Naloxone

The drug 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.

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 heroine 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.

The patent for the drug has expired and naloxone is manufactured by various companies.

still missing: chemical formula, image of structure, who discovered it and when