Opioid antagonist
Opioid antagonists are receptor antagonists of the opioid receptors .
After administration, opioid antagonists displace the opioid or the opiate ( heroin , codeine, etc.) with the result that the patient often wakes up suddenly and immediately experiences strong withdrawal symptoms . Since the half-life of heroin, for example, is significantly longer than that of naloxone, there is a risk that the patient will fall back into a twilight state after a short time ( rebound effect ). If, after administration of an opioid antagonist, the patient tries to reduce the withdrawal symptoms by taking opiates again, an overdose with possibly fatal consequences is likely. Therefore, patients must be monitored after administration of opioid or opiate antagonists.
Naloxone and naltrexone are competitive antagonists . Buprenorphine is a partial agonist at the µ-opioid receptor. A new substance that cannot cross the blood-brain barrier is methylnaltrexone .
In emergency medicine, the antidote naloxone is usually administered intravenously in the case of life-threatening opiate intoxication .
Individual evidence
- ↑ Abba Kastin: Handbook of Biologically Active Peptides. Academic Press, 2011, ISBN 978-0-080-46379-7 , p. 1369.