opioid

The World Health Organization defines opioids as compounds extracted from the poppy plant together with semisynthetic and synthetic compounds that have similar properties and can interact with opioid receptors in the brain. The class therefore spans three groups with one shared mechanism. Morphine and codeine are taken directly from the plant. Heroin is semisynthetic, made by chemically altering a compound that came from the poppy. Fentanyl, methadone, tramadol and buprenorphine are synthetic, built in a laboratory from scratch.

Opioids relieve pain, and that is what most of them are prescribed for. At higher doses they also slow breathing, which is how an opioid overdose kills. Naloxone is the antidote: given in time it reverses the effects of an opioid overdose, and it has virtually no effect on someone who has not taken opioids. Together with basic life support, timely naloxone can prevent a death.

The distinction between the three groups matters when reading overdose statistics, because national counts are usually broken down by drug class rather than by individual drug. A figure for opioid involved deaths covers all three groups at once, while a figure for synthetic opioids isolates the laboratory made ones, chiefly fentanyl.