Principles of Drug Action Flashcards
(28 cards)
define drug
chemical substance of known structure, other than a nutrient or essential dietary ingredient. produces biological effect when administered to living organism.
name a drug from genetic engineering
insulin
what type of drug are beta blockers, AT1, and receptor blockers?
synthetic chemicals
name the classes of drugs.
beta blockers, ACEI, AT1 (angiotensin II type 1) blockers, statins, NSAIDs, Anti histamines.
what drug class is used for allergies?
anti histamines
name the main kinds of regulatory proteins commonly involved as primary drug targets
receptors
enzymes
carrier molecules
ion channels
what are the substances which act on beta 1 adrenoceptors in the heart?
noradrenaline: activates receptor.
beta blockers (e.g. atenolol): block beta 1 (and or beta 2) adrenoceptors
what does activation of beta1 adrenoceptors of the heart entail?
increased heart rate and force of contraction. decreased duration of contraction and conduction time.
define agonist. give example.
when bound, the receptor becomes activated
morphine
define antagonist. give example.
blocker. binding does not lead to activation.
Beta blockers
define affinity
ability of a drug to bind to a receptor. “affinity” of drug for receptor.
what is the mass action equation describing?
simple bi molecular interaction between drug and receptor.
f = [D]/([D] + KD)
f = fraction of receptors occupied
[D] = concentration of drug (Molar)
KD = equilibrium dissociation constant of the drug for the receptor
what do beta2 and beta1 adrenoceptors do in the heart?
mediate powerful increases in contractile force, hasten relaxation.
define potency
a measure of a drug’s biological activity expressed in terms of the dose required to produce a pharmacological effect of given intensity.
-EC50 is the concentration of drug that causes 50% of the maximum effect of the drug
ability for noradrenaline and adrenaline to cause cardistimulant effects is determined by:
concentration
affinity
efficacy
define full agonist
agonist that produces maximal effect with respect to receptor, produce maximal effect by occupying less than 100% of receptors.
name a full agonist (with respective receptor)
noradrenaline at b1-adrenoceptors in human right ventricle
define partial agonist
produces submaximal effect with respect to that receptor, even when occupying 100% of receptors.
name a partial agonist (with respective receptor)
cyanopindolol, b3 adrenoceptors in rat colon
define efficacy
“strength” of agonist-receptor complex to evoke response.
(tendency of the drug-receptor complex to adopt active (AR*) rather than the resting (AR) state)
constitutive receptors are:
receptors that are active without an agonist.
what is the agonist that reduces the effects of constitutive agonists? (what are they called)
inverse agonists.
what is meant by reversal of efficacy? what principle is it from?
when two drugs A and B act differently for different effectors. (switch between full agonist and no effect)
biased agonism (ligand directed signalling)
what is the Schild plot?
The Schild equation describes the potency of a competitive antagonist in terms of its concentration and its ratio to the concentration of the agonist.
assess competitive nature of antagonists.
