Quantitative Pharmacodynamics Flashcards
(24 cards)
What is Pharmacodynamics ?
A study of what the drug does to the body
What is meany by Potency ?
The concentration of a drug needed to have a certain percentage effect
What is meant by Efficacy ?
The maximum response achievable (this can differ)
What is meant by Fractional Occupancy (f) ?
The fraction of total receptor that is bind w/Ligand
What is meant by the Kd of a drug ?
The concentration of ligand that results in half of receptors being occupied
What does a small Kd value tell you ?
- That the dug has a high affinity = easier for ligand to occupy receptor
What does a large Kd value tell you ?
- Drug has a low affinity = not easy for ligand to bind to receptor
Free energy is released upon ligand binding to receptor. TRUE or FALSE ?
TRUE
High affinity binding occurs when large amount of free energy is released upon ligand binding. TRUE or FALSE ?
TRUE
Total binding = specific binding + non-specific binding. TRUE or FALSE ?
TRUE
How is Kd measured ?
1) The ligand is labelled using a Radionuclide e.g: 3H.
2) Binding is then measured
What is meant biological effect ?
The response of a tissue to a drug
What is meant by EC50 ?
The concentration of a drug required to cause half the maximum effect
What is the role of a Partial Agonist ?
Fully occupies the receptor without activating the maximum response
What is meant by a Spare receptor ?
When an Agonist produces a max response without all the receptors being occupied
Spare receptor is also known as ‘Receptor reserve’
Beta blockers are often Beta adrenoceptor antagonists; e.g: Propanolol. TRUE or FALSE ?
TRUE
Pindolol and Rimonabant are exceptions beta blockers that act as Beta adrenoceptor antagonists. TRUE or FALSE ?
TRUE.
Pindolol act as a partial agonist
Rimonabant acts as an Inverse agonist
Isoprenaline is a full agonist that activates beta adrenergic receptors. TRUE or FALSE ?
TRUE
Prenalterol is a partial agonist that activates beta adrenergic receptors. TRUE or FALSE ?
TRUE
Properties of Agonists and Antagonists ?
- Reversible
- Non -covalent
- Competitive
- Specific and selective
What is an Irreversible Antagonist ?
An Antagonist binds to the same site as the agonist.
It does not dissociate – it binds covalently. e.g; Omeprazole
The effect of the competitive antagonist can be overcome with a higher concentration of agonist. TRUE or FALSE ?
TRUE
What is an Allosteric/Non-competitive Antagonist ?
Antagonist binds to a different site on the receptor, induces a conformational change therefore receptor cannot be activated by agonist
What is an Inverse agonist ?
Agonist that reduces the amount of receptor available to spontaneously activate itself.
It also reduces the resting response of a tissue.
