution, excretion
metabolism
drug transformation of drug into hydrophilic form for kidney elimination
where does metabolism mainly occur
liver
enzymatic phases of metabolism
phase 1 = functionalization / catabolism
phase 2 = conjugation / anabolism
what does functionalization mainly involve
cytochrome P450 group of enzymes
CYP enzymes are ___ - containing enzymes
heme
most common CYP
CYP 3A4
alcohol is metabolized by __
CYP 2E1
CYP inducer example
rifampicin
CYP inhibitor example
fluconazole
CYP substrate example
warfarin
what does conjugation involve
adds molecule to increase hydrophilicity via
- methylation
- acetylation
- glucuronidation
- sulphation
absorption
% of drug that remains unchanged entering systemic circulation via plasma administration
why is oral administration not 100%
incomplete absorption across gutwall / first-pass elimination by liver
oral administration is mainly absorbed in __
ileum
absorption modes
- facilitated passive diffusion
- active transport
- passive diffusion
distribution
amount of drug in relation to concentration in plasma/body
Vd formula
amount of drug in body / plasma concentration
high Vd =
exceeds bodyweight
low Vd =
value close to blood volume (5L)
Can Vd exceed physical volume of body
yes
major compartments of distribution
- plasma (5%)
- interstitial fluid (16%)
- intracellular fluid (35%)
- transcellular fluid (2%)
- fat (20%)
lipid insoluble drugs mainly confined to __
plasma & interstitial fluid
excretion
drug eliminated from kidneys into urine
if patient have defective kidneys, how should you change your drugs
reduce dose / switch to alternative agents
main excretory routes are __
kidneys, hepatobillary, lungs
clearance is fundamental ___ parameter for drug elimination
pharmacokinetic
what factors are involved in dose planning
concentration, intervals, route of administration
what does dose planning determine
therapeutic index for safe drug testing
when is monitoring needed
for narrow therapeutic index drugs
half-life
time for drug concentration reduced by 1/2
decreased T1/2 = increased ___
drug clearance & dosing intervals
an ideal therapeutic dose has __ efficacy, ___ toxicity
high; low
where is the therapeutic index
between ED50 & TD50
ED50
median effective dose
TD50
median toxic dose
what causes drug response variations
- different drug concentration reaching receptor site
- different endogenous receptor ligand concentration
- altered receptor function
- changes in downstream response to receptor binding
tachyphylaxis
sudden desensitization to drug
adverse drug effects
hypersensitivity, idiosyncratic, iatrogenic, teratogenic
hypersensitivity
allergies
idiosyncratic
unusual response to drug
iatrogenic
negative effect of drug
teratogenic
harmful to fetus
drug interactions
ASAP
additive, synergistic, antagonist, potentiation
drug administration methods
instillation
inhaler
sublingual
transdermal
suppository
topical
subcutaneous
intravenous
intramuscular
instillation occurs at
ophthalmic (eyes), ears, intranasal
where does intramuscular injection occur at
deltoid, vastus lateralis, gluteus maximus
most rapid onset of drug administration
intravenous
parenteral
any drug administration which involves using a needle
parenteral examples
intravenous, intramuscular, subcutaneous, intraosseous, epidural, intradermal
what CYP is important for clopidogrel
CYP2C19
variants of CYP 2C19
*1 = normal
*2 - *8 = no / reduced enzyme
*17 = increased activity
why are some medications taken after food
increases bioavailability & pH adjusted when digesting food
a drug with a low Vd tends to remain in ___
plasma
a drug with high Vd means __
more distribution to other tissues
