Methadone

Methadone is a strong, lab-made opioid prescribed for chronic pain and opioid addiction. Sold under names like Dolophine and Methadose, it is taken daily to ease cravings and withdrawal. Withdrawal management can be completed in under a month, stretched out over a longer period, or continued as lifelong maintenance. A single dose works quickly, but full effects may take up to five days. After long-term use in people with healthy livers, effects last between 8 and 36 hours. It is usually swallowed, and rarely injected into muscle or vein.

Side effects are typical of opioids, including dizziness, sleepiness, nausea, vomiting, and sweating. Serious risks include abuse and slowed breathing. Abnormal heart rhythms can occur due to a prolonged QT interval. In the United States, deaths from methadone poisoning fell from 4,418 in 2011 to 3,300 in 2015. Higher doses carry greater risk. Methadone is made synthetically and works on opioid receptors.

Developed in Germany in the late 1930s by Gustav Ehrhart and Max Bockmühl, it was approved as a painkiller in the U.S. in 1947 and has been used for addiction treatment since the 1960s. It is on the World Health Organization's List of Essential Medicines.

For opioid addiction, methadone can be used as maintenance therapy or short-term withdrawal management. In the U.S., outpatient programs must be certified by SAMHSA and registered with the DEA. A 2009 Cochrane review found methadone effective at keeping people in treatment and reducing heroin use, based on self-reports and urine/hair tests, but it did not affect criminal activity or death risk. Treatment follows either maintenance or withdrawal management. Maintenance therapy is usually outpatient, with a single daily dose to help people avoid illicit opioids. Patients are often observed for 15–20 minutes after dosing to prevent diversion. Treatment lasts from months to years, and may be lifelong since addiction is often a chronic relapsing condition. Starting doses are low (usually no more than 40 mg daily) and increased gradually. Doses of 40 mg per day control withdrawal but not cravings; 80 to 100 mg per day are more successful at reducing heroin use, though higher doses increase overdose risk compared to lower ones (e.g., 20 mg/day). Methadone maintenance reduces transmission of bloodborne viruses like hepatitis B, C, and HIV. Its main goals are to relieve cravings, suppress withdrawal, and block opioid euphoria. Long-term use leads to tolerance and dependence, but when used correctly, maintenance is medically safe, non-sedating, and supports slow recovery. It is widely used for pregnant women addicted to opioids.

For pain, methadone is used in chronic cases, often rotated with other opioids. Because it acts on NMDA receptors, it may work better for nerve pain and may cause less tolerance than other opioids.

Adverse effects include sedation, constipation, flushing, sweating, heat intolerance, dizziness or fainting, weakness, fatigue, drowsiness, constricted pupils, dry mouth, nausea, vomiting, low blood pressure, headache, chest pain or fast heartbeat, abnormal heart rhythms, trouble breathing or slow breathing, lightheadedness, weight gain, memory loss, itching, difficulty urinating, swelling in hands, arms, feet, and legs, mood changes (euphoria, disorientation), blurred vision, decreased libido, difficulty reaching orgasm, impotence, missed periods, skin rash, and central sleep apnea. When used for maintenance, it is usually given as an oral liquid. Methadone has been linked to significant tooth decay, partly due to dry mouth that reduces saliva’s protective role. Other factors include cravings for carbohydrates, poor dental care, and reduced personal hygiene, along with sedation, leading to extensive dental damage.

Withdrawal from methadone is reported as being much longer and more drawn out than withdrawal from opioids with shorter half-lives.