Methadone is a substance that is a synthetic opioid that exerts a pronounced analgesic effect. It is distinguished in its chemical structure from morphine, but, nevertheless, it has a similar effect. In the postwar period, Soviet scientists, after studying the effect of the drug (it belongs to the group of narcotic analgesics), began to use it instead of morphine. Methadone is also much more effective for oral administration than morphine. Since the mid 60-ies of the XX century, the drug was used to treat “opiate” drug addicts. To reduce the effects of physical dependence on Methadone, the dosage is selected in such a way that it continuously decreases, but without the accompanying deterioration of the patient’s well-being. This treatment is accompanied by the conduct of psychotherapeutic sessions and the parallel assignment of maintenance drugs. As the drug although is used for the treatment of addiction, but in itself is a drug, its use causes many controversies among drug doctors both in the medical plan and in the organizational one – the distribution and control of the drug intake must be done very carefully, otherwise Methadone will get be in the hands of drug addicts and will be used uncontrollably.
The drug is an opioid agonist. Agonists are substances that, in response to receptors, cause a reaction in response. Antagonists are substances that, on the contrary, reduce or block the receptors’ response to natural body signals. A morphine antagonist, for example, is naloxone. Morphine activates the receptors and its molecules join the opioid receptors. And naloxone competitively replaces the receptor, leaving no possibility for the molecules of morphine to join the receptor. The effect of the drug is long, unlike many drugs – up to 36 hours, with a pronounced euphoric reaction, he does not. Due to this, abstinence syndrome after the end of the drug can be minimized. Anesthetic effect of the drug appears in half an hour – an hour after taking and lasts about 5 hours. The drug is rapidly absorbed from the digestive tract when ingested, its bioavailability is 80 – 95%. The drug has a sufficiently long half-life (more than 24 hours), so when taking methadone substitution therapy, you can take the drug once a day, rather than more often. Biotransformation of the drug occurs in the liver, and excretion is performed with feces and urine.
Form of release
The drug is available as a solution for injection and in the form of tablets. Indications. The drug is used as an anesthetic. The drug is used for substitution maintenance therapy in persons with opioid dependence.
For opioid addicts (as a rule, they use heroin) the drug is prescribed orally. To reduce the intensity of manifestation of the withdrawal syndrome, a daily dose of 15 to 40 mg is prescribed. With maintenance replacement therapy, 20 to 120 mg are prescribed. Subsequently, the dosage is smoothly and slowly reduced, and ideally, the dosage reaches zero values and is canceled. As an anesthetic for a severe pain syndrome, the drug is administered as an intramuscular or subcutaneous injection. Injections are done several times a day. The maximum total daily dosage is 120 mg.
Most often there are such undesirable effects as constipation, excessive sweating, insomnia, impaired concentration, sexual weakness. It is not excluded also the appearance of nausea, drowsiness, euphoria, narrowing of the pupils. Interaction. The level of substance in the blood is affected by the use of antiretroviral drugs, some antibiotics, anti-tuberculosis drugs, antiepileptic drugs.
Effects on the body
Therapeutic doses of the drug have a sedative and analgesic effect. The drug affects the nervous and cardiovascular system, and smooth muscle. Overdose causes suppression of blood circulation, respiratory depression, failure of renal function, pulmonary edema. With chronic use – high blood pressure, frequent palpitations, spasms of bile ducts, relaxation and lethargy, hyperglycemia (increased blood glucose level).
The minimum dose of the drug, leading to the death of an accidental user, is 50 mg. For addicts who have already developed tolerance, this dose reaches 200 mg. At casual consumers at concentration of Methadone 1 mkg / ml in plasma, the toxic damage of a liver comes. Concentration of more than 2 mg / ml can lead to death.