Pharm Topic 6: General Mechanisms Of Drug Action

Front 1

Graded vs quantal dose responses

Back 1

Graded have increasing response with increasing [], quantal are all or none.

Front 2

Affinity vs Efficacy

Back 2

Affinity - How well the drug sticks to its receptor
Efficacy - How well the drug starts its signal transduction pathway.

Front 3

Drug efficacy and what factors determine it

Back 3

Also known as Emax, is the maximum response achieved by an agonist.
1) Type of interaction w/ receptor (agonist vs partial agonist)
2) Characteristics of effector system involved.
3) Limitations on the amount that can be administered.

Front 4

Drug potency and what factors determine it

Back 4

A comparison of the size of a dose needed to produce a certain effect. The lower the dose the greater the potency.
1) Affinity for its receptor
2) Efficiency of transduction step.
3) Ability of a drug to reach its site of action.

Front 5

ED 50

Back 5

Dose required to get desired effect in 50 % of people

Front 6

Partial agonist

Back 6

Even at highest [] only gives a partial response. Can actually act as an antagonist to more efficacious drugs.

Front 7

Therapeutic index

Back 7

LD 50 / ED 50 (larger the better)

Front 8

Margin of safety

Back 8

LD 1 / ED 99 (Larger the better)

Front 9

Ways we can target enzymes without causing ourselves harm

Back 9

1) Target an enzyme we dont have
2) We have a different isoform for the enzyme targeted and the therapeutic dose is much lower than a dose which would harm our enzymes
3) Incoorperation model where the desired target incooperates the molecule at a much higher rate than healthy cells (ex. cancer).
4) Target an enzyme which is specific to only certain cells.

Front 10

Gi, Gs, Gq

Back 10

Gi - Inhibition of cyclic AMP (inhibits adenyl cyclase)
Gs - Activates adenyl cyclase
Gq - Couples to phospholipase C > DAG and IP3. IP3> calcium signal.

Front 11

Non-competitive antagonist

Back 11

Drug binds actrive site or allosteric site with extreme affinity or covalent bonds. Antagonist action only terminated when receptor is degraded.

Front 12

What types of drugs work via neither the receptor nor proteins

Back 12

1) Lipid soluable anesthetics (inert gas, NO, chloroform).
2) Osmotic Diuretics
3) Osmotic Cathartics (same as diuretics but for the bowels)
4) Antacid Drugs
5) Chelating agents