Page 37 - Pharmacology Mnemonics and Short Notes

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Potency  amount required to produce required effect

The amount of drug needed to produce a given effect
Determined by

 Affinity of the receptor for drug

 No of receptor available

 can be determined by quantal and graded dose response curve

Spare receptors

Spare receptors are present if maximum response is obtained at less than
100% occupation of the receptors

Reasons

 Duration of activation of receptor may be greater than the duration
of Drug receptor interaction

 Actual no of receptor may exceeds the no of effectors

 Spare receptors increase the sensitivity of the receptors to the
agonist

Therapeutic Index
This is the ratio of: LD 50

ED 50

 It measures margin of Safety for a drug.

Contents

Pharmacology Mnemonics and Short Notes By Muhammad Ramzan Ul Rehman