What it means
A substance that binds to a receptor and makes it act, copying the body's own messengers. Morphine is an opioid agonist; albuterol is a beta-2 agonist. The opposite is an antagonist, which blocks the receptor, such as naloxone for opioids. A partial agonist turns the receptor on only part of the way. In anatomy, an agonist is the muscle that does a movement.
At a glance
| Spanish | agonista |
|---|---|
| Also written | agonists |
Related terms
opioid analgesic
A strong drug that relieves moderate to severe pain by acting on the brain and spinal cord.
beta blocker
A drug that blocks the effects of adrenaline on beta receptors, slowing the heart rate and lowering blood pressure.
bronchodilator
A drug that relaxes the muscles around the airways so they open wider.