Methadone 20mg is an opioid analgesic synthesized in 1937 by the Germans Max Bockmühl and Gustav Ehrhart (IG Farben) who were looking for an analgesic that would be easier to use during surgery and thus, Have less potential for addiction. The methadone molecule has a chiral carbon atom – C6 which carries 4 different substituents – it is therefore in the form of two enantiomers:
Which are differentiable by their opposite rotatory power. The form used in therapy is racemic, that is, the 50:50 mixture of the two forms.
Methadone 20mg has been used since 1960 as a substitute for opiates in heroin users under the leadership of Vincent Dole. Its use has been legal in France since 1995. In general, the mixture of the D and L isomers is used, although the activity sought is almost entirely due to the L form. As a narcotic analgesic, methadone is used to Relieve severe pain.
According to the legislation in force in each country, the prescription of methadone may be subject to the laws on the prescription of psychotropic substances.
Methadone 20mg is rapidly absorbed in the gastrointestinal tract and the first analgesic effects appear after 15 to 30 minutes in syrup and 1 to 1h30 in capsule. The duration of action is six to eight hours. On repeated administration, duration of action and half-life (15 to 55 hours) also increase.
The plasma therapeutic level of methadone is approximately 100-400 μg · l-1 (micrograms / liter) and the toxic plasma level is about 1,000 to 2,000 μg · l-1 (micrograms / liter).
Methadone 20mg is mainly metabolized in the liver by mono- and di-N-demethylation and then spontaneously converts to a cyclic structure, on the one hand 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP, Methadone primary metabolite) and 2-ethyl-5-methyl-3,3-diphenylpyrrolidine (EMDP, secondary metabolite) on the other hand. Methadone is also metabolized by hydroxylation to methadol, followed by N-demethylation to normethadol. Methadone, EDDP and EMDP also undergo hydroxylation followed by glucuronidation. The major metabolites of methadone are inactive
In a 2011 survey of 292 clinical experts in Scotland, methadone was ranked 12th for personal injury and 10th for societal harm on 19 current recreational drugs3.
Main article: Opiate substitution treatment.
Introduced into the United States in the 1960s by Dole and Nyswander4, they were first used for serious heroin addicts, such as for soldiers returning from Vietnam.
The aim of the medication is to substitute the consumption of opiates for a euphoric effect (heroin, morphine and certain analgesics) to help the person stabilize his cravings5. Together with medico-social care in the context of a withdrawal cure, methadone treatment aims to stabilize the person’s addiction and harm reduction. The aim of this medicalization is to reduce the risks inherent in drug use: the risks associated with the injection of intravenous substances or nasal administration (including HIV and hepatitis C), risks Overdose or overdose, and risks associated with illegal activities to obtain heroin (deal, prostitution). Moreover, when a person is under methadone treatment, they will experience virtually no euphoria if they consume heroin. This discourages many consumers from relapsing. The introduction of medication can be an integral part of a global process of abstinence.
Methadone 20mg has the advantage of being a long-acting opiate, preventing the sensation of lack and relapse of heroin use. It is taken orally, in one dose per 24h and in some cases two doses per 24h for short “metabolizers”, in the form of bitter and non-injectable solution, capsules or suppositories. In general, the syrup is in the liquid formula of 1% methadone hydrochloride: 1 ml of solute represents 10 mg of methadone hydrochloride.
Medical recommendations indicate a usual maximum daily dose of 60 mg per 24 h6. Studies in Switzerland have shown that some patients require higher doses of 80 mg, 200 mg or 250 mg at the start of treatment 7. The maximum dose prescription may be limited by the laws on the supply of psychotropic substances depending on the country.