Opium

Opium is the dried or coagulated latex obtained from the unripe seed capsule of <em>Papaver somniferum</em>. It is CAS 8008-60-4 — an identifier for the <strong>material</strong>, not a single-molecule formula, because opium is a variable natural mixture rather than one compound. Its principal alkaloids are morphine, codeine, thebaine, noscapine and papaverine.

<strong>Morphine is one constituent of opium, not another name for the whole material</strong>, and heroin is a semi-synthetic derivative made from morphine rather than from opium itself. Legal texts therefore distinguish the plant, raw opium, prepared opium, medicinal opium, the individual alkaloids, and preparations measured by morphine content.

<strong>Raw, prepared and medicinal opium are legal terms, not interchangeable editorial variants.</strong> Raw opium generally describes the plant latex before adaptation for medicinal use; prepared opium commonly means opium processed for smoking; medicinal opium is raw opium processed or standardised for medicinal use under the applicable pharmacopoeial definition. The exact boundary is instrument-specific, and this page preserves each statute's own term. Historical market terms include <em>chandu</em>. Laudanum and paregoric are opium preparations, not synonyms for raw opium.

Opium acts through the opioid alkaloids it contains rather than through any activity of its own. Morphine, the dominant one, is an agonist at the mu-opioid receptor; codeine is a prodrug that must be metabolised to morphine to have appreciable effect.

Mu-opioid agonism in the brainstem produces analgesia and, at higher occupancy, suppresses the drive to breathe. In the gut it slows motility, which is the basis of the constipation that accompanies every opioid and of opium's historical use against dysentery.

The practical consequence of it being a plant preparation is that alkaloid content is not fixed. Two samples of the same weight can differ substantially in morphine content by origin, season and processing, so dose is not reliably inferable from quantity.

Opium's opioid alkaloids can reduce pain and produce sedation and euphoria. They can also cause nausea, constipation, impaired alertness and respiratory depression.

Repeated exposure can produce tolerance, physical dependence and opioid use disorder. Overdose risk rises with dose and is especially high when opioids are combined with alcohol, benzodiazepines or other central nervous system depressants.

<strong>Because illicit opium is a variable mixture, its morphine content and potency cannot be reliably inferred from gross weight alone.</strong> That is a safety point and a legal one: several statutes test gross opium weight, some test morphine content, and some test both.

Respiratory depression is the acute danger and it is dose-dependent, with the ceiling set by the sample's unknown morphine content rather than by its weight. Combining opium with alcohol, benzodiazepines or other sedatives compounds it sharply.

Dependence is expected with sustained use, and withdrawal — while rarely dangerous in a healthy adult — is severe enough to drive relapse on its own. Tolerance falls quickly during any break in use, so the dose that was routine before a period of abstinence, imprisonment or hospital admission is the dose that kills afterwards.

Naloxone reverses opioid overdose, including from opium, and it works on the morphine and codeine in it exactly as it works on any other mu-agonist. It is short-acting relative to a large oral opioid load, so repeat dosing and emergency care are needed after a reversal.