Agonists

Question 1

What is an agonist?

Answer 1

An agonist binds to a receptor and produces a biologic response. An agonist may mimic the response of endogenous ligand or it may elicit a different response.

Question 2

What is a full agonist?

Answer 2

If a drug binds to a receptor and produces a maximal biologic response that mimics the response to the endogenous ligand, it is known as a full agonist.

Question 3

What is a partial agonist?

Answer 3

Partial agonists have efficacies (intrinsic activity) greater than 0 but less than a full agonist. Even if all the receptors are occupied, partial agonist can’t produce an Emax of as great a magnitude as that of a full agonist.

Question 4

What is an inverse agonist?

Answer 4

Inverse agonists stabilize the inactive form of the receptor. All of the active receptors are forced into the inactive state. They reverse the constitute activity of receptors and exert the opposite pharmacologic effect of receptor agonists.