Methadone

Methadone
Clinical data


Trade names	Dolophine, Methadose, others
AHFS/Drugs.com	Monograph
MedlinePlus	a682134
Pregnancy category	AU: C US: C (Risk not ruled out)
Routes of administration	Oral, intravenous, insufflation, sublingual, rectal
ATC code	N02AC52 (WHO) N07BC02 (WHO) QN02AC90 (WHO)
Legal status
Legal status	AU: S8 (Controlled) CA: Schedule I DE: Anlage III (Prescription only) UK: Class A US: Schedule II
Pharmacokinetic data
Bioavailability	41–99% (oral)
Protein binding	85–90%
Metabolism	Liver (CYP3A4, CYP2B6 and CYP2D6-mediated)
Onset of action	rapid
Biological half-life	7–65 hours
Duration of action	4–8 h (one dose), 1–2 days (prolonged use)
Excretion	Urine, faeces
Identifiers
IUPAC name (RS)-6-(dimethylamino)-4,4-diphenylheptan-3-one
CAS Number	76-99-3^Y
PubChem (CID)	4095
IUPHAR/BPS	5458
DrugBank	DB00333^Y
ChemSpider	3953^Y
UNII	UC6VBE7V1Z^Y
KEGG	D08195^Y
ChEBI	CHEBI:6807^N
ChEMBL	CHEMBL651^Y
ECHA InfoCard	100.000.907
Chemical and physical data
Formula	C₂₁H₂₇NO
Molar mass	309.445 g/mol
3D model (Jmol)	Interactive image
Chirality	Racemic mixture
SMILES CCC(C(C1=CC=CC=C1)(C2=CC=CC=C2)CC(N(C)C)C)=O
InChI InChI=1S/C21H27NO/c1-5-20(23)21(16-17(2)22(3)4,18-12-8-6-9-13-18)19-14-10-7-11-15-19/h6-15,17H,5,16H2,1-4H3^Y Key:USSIQXCVUWKGNF-UHFFFAOYSA-N^Y
^NY (what is this?)

Methadone, sold under the brand names Dolophine among others, is an opioid used to treat pain and as maintenance therapy or to help with detoxification in people with opioid dependence. Detoxification using methadone can either be done relatively rapidly in less than a month or gradually over as long as six months. While a single dose has a rapid effect, maximum effect can take five days of use. The effects last about six hours after a single dose and a day and a half after long-term use in people with normal liver function. Methadone is usually taken by mouth and rarely by injection into a muscle or vein.

Side effects are similar to those of other opioids. Commonly these include dizziness, sleepiness, vomiting, and sweating. Serious risks include opioid abuse or a decreased effort to breathe. Abnormal heart rhythms may also occur including prolonged QT. The number of deaths in the United States involving methadone poisoning was 4,418 in 2011, which was 26% of total deaths from opioid poisoning. Risks are greater with higher doses. Methadone is made by chemical synthesis and acts on opioid receptors.

Methadone was developed in Germany around 1937 to 1939 by Gustav Ehrhart and Max Bockmühl. It was approved for use in the United States in 1947. Methadone is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. Globally in 2013, about 41,400 kilograms were manufactured. It is regulated similarly to other narcotic drugs. In the United States it is not very expensive.

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