Word parts
What it means
A drug that fits a receptor without switching it on, and so stops other substances from working at that site. Naloxone is an opioid antagonist that reverses opioids; beta blockers block beta receptors. The opposite is an agonist, a drug that switches a receptor on. In anatomy, an antagonist is also a muscle that works against another, such as the triceps against the biceps.
At a glance
| Spanish | antagonista |
|---|---|
| Also written | antagonists, antagonism |
Related terms
opioid analgesic
A strong drug that relieves moderate to severe pain by acting on the brain and spinal cord.
neurotransmitter
A chemical that a nerve cell releases to pass a signal to another nerve, muscle or gland cell.
adrenergic
Relating to nerves and receptors that respond to epinephrine and norepinephrine, or a drug that acts like them.