General Principles of Pharmacology part 3 Flashcards
define biotransformation
change in chemical structure caused by living system
another name for biotransformation
drug metabolism
what is the produce of biotransformation called
metabolite
where does biotransformation primarily occur
liver
produrg
activate an inactive drug
general characteristic of metabolite
more pole
more water soluble
excreted faster than parent drug
what are 4 results of biotransformation
produg
inactivate an active drug (main)
active drug to active metabolite
active drug/metabolite to toxic metabolite
what are 2 general classes of biotransformation reactions, generally what do they do
Phase 1 - add Hydrogen or Oxygen
Phase 2 - add cofactor
what reactions occur in phase 1
oxidation
reduction
hydrolysis
what reactions occur in phase 2
conjugation or synthesis
location of microsomal enzymes
smooth endoplasmic reticulum
microsomal enzymes are oxidative enzymes are also known as
mixed function oxidases (MFO)
P450 (CYP)
CYP cytochrome P450 ezymes are what type of oxidase
terminal oxidase
for microsomal enzymes, what characteristic must the substrate have
lipophillic
microsomal enzymes have what kind of acitivity
inducible
genetic polymorphism
genes can be different for people
where are nonmicrosomal enzymes located
cytosol
mitochondria
blood (esterases)
are nonmicrosomal enzymes induciable
generaally not
name 6 factors that affect rate of biotransformation
enzyme activity inducers/inhibitors age liver nutritional genetics gender
name 2 primary routes of drug excretion
biliary
renal
name secondary routes of excretion
sweat, saliva, breast milk, exhalation
define drug elimination
drug is no longer able to produce a pharmacological effect and can include excretion
where does central vein blood go from liver
general circulation
where are 2 places drugs can go from portal vein in liver
bile canaliculus
central vein
drugs that go through bile canaliculus in liver go where
small intestines
drugs going from bile canaliculus to S.I., have what characteristics
increase molecular weight
explain enteroheptatic cycling
Bile canaliculus
Small intestines
portal system - lipophilic
back to liver
what does enterheptatic cycling do to drug
prolongs interaction of drug
the amount of drug filtered in glomerular kidney depends on what
filteration rate
molecular rate
degree of binding to plasma protein
can weak acids and weak bases be filtered in glomerular kidne
yes
what are the 2 bidirectional transport systems for drugs in proximal nephron
anionic form
cationic form
prominent direction in proximal portion of nephron
peritubular fluid into proximal tubular cells then in lumen
how should drugs be administered to infants due to the proximal nephron
modified dosage
anionic and cationic transport system not fully developmed
what type of transport occurs in proximal tubule of nephron
active
distal nephron: amount of unionized drug that undergoes non-ionic back diffusion is dependent on
P.C.
equilibrium constant
[H+] of tube and luminal fluid
urine flow rate
what is the exchange of H and Na in distal tubule
H in (makes urine acidic) Na out
When H enter distal tubule what does it do to the weak acid? then what process does it do
it unionized weak acid
non-ionic back diffusion
When H enter distal tubule what does it do to the weak bases?
it ionizes weak bases
