What is Methadose?

Methadone (also known as Symoron, Dolophine, Amidone, Methadose, Physeptone, Heptadon and many other names) is a synthetic opioid. It is used medically as an analgesic and a maintenance anti-addictive and reductive preparation for use by patients with opioid dependence. It was developed in Germany in 1937, mainly because Germany required a reliable internal source of opioids. It is an acyclic analog of morphine and heroin. Methadone acts on the same opioid receptors as these drugs, and has many of the same effects. Methadone is also used in managing severe chronic pain, owing to its long duration of action, strong analgesic effect, and very low cost. Methadone was introduced into the United States in 1947 by Eli Lilly and Company. The number of drug-poisoning deaths involving methadone increased from 784 deaths in 1999 to 5,518 deaths in 2007; then it declined to 4,418 deaths in 2011.

Methadone is listed under Schedule II of the Single Convention On Narcotic Drugs 1961 and is regulated similarly to morphine in most countries. In the United States, it is a Schedule II Narcotic controlled substance with an ACSCN of 9250 and a 2013 annual aggregate manufacturing quota of 25 metric tons, down from just under 30 in 2012. One intermediate in the manufacturing process, 4-cyano-2-dimethylamino-4,4-diphenyl butane, is also listed as a Schedule II Narcotic Intermediate controlled substance with ACSCN 9254 and a quota of 32.5 metric tons. Levomethadone is presumably under Schedule II as an isomer of methadone. The salts of methadone in common medical use are the hydrochloride (free base conversion ratio 0.89) and hydrobromide (0.79); the tartrate was used in the past.

Methadone is mainly used in the treatment of opioid dependence. It has cross-tolerance (tolerance to similar drugs) with other opioids including heroin and morphine, and offers very similar effects but a longer duration of effect. Oral doses of methadone can stabilise patients by mitigating opioid withdrawal syndrome or making it more tolerable. Higher doses of methadone can block the euphoric effects of heroin, morphine, and similar drugs. As a result, properly dosed methadone patients can reduce or stop altogether their use of these substances.

Methadone is approved for different indications in different countries. Common is approval as an analgesic and approval for the treatment of opioid dependence. It is not intended to reduce the use of non-opioid drugs such as methamphetamine or ethanol (alcohol).

A number of pharmaceutical companies produce and distribute methadone. The racemic hydrochloride is the only form available in most countries, such as the Netherlands, Belgium, France and in the United States, as of March 2008. The dextrorotary enantiomer of methadone, dextromethadone, is an NMDA antagonist rather than an opiate agonist. It is on the World Health Organization's List of Essential Medicines, a list of the most important medication needed in a basic health system.

There is now an asymmetric synthesis available to prepare both levomethadone [R-(-)-methadone] and dextromethadone [S-(+)-methadone].