Partial agonists

Definition

Partial agonists are drugs that bind to and activate a receptor but produce a smaller effect compared to a full agonist. They can act as both agonists and antagonists depending on the presence of other substances.

5 Must Know Facts For Your Next Test

1. Partial agonists have intrinsic activity but less than that of full agonists.
2. They can compete with full agonists for receptor sites, thereby reducing the overall effect.
3. Used therapeutically to balance efficacy and side effects by providing moderate stimulation.
4. Their dual role makes them useful in treating conditions like addiction and anxiety.
5. Can exhibit a ceiling effect, where increasing dosage does not increase the response.

Review Questions

• What is the primary difference between partial and full agonists?
• How can partial agonists act as both agonists and antagonists?
• Why might partial agonists be preferred in some therapeutic scenarios over full agonists?

Related terms

Full Agonist:

A drug that fully activates the receptor it binds to, producing maximum biological response.

Antagonist:

A substance that binds to a receptor but does not activate it, blocking the action of other drugs or endogenous ligands.

Intrinsic Activity: The relative ability of a drug-receptor complex to produce a maximum functional response.