VM 704- (Physiology) Introduction to Pharmacology

What is the definition of pharmacodynamics?

The study of the action of a drug on living tissue (Receptor binding, signal transduction, etc.)

What is the definition of pharmacokinetics?

Drug absorption, drug distribution, drug metabolism, drug excretion

What is the definition of pharmacotherapeutics

The study of the use of drugs in treating disease (clinical applications)

What is the definition of pharmacy?

The science of preparing, dispensing, and handling medications

What is the definition of posology?

The study of the amount of drug required to produce therapeutic effects

What is the definition of a drug?

Any endogenous or exogenous chemical that causes a physiological or pharmacological effect.

What is the equation for the dissociation constant (affinity)?

K_d = [D][R] / [D * R]

What does it mean if a drug has a lower K_d value?

It has a HIGHER affinity.

What is the DEFINITION of K_d?

The amount of a drug that it takes to do [something].

What are the 3 main types of drug-receptor bonds?

1. Covalent

2. Electrostatic

3. Hydrophobic

What are the 3 kinds of bonds are included in the category of electrostatic bonds?

1. Ionic

2. Hydrogen

3. Van der Waals

What is the definition for the NUMBER value of K_d?

The amount of a drug needed to occupy 50% of the receptors.

(FOR THE EXAM) Are K_d and EC₅₀ the same value?

NO

What does EC₅₀ measure?

Potency

What does E_max measure?

Efficacy

What do we call drugs that don’t reach 100% E_max?

Partial agonist

What do we call drugs that can reach 100% E_max?

Full agonist

What produces an effect after a drug is bound to its receptor?

Signal transduction

What are the 4 main types of receptors of drugs?

1. Ionotropic receptors (open ion channels)

2. Metabotropic receptors (G-protein coupled receptors)

3. Receptor tyrosine-kinases

4. Transcription factors

Where do the 4 main types of drug receptors reside?

On the postsynaptic membrane.

Which is more important: potency or efficacy?

Efficacy

What is the role of an agonist?

To bind to receptors and increase basal activity.

What is the role of an antagonist?

Bind to receptor with affinity but have no intrinsic activity.

What are the 2 main types of antagonists?

1. Competitive antagonist (bind to same receptor as agonist)

2. Non-competitive antagonist

What are the 2 types of non-competitive antagonists?

1. Allosteric (binds to a different receptor site)

2. Irreversible (binds covalently to SAME receptor site)

Is a competitive antagonist’s efficacy dependent on concentration?

Yes.

Is a non-competitive antagonist’s efficacy dependent on concentration?

No.

What does ED₅₀ measure?

The dose at which 50% of patients will respond.

What does LD₅₀ measure?

The dose at which 50% of patients die.

What is the equation for the therapeutic index of a drug?

LD₅₀ / ED₅₀

How can the downregulation of receptors occur?

By repeated overstimulation or prolonged stimulation of receptors.

How can the upregulation of receptors occur?

By repeated understimulation.