Pharmacodynamics Flashcards
What is the definition of pharmacodynamics?
Effects of drugs on the body
What is the difference between agonists and antagonists?
Agonists activate endogenous proteins
Antagonists block endogenous proteins
Where can drugs act?
Cell surface receptors, nuclear receptors, enzymes, ion channels, transporters
What is EC50?
Concentration of a drug that gives half of the maximal response
What is a partial agonist?
Drugs that bind to and activate a given receptor, but have only partial efficacy at the receptor relative to a full agonist
What is drug selectivity?
Describes how selective a drug is for its target and the chance it will interact with unwanted targets to give side effects
As an example, why does penicillin have very little side effects?
Mechanism of action - inhibits cell wall synthesis of bacteria
Mammalian cells do not have cell walls so cannot act on them
What is drug specificity?
Targeting specific receptors on specific organs
eg adrenergic receptors (heart b1 and lungs b2 - salbutamol example)
What is affinity?
Tendency of a drug to bind to a specific receptor type
When comparing two curves on a graph, which one has the highest affinity?
The curve most to the left
What is efficacy?
Ability of a drug to produce a response as a result of the receptor being occupied - maximum effect of a drug
What is potency?
Dose required to produced the desired response (the two different doses of two drugs required to have the exact same effect) - affinity + efficacy
What is the therapeutic index?
The relationshi between concentrations causing adverse effects and concentrations causing desirable effects
TI = EC50 (adverse effect) / EC50 (desired effect)
