Pharmacodynamics Flashcards
Pharmacodynamics defination ??
128
it is the branch of pharmacology which deals with biochemical and physiological effect of drug and M of action
specific mechanism of action of drug >
receptor mecha
enzyme mecha
ion channel mecha
carrier mecha
non-specific mechanism of drug ?
by physical means
by altering physio-chemical properties
by direct chemical alternation
G protein couple receptor example ?
muscarinic
adrenoceptors
dopaminergic
opioid
neuropeptide
molecular targets of drug action ?
receptors
enzymes
ion channels
carrier
plasma protein
structural protein
129
Receptor defination?
specialized target macro-molecules
to which drugs bind
and initiate events
leadiing to
alternation in biochemical/biophysical activity of cell
and consequently the function of the organ
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Classical receptors types ?
type 1 = ligand gated ion channel
2 = G protein coupled receptor
3 = receptor kinase
4 = nuclear receptor
130
Ligang gated ion channels example ?
nicotinic Ach receptor
GABA
glutamate
5HT3 receptor
Receptor kinase example ?
isnulin
Growth fac tors
cytokine receptor
nuclear receptor example ?
steroid
V-D
retinoic acid
thyroid hormone
131
Classification of G protein coupled receptor ?
Gs - stimulatory
Gi - inhibitory
Gq
G olf - olfactory
G t - photon -
Gs example ?
beta-adrenergic
hitamine
serotonin
Gi example ?
alpha adrenergic
Ach
opoid
serotonin
Gq example ?
Ach
bombesin
serotonin
Golf ?
olfactory epithelium
G t ?
photon
rhodopsin and color opsins in retinal rod and cone cells
post receptor events of ion channel receptor ?
opening of ion channel
closing of ion chnne;
post receptor events of G protein couple ?
formation of 2nd messenger
inhibition of 2nd messenger
Ca release
2nd messengers example ?
diacyl glycerol = DAG
cycline adenosine monophosphate = cAMP
cycline guanosine monophosphate = cGMP
inositol triphosphate = IP3
Ca ion
which drugs act by bloking K channel ?
anti-arrhythmatic drug
amiodarone
sotalol
which drug block Ca channel ?
Anti-HTN
captopril
verapamil
Open Cl channel ?
BDZ
barbiturates
post receptor events of tyrosine kinase receptor ?
phosphorylation of protein
post receptor evnts of DNa couple receptor ?
gene transcription
which drugs block Na chnnel ?
lidocaine
phenytoin
carbamazepine
quinidine
procainamide
receptor regulation type ?
up
&
down regulation
Receptor Up VS Down regulation ???/
135
withdrawal symotoms where ?
up-regualtion
up-regulation e receptor kar sathe prolong exposure e ??????
antagonists
down-regulation e kar sathe exposyure ?
agonist
up-regulation result ?
receptor inc
dec degradation of receptor
inc sensitization of receptor to agonist
result of down regulation ?
internationalization of the receptor
dec synthesis & inc destruction of receptos
Mechanism of action of Ion channel couple receptor ????
135+136
example of ICCR M/A ?
136
M/A of G protein couple receptor ?
136
tyrosine kinase receptor example ?
Insulin
GF
cytokine receptor
PDGF
EGF
ANP
TGF- beta
M/A of tyrosine kinase receptor ?
137
M/A of DNA coupled receptor ?
138
Affinity defiantion ?
tendency of a drug to bind with its receptor
Potency defination ?
it is ameasure of the amount of drug necessary to produce an effect of a given magnitude
Efficacy defination ?
it is an inherent property of an agonist to illicit a physiological response when it interacts with a receptors
147
Agonist definition ?
if a drug binds to a receptor and produce biologic response that mimics the response to the endogenous ligand
antagonist defination ?
A bind to the receptor bt do not initiate a response
no efficacy
149
partial agonist def ?
the drug that combines with its specific receptor
and evokes weak response
also prevents
agonits from acting on the receptor
partial agonists example ?
pindolol
ISA+++++++++=
150
Inverse agonist def ?
if a drug activates a receptor to produce effects that are specifically opposite to those of the agonits
example of inverse agonist ?
BDZ
beta-carboline
dose response relationship type ?
