[10] Withdrawal management using methadone can be accomplished in less than a month,[11] or it may be done gradually over a longer period of time, or simply maintained for the rest of the patient's life.

A 2009 Cochrane review found methadone was effective in retaining people in treatment and the reduction or cessation of heroin use as measured by self-report and urine/hair analysis and did not affect criminal activity or risk of death.

It is not uncommon for treatment recipients to be administered methadone in a specialized clinic, where they are observed for around 15–20 minutes post-dosing, to reduce the risk of diversion of medication.

[10][25] It has been found that doses of 40 mg per day were sufficient to help control the withdrawal symptoms but not enough to curb the cravings for the drug.

Other putative mechanisms of methadone-related tooth decay include craving for carbohydrates related to opioids, poor dental care, and a general decrease in personal hygiene.

Despite methadone's much longer duration of action compared to heroin and other shorter-acting agonists and the need for repeat doses of the antagonist naloxone, it is still used for overdose therapy.

[51] In the UK, persons who are prescribed oral methadone can continue to drive after they have satisfactorily completed an independent medical examination which will include a urine screen for drugs.

[52] Individuals who are prescribed methadone for either IV or IM administration cannot drive in the UK, mainly due to the increased sedation effects that this route of use can cause.

According to the U.S. National Center for Health Statistics,[53] as well as a 2006 series in the Charleston Gazette (West Virginia),[54] medical examiners listed methadone as contributing to 3,849 deaths in 2004.

The consensus report concludes that "although the data remains incomplete, National Assessment meeting participants concurred that methadone tablets or Diskets distributed through channels other than opioid treatment programs most likely are the central factors in methadone-associated mortality.

This QTc prolongation tends to increase the risk of torsades de pointes (TdP), a heart rhythm disturbance that can lead to syncope or sudden death.

People who metabolize methadone rapidly, on the other hand, may require twice daily dosing to obtain sufficient symptom alleviation while avoiding excessive peaks and troughs in their blood concentrations and associated effects.

The most common route of administration at a methadone clinic is in a racemic oral solution, though in Germany, only the R enantiomer (the L optical isomer) has traditionally been used, as it is responsible for most of the desired opioid effects.

Drinkable forms include ready-to-dispense liquid (sold in the United States as Methadose), and Diskets (known on the street as "wafers" or "biscuits") tablets which are dispersible in water for oral administration, used similarly to Alka-Seltzer.

Oral medication is usually preferable because it offers safety, and simplicity and represents a step away from injection-based drug abuse in those recovering from addiction.

[70][71] These particles cannot be filtered out before injection, and will accumulate in the body over time, especially in the lungs and eyes, producing various complications such as pulmonary hypertension, an irreversible and progressive disease.

[72][73][74] The formulation sold under the brand name Methadose (flavored liquid suspension for oral dosing, commonly used for maintenance purposes) should not be injected either.

This practice is much less common nowadays [78] Methadone and its major metabolite, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP), are often measured in urine as part of a drug abuse testing program, in plasma or serum to confirm a diagnosis of poisoning in hospitalized victims, or in whole blood to assist in a forensic investigation of a traffic or other criminal violation or a case of sudden death.

Methadone usage history is considered in interpreting the results as a chronic user can develop tolerance to doses that would incapacitate an opioid-naïve individual.

In particular, it was found that there is an interaction between the tertiary amine and the carbonyl carbon of the ketone function (R3N ••• >C=O) that limits the molecule's conformation freedom, though the distance (291 pm by X-ray) is far too long to represent a true chemical bond.

Farbenindustrie AG at the Farbwerke Hoechst who were looking for a synthetic opioid that could be created with readily available precursors, to solve Germany's opium and morphine shortage problem.

[81][82] On 11 September 1941 Bockmühl and Ehrhart filed an application for a patent for a synthetic substance they called Hoechst 10820 or Polamidon (a name still in regular use in Germany)[83] and whose structure had little relation to morphine or other "true opiates" such as diamorphine (Heroin), desomorphine (Permonid), nicomorphine (Vilan), codeine, dihydrocodeine, oxymorphone (Opana), hydromorphone (Dilaudid), oxycodone (OxyContin), hydrocodone (Dicodid), and other closely related opium alkaloid derivatives and analogues.

[81] The report published by the committee noted that while methadone itself was potentially addictive, it produced "considerably" less euphoria, sedation, and respiratory depression than morphine at equianalgesic doses and was thus interesting as a commercial drug.

[48][81] Morphine produced higher rates of self-administration and reinforcing behaviour in both human and animal subjects when compared to both methadone and pethidine.

In comparison to equianalgesic doses of pethidine (Demerol), methadone was shown to produce less euphoria, but higher rates of constipation, and roughly equal levels of respiratory depression and sedation.

Farbenkonzern and Farbwerke Hoechst were no longer protected, each pharmaceutical company interested in the formula could buy the rights for the commercial production of methadone for just one dollar (MOLL 1990).

[91][92] Brand names include Dolophine, Symoron, Amidone, Methadose, Physeptone, Metadon, Metadol, Metadol-D, Heptanon and Heptadon among others.

People on methadone maintenance in the US either have to pay cash or if covered by insurance must complete a pre-determined number of hours per month in therapeutic groups or counseling.

In 2008, the Chief Sanitary Inspector of Russia Gennadiy Onishchenko, claimed that Russian health officials were not convinced of methadone's efficacy in treating heroin and/or opioid addiction.

[107] Brazilian footballer assistant Robson Oliveira was arrested in 2019 upon arriving in Russia with methadone tablets sold legally in other countries for what was considered drug trafficking under Russian law.