Drug Receptor Interaction. Flashcards
What are the strongest bonds that can be formed between drugs and their receptors?
Covalent bonds.
What are the weakest bonds that can be formed between drugs and their receptors?
Hydrophobic interactions.
What is drug binding?
When the drug binds to a receptor.
What is meant when it is said that drug binding is reciprocal?
That certain drugs can only bind to certain receptors.
How does the strength of the bond between the drug and receptor affect the activity of the drug?
The stronger the bond, the longer the drug is bound to the receptor and this means the drug will be active for longer.
Will all receptors be able to interact with all drugs?
No, individual receptors will only recognise certain classes of drugs.
What factor about receptor binding will lead to a strong effect from the drug?
The better the fit between the drug and receptor means the stronger the effect of the drug.
Why is the structure of the drug very important?
As the better the drug fits into the receptor, the stronger the drugs effect on the receptor.
What dictates the tightness of the binding between the drug and the receptor?
The type of bonds that are formed between the drug and the receptor.
How does the strength of receptor binding affect a drugs duration of action?
The stronger the binding the, the longer the therapeutic effect.
What is drug affinity?
The strength of attraction between a drug and a binding site.
What kind of drug affinity will lead to short term binding?
Weak affinity.
What kind of drug affinity will lead to long term binding?
Strong affinity.
Does the affinity of a drug dictate the strength of the bodies response?
No, the affinity of the drug does not dictate the strength of the response.
I.e. a drug could have a low affinity by deliver a very large response.
What do we use to measure drug affinity?
The KD constant.
How do we use the KD constant to measure affinity?
The lower the KD, the higher the affinity.
What is the KD constant that we use to measure affinity?
The point when 50% of the targets are occupied by the drug.
What is the efficacy of a drug?
How strong the effect of the drug is.
What effect are we always trying to achieve with a drug?
The maximum effect.
What will be the characteristics of drugs with very strong efficacy?
A maximum effect, irregardless of dose.
What characterises drugs with high potency?
They have a high affinity for receptors, even at low concentrations.
What is used to compare different drugs within the same class?
Drug potency.
Drugs with high potency will have what characteristic?
The higher the potency of the drug the higher the affinity to the receptor.
How do we measure drug potency?
By using the EC-50 which is the concentration that leads to 50% of the maximum effect.
What is binding selectivity?
The different affinities that drugs will have for different receptors.
What is binding specificity?
The specific receptors that a drug will bind too.
Will drugs bind to receptors regardless of the concentration of the drug?
No, some drugs will only bind to certain receptors at secific concentrations.
E.g. A certain drug may bind to histamine receptors at low concentrations, but at higher concentrations it may bind to histamine and monoamine receptors.
If drug A is more potent than drug B should we give a larger or smaller dose of drug A to achieve the same effect?
If a drug is more potent we can give less of that drug as only a small amount is needed to bind to all of the receptors.
E.g. We need much more of drug B to achieve the same effect as drug A.
If drug A is more potent than drug B will it be placed on the left or right of drug B in a graph?
A drug that has a higher potency will be placed to the left of a drug with lower potency as it achieves the same effects at a lower concentration.
Do we need a small or large dose of a drug if it is very potent?
We need a smaller concentration a very potent drug to get the full effect of the drug.
If drug B is less potent than drug A will it be placed on the left or right of drug A in a graph?
A less potent drug is placed to the right of a more potent drug on the graph.
What is a drugs EC-50?
50% of the drugs maximum response.
Can drugs with different potencies have the same EC-50?
Yes, as they can achieve their maximum response at different concentrations.
What can we learn about a drug if we know its EC-50?
How potent a drug is and what its efficacy is.
