Potency And Efficacy

Efficacy measure the maximum pharmacologic effect produced by a given drug. EC50 of a drug is the concentration of the drug that produce 50% of maximum effect. The drugs with lower EC50 have more potency.


Competitive antagonists bind to receptors without producing biological effects. Increasing the concentration of agonists will reverse the effect of competitive antagonists. In contrast the effect of noncompetitive antagonists cannot be reversed by agonist

cAMP Dependent G-protein Coupled Receptors

G protein coupled transmembrane receptors is composed of 3 subunits; α, β and ϒ. When a ligand or a drug binds to g- protein receptors, the α subunit is activated and detached from the other subunits and binds to adenylyl cyclase enzyme. The active enzyme

Partial Agonists

Partial agonist when binds to empty or receptors occupied by full agonist they produce biological effect that is weaker than full agonists. So partial agonists are better that nothing when occupied to empty receptors but works more as antagonists when bin