Methadone

Description

Methadone is the mainstay of drug treatment in the UK. Extensive international clinical research over several decades supports methadone, and it is undeniably effective for a large number of people who are able to stabilise and rebuild their lives through long-term maintenance prescribing.

It can also be used as a short-term, community-based reducing detox therapy (though long-term maintenance demonstrates substantially higher rates of stability and retention). Methadone is less sedating than street heroin and offers less of a ‘high’. It has a very long elimination half-life (usually over 24 hours), allowing for once-daily dosing (although some patients split their daily dose).

Heroin users seeking a stronger euphoric effect on top of methadone sometimes turn to ‘potentiators’ (other substances that increase sedation, such as alcohol, gabapentinoids, or benzodiazepines). Combining these substances significantly elevates overdose risk.

Key health considerations associated with methadone include dental hygiene (sugar-free liquid formulations are available), reduced libido (common to all long-term opioid use), and anecdotal reports of bone or joint ache, often related to sub-therapeutic dosing.

Pharmacology

Methadone is a synthetic, long-acting full agonist at the µ-opioid receptor (MOR) in the central nervous system. Because of its high oral bioavailability and slow hepatic metabolism, methadone has an elimination half-life ranging between 15 and 60 hours (averaging 24–36 hours).

At stable daily doses, methadone produces steady-state plasma concentrations without the sharp peaks and troughs seen with short-acting opioids like heroin or morphine. This prevents both acute withdrawal symptoms and excessive sedation.

At therapeutic doses (typically 60–120mg daily), methadone occupies opioid receptors sufficiently to produce a ‘blockade’ effect: if a person uses illicit heroin or morphine on top of their methadone, the supplementary opioid produces little to no additional euphoric effect, helping to disrupt the cycle of compulsive illicit use.

Harm Reduction

Methadone in Clinical Treatment:

Methadone is one of the most thoroughly researched medicines in clinical practice, and when prescribed and managed correctly, has an excellent safety profile. Evidence consistently demonstrates that daily maintenance doses between 60mg and 120mg are the most effective at reducing illicit heroin use, preventing overdose, and improving physical, psychological, and social functioning.

Getting the Dose Right:

Induction begins with a cautious starting dose (usually 20–30mg) that is gradually titrated upwards until withdrawal symptoms and cravings are completely controlled. Treatment ‘failures’ are often due to sub-therapeutic dosing or overly restrictive pharmacy collection regimes rather than the medication itself.

• Safe storage — keep away from children: Methadone oral syrup is visually attractive to children and ingestion of even a small fraction of an adult dose can be fatal. Always store methadone in a secure, locked container out of sight and reach of children.
• Never inject oral methadone: Oral syrup is heavily laden with sugars, flavourings, and thickeners; injecting it causes severe venous thrombosis, gangrene, and amputations.
• Beware of drug interactions & mixing: Mixing methadone with alcohol, benzodiazepines, pregabalin, or other sedatives is one of the leading causes of fatal overdose. Avoid mixing, or inform your prescriber.
• Carry naloxone: Naloxone successfully reverses methadone overdoses, although because methadone has a long half-life, repeated doses of naloxone and extended emergency medical observation (calling 999) are essential. Visit our Naloxone page.
• Do not stop abruptly: Discontinuing methadone ‘cold turkey’ causes prolonged and intense withdrawal. Any reduction should be planned slowly in consultation with your clinical key worker.
• Dental care: If taking sugar-containing oral solution, rinse your mouth with water after swallowing and maintain regular dental appointments.

History

Methadone was first synthesised in Germany in 1937 by scientists Max Bockmühl and Gustav Ehrhart at I.G. Farbenindustrie as part of a search for synthetic analgesic alternatives that would not require imported opium.

After the Second World War, German patents and research records were requisitioned by the Allies. The drug was introduced into clinical medicine in the United States and the UK under trade names such as Dolophine and Physeptone.

In the mid-1960s, pioneering research in New York City by Dr Vincent Dole and Dr Marie Nyswander established methadone maintenance treatment (MMT). Their clinical trials demonstrated that high, stable daily doses eliminated illicit heroin cravings and withdrawal without impairing cognitive function, establishing modern Opioid Substitution Therapy worldwide.

Law

Class A under the Misuse of Drugs Act 1971.
Schedule 2 under the Misuse of Drugs Regulations 2001 (can be possessed legally with a valid medical prescription).

Possible offences

• Possession: Maximum sentence of up to 7 years imprisonment, an unlimited fine, or both (without a valid prescription).
• Possession With Intent To Supply (PWITS): (including giving or selling your prescription to someone else) Maximum sentence of up to life imprisonment, an unlimited fine, or both.
• Supply: Maximum sentence of up to life imprisonment, an unlimited fine, or both.
• Production: Maximum sentence of up to life imprisonment, an unlimited fine, or both.

For more detailed information on sentencing and rights, visit our Drugs Law section.