6/10 Intro To PD Flashcards
Drug define
A chemical substance of known structure, other than a nutrient or essential dietary ingredient, which, when administered to a living organism, produces a biological effect
Pharmacodynamic
Effect of drug on the body
Pharmacokinetic
Effect of body on drug
Main types of drug targets
Carrier molecules / transporters
Enzymes
Ion channels
Receptors
Define pro drug
Biologically inactive compound which can be metabolised in the body to produce a drug
Types of enzymes
Inhibitor, false substrate, pro-drug
Ion channels
Protein molecules that span across the cell membrane allowing the passage of ions from one side of membrane to other side
Drug that binds to receptor and blocks the effect of endogenous chemical mediator
Antagonist
Agonist
Drug that finds to the receptor and generates an effect
Fastest receptor
Ligand-gated ion channels
Milliseconds
G- protein coupled receptors
Time scale and example
Time = seconds
Example = muscarinic, ACh receptor
Kinase- linked receptors
Time scale and example
Time = hours
Cytokine receptors
Nuclear receptors
Time scale and example
Hours
Oestrogen receptor
Ligand-gated ion channel receptors
Time scale and example
Time-milisecond
Example = nicotinic, ACh receptor
What cellular responses do nuclear receptors regulate?
Responses to hormones such as vitamin D3
Advantage of drug to have high specificity for its target?
Because it reduces the incidence of side effect
- if drug binds non-specifically to lots of different targets, it can have lots of different effects
Define affinity
How avidly a drug binds to its target site
Define efficacy
The drugs ability to activate the receptor once it has bound to it
Law of mass action
States the rate of a chemical reaction is proportional to the product of the concentrations of the reactants
High concentration of drug means it has Lower affinity why? Law of mass
Because system in equilibrium- adding more drug pushes equilibrium over to the right, producing more drug-receptor complex
How to study the relation between drug concentration and effect can be studied by using?
A relevant bioassay
e.g. Organ bath
Define potency
Measure of drug activity expressed in terms of the amount required to produce an effect of given intensity
Measure of efficacy
E MAX
Measure of potency
EC50