Naloxone
 Naloxone | |
| 17-Allyl-6-deoxy-7,8-dihydro-14-hydroxy-6-oxo-17-normorphone | |
| Empiric formula | C19H21NO4 |
| Molecular weight | 327.27 |
| Bioavailability | ? |
| Metabolism | Liver |
| Elimination half life | 1-1.5 hours |
| Excretion | Urine |
| ATC code | V03AB15 |
| Pregnancy category | B (USA) B1 (Aus) |
Naloxone is a drug used to counter the effects of overdosing on opiates such as heroin or morphine. It is being offered under the trade names Narcan, Nalone, and Narcanti.
The drug is derived from thebaine and has an extremely high affinity for the opiate receptors on nerve cells in the brain, and blocks those receptors quickly, often throwing addicts into immediate withdrawal symptoms. It acts as a competitive antagonist, being structurally similar to morphine while lacking morphine-like effects.
Naloxone is injected, usually initially intravenously for fastest action. The drug acts after about two minutes, and its effects may last about 45 minutes.
Naloxone has been distributed as part of emergency kits to heroin addicts, which has been shown to reduce death rates.
The drug also blocks the action of pain-lowering endorphins which the body produces naturally. The likely reason for this is that these endorphins operate on the same opiate receptors. In one experiment, women treated with naloxone reported higher pain levels during childbirth than women not so treated; in another experiment, the pain lowering effect of placebos was blocked if the placebos were administered along with naloxone.
While naloxone is still often used in emergency treatments for opiate overdose, its clinical use in the long-term treatment of opiate addicts is being increasingly superseded by naltrexone. Naltrexone is structurally similar but blocks a wider range of opiate receptors, can be administered orally and works for a longer period of time.
The patent for Naloxone has expired and it is manufactured by various companies. The CAS number of naloxone is 465-65-6; the anhydrous hydrochloride salt has CAS 357-08-4 and the hydrochloride salt with 2 molecules of water has CAS 51481-60-8.
External link
- Report on Naloxone and other opiate antidotes (http://www.inchem.org/documents/antidote/antidote/ant01.htm), by the International Programme on Chemical Safety
Categories: Antidotes | Opioid antagonists