The ratio of the dose that produces toxicity to the dose that produces a clinically desired or effective response in a population of individual is Known as
(Therapeutic Index) (55- KDT6th) (32-33-LP3rd)Therapeutic Index - The therapeutic index of a drug is ratio of the dose that produces toxicity to the dose that produces a clinically desired or effective response in a population of individuals* A drug may be capable of inducing a higher therapeutic response (have higher efficacy) but development of intolerable adverse effects may preclude use of higher doses eg prednisolone in bronchial asthma* The therapeutic index is thus measure of a drug's safety*Therapeutic Index =LD50(Median lethal dose)----------------ED50(Median effective dose)* Warfarin - anticoagulant with a small therapeutic index* Penicilline - antimicrobial with a large therapeutic indexPotency - a measure of the amount of drug necessary to produce an effect of a given magnitude.* For a number of reasons, the concentration producing an effect that is 50% of the maximum is used to determine potency i.e. (EC50)* EC50 is the concentration of the dnig that produces a response equal to fifty percent of the maximal responseEfficacy - is dependent on the number of drug- receptor complexes formed and the efficiency of coupling of receptor activation to cellular responses (Emax)* Efficacy is more important than potency* A drug with greater efficacy is more therapeutically beneficial than one that is more potent* Small the EC50 the more potent the drug
Efficacy
Potency
Therapeutic index
Partial agonist
General Pharmacology