What is the Difference Between Agonist and Antagonist Drugs?

🆚 Go to Comparative Table 🆚

The main difference between agonist and antagonist drugs lies in their interaction with receptors and their ability to produce a response.

Agonist drugs:

  • Bind to the target receptor and produce a similar response to the intended chemical and receptor.
  • Mimic the actions of a neurotransmitter or hormone to produce a response.
  • Examples include opioid drugs like heroin and methadone, which produce responses such as 'liking', analgesia, and respiratory depression.

Antagonist drugs:

  • Bind to the target receptor but do not produce a response.
  • Stop or slow the responses of the receptor.
  • An example is naltrexone, which binds to a specific receptor in the brain but does not activate it. Instead, it prevents the activation of the receptor by other agonists, resulting in withdrawal.

In summary, agonist drugs simulate the intended reaction by binding to receptors and producing a response, while antagonist drugs bind to receptors but do not produce a response, effectively blocking the receptor from being activated by other substances.

Comparative Table: Agonist vs Antagonist Drugs

Here is a table highlighting the differences between agonist and antagonist drugs:

Agonist Antagonist
Act like neurotransmitters, binding to receptors and producing a specific response. Bind to receptors but do not activate them, effectively blocking the action that would normally occur.
Mimic or enhance the effects of a neurotransmitter or hormone. Often used to inhibit the effects of harmful drugs, such as cocaine and heroin.
Activate receptors in the body, producing a biological response. Examples include naltrexone and naloxone.
Examples of agonist drugs: methadone. Examples of antagonist drugs: naloxone.