Methadone

Methadone, sold under the brand names Dolophine and Methadose among others, is a synthetic opioid agonist used for chronic pain and also for opioid use disorder. It is used to treat chronic pain, and it is also used to treat addiction to heroin or other opioids. Prescribed for daily use, the medicine relieves cravings and removes withdrawal symptoms. Withdrawal management using methadone can be accomplished in less than a month, or it may be done gradually over a longer period of time, or simply maintained for the rest of the patient's life. While a single dose has a rapid effect, maximum effect can take up to five days of use. After long-term use, in people with normal liver function, effects last 8 to 36 hours. Methadone is usually taken by mouth and rarely by injection into a muscle or vein.

Methadone
Clinical data
Trade namesDolophine, Methadose, others
AHFS/Drugs.comMonograph
MedlinePlusa682134
License data
Pregnancy
category
  • AU: C
Addiction
liability
High
Routes of
administration
By mouth, intravenous, insufflation, sublingual, rectal
Drug classOpioid
ATC code
Legal status
Legal status
Pharmacokinetic data
Bioavailability15-20% subcutaneous

100% intravenous

41–99% (by mouth)
Protein binding85–90%
MetabolismLiver (CYP3A4, CYP2B6 and CYP2D6-mediated)
Onset of actionRapid
Elimination half-life15 to 55 hours
Duration of actionSingle dose: 4–8 h
Prolonged use:
• Withdrawal prevention: 1–2 days
• Pain relief: 8–12 hours
ExcretionUrine, faeces
Identifiers
  • (RS)-6-(dimethylamino)-4,4-diphenylheptan-3-one
CAS Number
PubChem CID
IUPHAR/BPS
DrugBank
ChemSpider
UNII
KEGG
ChEBI
ChEMBL
CompTox Dashboard (EPA)
ECHA InfoCard100.000.907
Chemical and physical data
FormulaC21H27NO
Molar mass309.453 g·mol−1
3D model (JSmol)
ChiralityRacemic mixture
  • CCC(C(C1=CC=CC=C1)(C2=CC=CC=C2)CC(N(C)C)C)=O
  • 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?)  (verify)

Side effects are similar to those of other opioids. These frequently include dizziness, sleepiness, vomiting, and sweating. Serious risks include opioid abuse and respiratory depression. Abnormal heart rhythms may also occur due to a prolonged QT interval. The number of deaths in the United States involving methadone poisoning declined from 4,418 in 2011 to 3,300 in 2015. Risks are greater with higher doses. Methadone is made by chemical synthesis and acts on opioid receptors.

Methadone was developed in Germany in the late 1930s by Gustav Ehrhart and Max Bockmühl. It was approved for use as an analgesic in the United States in 1947, and has been used in the treatment of addiction since the 1960s. It is on the World Health Organization's List of Essential Medicines.

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