How methadone works
Methadone is used as a painkiller and to treat heroin addiction. As a man-made opioid, it mediates its pain-relieving, withdrawal-inhibiting, cough-irritation-dampening, and sedative effects through so-called opiate receptors.
Methadone as a heroin substitute
In this case, the person’s thoughts only revolve around obtaining the drug, and trembling, sweating and nausea occur. To stop this craving, the synthetic opioid methadone is used as part of substitution therapy.
It binds to the same docking sites (receptors) as heroin, but blocks them for a longer period of time and floods on more slowly, which means that the typical euphoria as with the use of the drug does not occur. The physical craving is satisfied at that moment.
Methadone as a painkiller
In addition to addiction treatment, “levo-methadone” (certain form of methadone) is also used in pain therapy due to its strong analgesic effect.
Uptake, degradation and excretion
In substitution therapy, methadone is swallowed in the form of a syrup or tablets. The active substance is practically completely absorbed in the intestine (approximately 80 percent), and reaches the central nervous system slowly and continuously.
When treating pain, the active ingredient levomethadone can also be injected directly into the bloodstream. The effect then occurs more quickly. Excretion then also takes place via the kidneys.
When is methadone used?
In addition, the analgesic effect of levomethadone is used for very severe pain, for example in the treatment of cancer.
How methadone is used
In substitution therapy, methadone is taken once a day. Initially, it is necessary to swallow the drug daily under the supervision of a doctor or pharmacist.
Under certain conditions, after some time in therapy, patients can take home their weekly supply of methadone with reservations.
What are the side effects of methadone?
Common side effects of methadone are:
- Development of addiction
- Constipation
- Sedation
- Difficulty breathing
- Low blood pressure
- Development of tolerance
- Sweating
- Reduction of the pupils
- Itching
- problems with urination
A rare side effect is prolongation of the so-called QT time (a section in the ECG), whereby cardiac arrhythmias may occur. This side effect is more pronounced with methadone than with levomethadone.
What should be considered when taking methadone?
Methadone should not be taken by:
- concomitant use of monoamine oxidase (MAO) inhibitors
- patients with respiratory depression
- during an acute asthma attack
- Congenital or acquired long-QT syndrome (abnormality in the electrical conduction of the heart)
Drug interactions
Other medications that also affect the central nervous system (brain and spinal cord) may increase the effects and side effects of methadone. These include sedatives, sleeping pills, anti-depression medications, and antipsychotics. This is especially true in combination with alcohol.
Methadone and many other active substances are eliminated from the body via the same degradation pathway. When used at the same time, there may therefore be a mutual influence on the effect and side effects.
This applies, for example, to itraconazole (for fungal infections), ritonavir (for HIV), verapamil (for cardiac arrhythmias), carbamazepine (for seizure disorders), rifampicin (for bacterial diseases) and St. John’s wort extract (for depressive moods).
Trafficability and operation of machines
Methadone impairs the ability to react. During treatment with the active substance, active participation in road traffic and the operation of heavy machinery should therefore be avoided. This applies in particular in combination with alcohol.
Age restriction
Pregnancy and lactation
Methadone has been used for decades in substitution therapy for pregnant women. Accordingly, there is a great deal of experience with the active substance. Opioid-dependent pregnant women receive close interdisciplinary care.
Methadone does not have a teratogenic effect, but withdrawal symptoms are possible in the infant after birth. Delivery is therefore preferably in a clinic with neonatology.
Under certain conditions, mothers undergoing methadone therapy may breastfeed their children. In this situation, too, mother and child are ideally closely monitored by a doctor.
This is how you receive medication with methadone
Since when is methadone known?
Methadone was first synthesized in Germany in 1939 by Max Bockmühl and Gustav Ehrhart. Shortly thereafter, it was approved as a painkiller. It was not until much later that its use as a “substitute” for heroin addiction was added.
Other interesting facts about methadone
Methadone in cancer therapy
So far, only results from cancer cells in laboratory tests and a few animal experiments are available. At the moment, initial studies with human subjects are underway.
Experts advise against routinely prescribing it to cancer patients until further notice – especially because methadone can have dangerous side effects in some cases.
Methadone – problems with use
Recent findings have shown that methadone withdrawal is quite difficult. This is compounded by the frequent misuse of the substance. The substance is stretched with syrup during substitution to increase viscosity and make intravenous use more difficult.
Nevertheless, methadone is traded on the black market and injected by many addicts. Possible consequences are inflammations at the injection site, which can lead to amputation of the arm.
