How drugs work class week 2 notes
Drug is absorbed then liver filters out toxins and metabolized. The kidneys excrete drug.
PHARMACOKINETICS: How drugs work in the body
1. Absorption first step
2. distribution- metabolism
3. excretion/elimination
when a drug is absorbed intracellular fluid is about 2/3 of fluid space is inside cell
1/3 is outside cell. (extracellular fluid)
1. Plasma
2. intestinal fluid
3. intercellular fluid
4. transcellular fluid
5.fat
Plasma protein binding (ppb)
Acidic drugs bind to plasma albumin and basic drugs to a a1-glycoprotein
Anticholinergic- atropine- opposite if acid choline, atropine stored in eye, makes heart rate go up
and eyes dilate
Acid choline –major neurotransmitter for- parasympathetic system- rest relaxation- non-flight or
fight, digestion
Metabolism
Hydrophilic drugs like urine, go to urine and don’t change in the process, they are also not seen
as toxic to the body.
Primary site for metabolism liver- filters out toxins
Kidney, lungs and plasma are other places where metabolism can be held
Inactivation is done in metabolism
Metabolism has 2 phases
Phase 1 non synthetic reactions- mobilization through oxidation
Cytochrome (CYP 3A4/5) – An enzyme of metabolism (half drugs are metabolized by this)
b. reduction next
c. hydrolysis
d. cyclization
e. DEcyclization
phase 2 synthetic (conjunction)
uses energy to metabolize drugs in this phase
any drug injected is parental
oral drug have higher doses in general due to the processes it has to go through and pass effects
excretion goes out through urine, bile, feces, exhaled air, saliva, sweat, milk, skin
Hydrophilic/ polar goes through urine
12/19/19
Drug affects
Nociceptors – pain
analgesics- decreases nociceptors
it takes a bit to get to respiratory depression which is what causes death in overdose
opioid
endogenous- internal –decreases sympathetic nervous system (why ppl need to use more and
more has body gets used to drug (need a higher dosage of drug to get high))- down grade of
receptors
morphine- narcotic that is injectable
codeine- oral – 50% bioavailable huge first past metabolism (metabolism happening in GI Tract
and liver) before absorption
Fentanyl- injectable, transdermal (through skin) absorbed into the blood stream this way. lipid
solubility is high.
heroin (diamorphine) (sister drug to morphine, more affinity for receptors) injectable, 1.5-2 times
more potent than morphine
fentanyl- tiny dose gets huge affect
1. Agonist-2. receptor-3. intrinsic response-4. change in cell membrane gradient
1. Antagonist- 2. binds to receptors – x intrinsic response (stays in the way)
in class:1/7/2020
Naltrexone: opioid/antagonist
(Vivitrol)
camprol- GABA agonist
Antabuse-blocks aldehyde, dehydrogenase
suboxone- buprenorphine=opioid partial agonist + naloxone= opioid antagonist
buprenorphine- blocks pain from narcotics (stops with drawl symptoms) naloxone is to stop
overdose
Antabuse- can treat alcohol abuse any small consumption of alcohol can cause unpleasant
reactions to medication
camprol- is used to treat alcohol abuse –balances out chemicals in brain to remain equilibrium
week 5 drug tolerance/dependence
has psychological effects
drugs have effects on other parts if the body
antidepressant drug- not an immediate drug (some up to 4 weeks) the safer drugs takes longer to
feel relief from the drug
they are huge first pass drug- why it takes so long
*cytochrome p450*-enzyme that detoxifies ionizes
TCA antidepressant drugs
tranquilizers-major/minor
phenothiazine – major
peperzine
minor – anti-anxiety drug not used as anesthesia
Analgesic- pain killer
Gaba inhibitory- inhibits cell membrane
narcotics are analgesic