heroin

Heroin, or diacetylmorphine, is a semi-synthetic opioid derived from morphine. It is produced by acetylating morphine and is highly lipophilic, allowing rapid passage across the blood-brain barrier. Heroin is a controlled substance in most countries. Common routes of administration include injection, smoking, and snorting.

In the brain, heroin is rapidly metabolized to morphine and binds to mu-opioid receptors, producing analgesia, euphoria, and sedation. The onset and intensity of effects depend on the route of administration, with injections producing the fastest onset. Common effects include warmth, drowsiness, respiratory depression, pinpoint pupils, nausea, and constipation. Repeated use leads to tolerance and physical dependence; withdrawal can be uncomfortable and prolonged.

Health risks associated with heroin use include the possibility of overdose, which can cause slowed or halted breathing, loss of consciousness, and death. Additional dangers arise from infectious diseases and other complications tied to injection, such as abscesses or blood-borne infections. The risk increases with high-purity heroin or when mixed with other substances. Naloxone can be used to reverse an opioid overdose, but emergency medical care is essential.

Legal status and treatment vary by country. In many places, heroin is illegal to manufacture, possess, or distribute. Some jurisdictions offer heroin-assisted treatment or opioid substitution therapy as part of harm-reduction and addiction services. Treatment options for heroin dependence typically include methadone or buprenorphine maintenance, psychosocial support, and harm-reduction strategies.

History notes: heroin was first synthesized in 1874 and marketed by Bayer in 1898 as a cough suppressant and a non-addictive morphine substitute, but it was later found to be highly addictive and subject to regulation.