moleculefinder

Methadone

C21H27NO309.4 g/mol Calculated

Also called Adanon, Algovetin, Amidone and Diaminon.

A long-acting opioid used for opioid use disorder and for chronic pain. Its long stay in the body is the point: one dose covers a day.

Sources and notes
  • The introductionfrom sourceMoleculeFinder curated
  • Other namesfrom sourcePubChem / Wikidata
  • Formula and weightcomputedPubChem
  • 2D drawingcomputedPubChem structure, drawn by RDKit
  • 3D modelfrom sourcePubChem 3D conformerLoaded after the page has painted, and on a phone only when you ask for it; the 2D drawing shows until it arrives.

Where you encounter it

Dispensed on prescription, not sold on a shelf.

Sources and notes
  • The line abovefrom sourceMoleculeFinder curatedFrom the group the molecule belongs to.

Explore its structure

Choose a part to light it up.

A C=O with a carbon on each side. Its oxygen accepts hydrogen bonds but has no hydrogen to give, and it resists oxidation better than an aldehyde.

From: standard chemistry.

Sources and notes
  • The drawingcomputedPubChem structure, drawn by RDKitThe page's one shipped drawing, with the chosen part lit in amber under it.
  • The partscomputedFound by ruleEach part is found by a chemical pattern, never picked by hand atom by atom; its words say where they come from.

Properties and sources

Calculated by PubChem

Molecular formula
C21H27NO
Molecular weight
309.4 g/mol
XLogP3octanol/water, log units
3.9
Polar surface areatopological
20.3 Ų
H-bond donors
0
H-bond acceptors
2
Rotatable bonds
7
Complexity
346

Measured LD50, HSDB via PubChem

86 mg/kg pure methadone, rat, oral

An LD50 is an animal study measurement, not a dose for a person.

Reported Hazard label (GHS), ECHA, HSDB via PubChem

Danger Toxic pictogram (GHS06) and Irritant pictogram (GHS07); hazard statements H300, H336, H412

Reported Licence

The US Food and Drug Administration licenses Methadone for human use (NDA 021624, authorized August 13, 1947). Drugs@FDA

Groups it belongs to

Category
Prescription medicine
Family
Opioids
Chemical groups
Aromatics, Ketones
Elements
Nitrogen
Hazard classes
Acutely toxic, Irritant, GHS Danger
SMILESCCC(=O)C(CC(C)N(C)C)(C1=CC=CC=C1)C2=CC=CC=C2

PubChem CID 4095 · Wikidata Q179996 · InChIKey USSIQXCVUWKGNF-UHFFFAOYSA-N · Data refreshed

How MoleculeFinder sources and labels its data

Questions
What is Methadone?
A long-acting opioid used for opioid use disorder and for chronic pain. Its long stay in the body is the point: one dose covers a day.
How toxic is Methadone?
The reported LD50 of Methadone is 86 mg/kg (rat, oral). An LD50 is an animal study measurement, not a dose for a person. Its GHS hazard label carries the signal word Danger and the hazard pictograms Toxic and Irritant. from sourcefrom source
What kind of molecule is Methadone?
Methadone has the formula C21H27NO and a molecular weight of 309.4 g/mol. MoleculeFinder files it under opioids, in the prescription medicine group. from sourcefrom sourcefrom sourcefrom source
Who licenses Methadone as a medicine?
The US Food and Drug Administration licenses Methadone for human use (NDA 021624, authorized August 13, 1947). from source
Sources and notes
  • Calculated valuescomputedPubChemComputed from the structure, so no laboratory conditions apply; complexity is PubChem's own structural score.
  • LD50from sourceHSDB via PubChemOther values the sources report: rat, intravenous, 11 mg/kg; rat, another route, 18 mg/kg; rat, another route, 30 mg/kg. The page shows the one LD50 the site uses everywhere.
  • Hazard labelfrom sourceECHA, HSDB via PubChemThe label combines these classifications.
  • ECHAfrom sourceAttributionSource: European Chemicals Agency, echa.europa.eu.
  • Licencefrom sourceDrugs@FDARead 2026-10-21.
  • Data refreshedfrom sourceMoleculeFinder2026-11-09