Week 4 - Pharmacodyamics - Nichols

Question 1

A drug may increase of decrease cell function, but does NOT:

Answer 1

initiate new cellular function

Question 2

Important attributes of receptor-mediated processes:

Answer 2

• Compartmentalized
• Self-limiting on short time scales
• Organized in opposing systems
• Small signals can be amplified
• Large number of receptors operate through a small number of 2nd messenger systems

Question 3

Occupancy theory assumes that:

Answer 3

The response or effect, is proportional to the receptor occupancy.

And that each receptor only binds to one ligand!

Question 4

Explain affinity:

Answer 4

Ability to form complex with receptor. Greater affinity will lower the amount of drug required to produce effect.

The curve looks the same, but will shift toward the right with lower affinity

Question 5

What does potency mean with regard to the dose-response curve?

Answer 5

Potency is the relative position of the curve. Further to the left means that the drug is more potent

Question 6

Explain efficacy:

Answer 6

Capacity to produce the response

Full efficacy is alpha=1

Question 7

Difference between full and partial agonists?

Answer 7

Full agonist produces the maximal response and has full efficacy (alpha = 1)

Partial agonist produces a less-than maximal response. The alpha will be somewhere between 0 and 1.

Question 8

Pure antagonist is defined how?

Answer 8

Has affinity for the receptor and stops agonist from binding. At the same time has NO efficacy. alpha=0

Question 9

What will competitive and noncompetitive antagonists do to the dose response curve?

Answer 9

Competitive

• Shifts dose-response to the right
• Slope stays same
• Reversible
• Adding more drug will help recover activity

Non-competitive

• Irreversible
• slope reduced
• Vmax reduced
• Adding more drug will not recover activity

Question 10

Partial agonists are important why?

Answer 10

Turns out that in the presence of a full agonist, a partial agonist will e sort of an antiagonist, but not quite as bad because they still create an effect.

Question 11

Inverse agonists do what?

Answer 11

They can actually lower the activation of a recptor to BELOW basal levels. WHOA!

Question 12

Quantal dose effect:

Answer 12

Individuals can differ from the median effective dose of a drug. They can either be hyporeactive of hyperreactive

Question 13

What does the therapeutic index measure?

Answer 13

The relative safety

Difference between ED(effective dose) and LD(Lethal Dose).

Usually you want this margin to be very large. In extreme cases it is small and must be managed very careful for very serious disease.

Question 14

Imperfect selectivity of a drug to its particular receptor leads to what?

Answer 14

Drug side-effects.