From the Guidelines
Methadone stays in your body for approximately 30 hours due to its long half-life, but its analgesic effect lasts only 6 to 8 hours. This discrepancy is crucial for managing chronic pain in patients, especially those with opioid use disorders 1.
Key Factors Influencing Methadone Duration
- Dosage and frequency of use: These factors significantly affect how long methadone stays in the system, with higher doses potentially leading to longer detection times.
- Metabolism: Individual metabolic rates can vary, influencing how quickly methadone is processed and eliminated from the body.
- Age, weight, liver function, and hydration levels: These factors can also impact the drug's metabolism and excretion.
Detection in Drug Tests
Methadone can be detected in various bodily fluids for different durations:
- Urine tests: 2-7 days after use
- Blood tests: up to 24 hours
- Saliva tests: 1-10 days
- Hair tests: up to 90 days
Clinical Implications
Given methadone's long half-life of 30 hours 1, it is often dosed once daily for opioid use disorders. However, for chronic pain management, this dosing schedule may not provide adequate analgesia throughout the day, necessitating split-dosing strategies in some cases. Methadone clinics can facilitate this by dispensing morning doses and providing take-home bottles for later self-administration, particularly for patients who are fast metabolizers or pregnant 1. The decision to split-dose methadone should be made cautiously, considering the patient's substance use disorder status, adherence to treatment, and the potential for increased opioid tolerance.
From the FDA Drug Label
After multiple dose administration the apparent plasma clearance of methadone ranged between 1. 4 to 126 L/h and the terminal half-life (T1/2) ranged between 7 to 59 hours. The slow release from the liver and other tissues may prolong the duration of methadone action despite low plasma concentrations Methadone can stay in the body for 7 to 59 hours due to its terminal half-life range, and its lipophilic nature allows it to persist in the liver and other tissues, potentially prolonging its action 2.
From the Research
Methadone Duration in the Body
- The duration that methadone stays in the body is not directly addressed in the provided studies 3, 4, 5, 6, 7.
- However, it is known that methadone is a long-acting opioid agonist, which means it can stay in the system for an extended period.
- The studies primarily focus on the comparison of methadone with other medications for opioid use disorder, such as buprenorphine and naltrexone, in terms of efficacy, safety, and outcomes 3, 4, 5, 6.
- One study discusses the management of post-operative pain in a patient with a prior history of opioid use disorder, using a multimodal analgesic plan with buprenorphine 7.
- Another study examines the impact of fentanyl use on the initiation and discontinuation of methadone and buprenorphine/naloxone among people with prescription-type opioid use disorder 5.
- A literature review explores the association between depression and outcomes of methadone and buprenorphine treatment among people with opioid use disorders 6.
- A study compares the risks of cardiac arrhythmias, long QT syndrome, and mortality between patients with opioid use disorders who were prescribed methadone, buprenorphine, or naltrexone 4.