Methadone is a synthetic opioid used medically to manage chronic pain, as an analgesic, and as a maintenance anti-addictive medication for use in patients with opioid dependency. It was developed in Germany in 1937 and introduced into the United States in 1947 by Eli Lilly and Company. Today, 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 The United States. Covidien is the major racemic producer of Methadone, sells bulk Methadone to producers of generic preparations and distributes its own product in the form of tablets, dispersible tablets and oral concentrate under the brand name “Methadose” in the United States.
Methadone is used in the medical field to help with pain and addiction management, Methadone is classified as a Schedule II Drug in The United States and a Class A substance in the United Kingdom. Methadone treatment is illegal in Russia because health officials are not convinced of the medication’s efficacy in treating pain or in opiate replacement therapy.
Methadone is used medically in tablet form or concentrate form as an analgesic, a reliever of chronic pain, and as a maintenance anti-addictive medication in the treatment of opioid dependence. Oral doses of Methadone can stabilize patients by interrupting opioid withdrawal syndrome. 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 their use of these substances altogether.
Methadone linctus, which is about one-third the concentration of the liquid Methadone used for opioid maintenance, is used where available and approved for such use as a cough syrup for violent coughing. Some studies have shown narcotic cough suppressants to be useful against dry, unproductive coughing, but others have shown no benefit.
Additionally, Researchers in Germany have discovered that Methadone has surprising killing power against leukemia cells, including treatment-resistant forms of the cancer. Their laboratory study, published in the August 2008 issue of Cancer Research, a journal of the American Association for Cancer Research, suggests that Methadone shows potential as a new therapy for leukemia, especially in patients whose cancer no longer responds to chemotherapy and radiation.
In Methadone Maintenance Therapy, a form of opiate replacement therapy, Methadone reduces and/or eliminates the use of illicit opiates, the criminality associated with opiate use, and allows patients to improve their health and social productivity. Methadone maintenance indirectly has the potential to reduce the transmission of infectious diseases associated with opiate injection, such as hepatitis and HIV. The principle effects of Methadone maintenance are to relieve narcotic craving, suppress the abstinence syndrome, and block the euphoric effects associated with opiates. Methadone maintenance has been found to be medically safe and non-sedating.
Adverse effects of Methadone include thrombus, hypoventilation, constipation; increased sweating, heat tolerance, chronic fatigue; sleepiness, exhaustion, constricted pupils; nausea, low blood pressure, hallucination; headache, vomiting, cardiac arrhythmia; anorexia, weight gain, gynecomastia; stomach pains, dry mouth, perspiration; flushing, itching, difficulty urinating; swelling of hands, feet, arms and legs; agitation, mood swings, blurred vision; insomnia, impotence, skin rash; seizures and, in some cases, sudden death.
With regards to analgesic properties, drugs similar to Methadone include Morphine, Heroin, Opium and Codeine. A close relative of Methadone is dextropropoxyphene (a Schedule II drug of the United States Controlled Substances Act), first marketed in 1957 under the trade name of Darvon. Oral analgesic potency is one-half to one-third that of Codeine. Other analogues of Methadone that are still in clinical use are dipipanone (Diconal) and dextromoramide (Palfium).
Other drugs that are not structurally related to Methadone but are also used in maintenance treatment include Subutex (buprenorphine) and Suboxone (buprenorphine combined with Naloxone).
As with other opioid medications, tolerance and dependence upon Methadone usually develop with repeated doses. There is some clinical evidence that tolerance to analgesia is less with Methadone compared to other opioids, but this may be due to its activity at the NA receptor. Tolerance to the different physiological effects of Methadone varies; tolerance to both analgesic properties and euphoria develops quickly, whereas tolerance to constipation, sedation, and respiratory depression develops slowly.
The physical withdrawal symptoms from Methadone include hotheadedness, runny nose; yawning, sneezing, nausea; vomiting, diarrhea; sever itching, fever, sweating; chills, tremors, akasthisia; tachycardia, aches and pains of the joints, elevated pain sensitivity; elevated blood pressure and reduced breathing.
The cognitive withdrawal symptoms from Methadone include suicidal tendencies, intense cravings, depression; reduced breathing, spontaneous orgasm, prolonged insomnia; delirium, auditory hallucinations, visual hallucinations; increased olfaction, decreased sex drive, agitation; anxiety, panic, paranoia, and delusions.
Methadone withdrawal symptoms have shown to be up to twice as severe than those of morphine or heroin at equivalent doses and are significantly more prolonged; methadone withdrawal symptoms can last for several weeks or more. Being on a constant dose of say 100 mg. for one year, can take 18 to 24 months for safe detoxification. At high maintenance doses, stopping therapy suddenly can result in withdrawal symptoms described as “the worst withdrawal imaginable,” lasting from weeks to months.
Methadone’s delayed narcotic effect and its lack of a potent high are important contributing factors in Methadone overdose. Symptoms of Methadone overdose may include slow and shallow breathing and weak pulse; sometimes the breathing altogether stops which leads to death, bluish skin, fingernails and lips; spasms of the stomach, intestinal tract, constipation; low blood pressure, pinpoint pupils, drowsiness; disorientation, and coma. For adults who have never taken Methadone before, a single day’s maintenance dose of Methadone between 50-100 mg can prove to be lethal. Children may overdose if they mistake the medication for a drink. A 10 to 20 mg Methadone dose can prove to be fatal to a child.