1.graded dose-r relationship
2.quantal dose -r relationship
graded dose-r r types ?
arithmetic form
log scale form
Dose-response curve ki ?
the graphical representation of conc of drug & response is called –
Shape of log scale form of graded-dose r r ?
sigmoid shape
hyperbola shape which one >
arithmatic form
144
quantal dose-response r shape ?
sigmoid
Therapeutic index defination ?
it is defined as the ratio of the median toxic dose -TD50 to the median effective dose ED50
TI equation?
TI = TD50//ED50
what is TI=1 ?
Poison
what is quantal -dose r curve ?
a graph of the fraction of a population that shows a specified response at progressively inc doses
145
TI dec hole ki hobe ?
caution nite hobe
what is the A/E of using low TI drugs ?
inc risk of A/E
drugs should be used with caution
plasma conc of drugs need to be monitored to avoid toxicities
154
Low TI drugs ?>
barbiturates
anti-convulsant s
anti-coagulant s
anti-HTN
anti-cancer
aminoglycoside
streoids
quinidine
cardiac glycosides
what if TI > 1 ?
drug safe
high TI antibiotics >
penicillin
sulfonamide
high TI BDZ >
diazepam’
clonazepam
154
other drugs with High TI ?
NSAID-paracetamol
diuretics-thiazide
phenytoin
154
therapeutic window ?
minimum toxic dose - minimum therapeutic dose
154
which one is more in TW ?
index of safety
reliability
TI vs TW ??
155
drug interaction defination ?
it is a phenomenon which occurs when the effectors of one drug are modified by the prior / concurrent administration of another drug
162
importance of graded dose -response relationship curve ?
for calculation ED50 LD50
study of agonistb & antagonists
to compare efficacy and affinity of drug
145
important of quantal dose relationship cruve ?
TI
ED50
TD50
LD50= median lethal dose
potency
drug interaction in receptor level ?
+ interaction
- interaction
+ interaction type ?
summation
potentiation
+ interaction other name >
synergism
summation def ?
2 drug effect = effect of individual dose
2+2=4
- interaction other name >
drug antagonism
165
potentiation ?
2+2>4
summation example >
amlodipine + atenolol = anti-HTN
aspirine + paracetamol = ana;gesia
potentiation example ?
levodopa + cabidopa
sulfamethoxazole + trimethroprim = co-trimoxazole
Drug antagonism defination >
when the effect of one drug is reduced / abolished by the presence of another drug
classification of drug antagomism ?
receptor mediated
-physiological
-pharmacological
non-receptor mediatred
-physical
-chemical
chemical antagonism example ?
gastric acid / HCl + antacid = chemical neutrilization = no HCl induced PUD
Physiological antagonism ?
when one drug antagonizes the action of another drug by acting on 2 different types of receptors
physical antagonism ?m
charcoal absorbd=s alkaloids
prevent absoprtion
used in alkaloid poisoning
physiological antagonism example >
Ach + M2 = bronchoconstriction
Adrenaline + beta-2 = bronchodialtion
when acting on 2 same receptor >
pharmacological anatgonism
166
non-competitive pharmacologic?
verapamil
nifedipine
prevent Ca influx through the cell ,membrane
example of pharmacological natagonism <
adrenaline + propranolol / phenoxybenzamine = antagonism
ADR def >
exam er age must
170
type-A augmented >?
toxic side effect
pharmacological side effect
secondary effect
excessive Therapeutic effect
type-B / bizarre ?
hypersensitivity
idiosyncracy
physiological vs pharmacological ?
167
type-c chronic >
isoniazid neuropathy
analgesic neuropathy
levodopa-dyskinesia
type-D - delayed <
carcinogenesis
teratogenesis
type-E ?
withdrawal reaction s
idiosyncracy vs hypersensitivity?
179
idiosyncracy def >
inherent
qualitative
abnormal
reaction to a drug
due to
genetic abnormality
179h
hypersensitidhypersensitivity ef ?
inappropriate /excessive immune response to an antigenic stimulus in a pre-sensitized host leading to tissue damage
which antagonism is reversible ?
physiological
antagonists example
bhujai bolo
muscarinic receptor
atropine tropamide
H2
ranitidine cimetidine
agonist example >
beta adrenoceptor - salbutamol;
muscarinic recptor - pilocarpine
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8.25PM
