Intrinsic activity

Definition

Intrinsic activity refers to the ability of a drug to activate a receptor and produce a maximal biological response. It is a measure of the efficacy of a drug-receptor complex.

5 Must Know Facts For Your Next Test

1. Intrinsic activity is independent of drug concentration; it measures the maximum effect achievable by the drug.
2. Drugs with high intrinsic activity are full agonists, while those with lower intrinsic activity are partial agonists.
3. Antagonists have zero intrinsic activity as they do not activate receptors but block them instead.
4. Intrinsic activity plays a crucial role in determining the therapeutic and side effect profiles of drugs used in treating diseases like Myasthenia Gravis and Alzheimer’s Disease.
5. Understanding intrinsic activity helps in predicting drug interactions and optimizing drug therapy for better patient outcomes.

Review Questions

• What does intrinsic activity measure in pharmacology?
• How does intrinsic activity differentiate between full agonists, partial agonists, and antagonists?
• Why is understanding intrinsic activity important in treating conditions like Myasthenia Gravis and Alzheimer’s Disease?

Related terms

Agonist:

A substance that binds to a receptor and activates it to produce a biological response.

Antagonist:

A substance that binds to a receptor but does not activate it, thereby blocking or dampening a biological response.

Efficacy: The ability of a drug to produce the maximum desired effect once bound to its receptor.