Pharmacokinetics of Methadone

  title={Pharmacokinetics of Methadone},
  author={Ralph A. Lugo and Kristin Satterfield and Steven Edward Kern},
  journal={Journal of Pain \& Palliative Care Pharmacotherapy},
  pages={13 - 24}
Methadone is a synthetic opioid that is effective for the relief of moderate-to-severe pain and for the treatment of opioid dependence. The pharmacokinetics of methadone differ from those of morphine in that methadone has a higher bioavailability, a much longer half-life, and is hepatically metabolized by cytochrome P450 enzymes. The pharmacokinetics of methadone are variable and an understanding of the factors that impact the onset, magnitude, and duration of analgesia is required to optimize… 
Pharmacokinetics of the injectable formulation of methadone hydrochloride administered orally in horses.
The PK profile of methadone was characterized by high clearance (Cl/F), small volume of distribution (V(d)/F) and short elimination half-life (t(1/2)) and the mean of the estimated t( 1/2) (SD) for each dose was 2.2.
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Methadone: applications in pediatric anesthesiology and critical care medicine
Given its long half-life and high oral bioavailability, methadone has had a primary role in the outpatient treatment of patients with a history of opioid abuse or addiction and makes it a valuable agent in the treatment of both acute and chronic pain of various etiologies.
Commentary Is Levorphanol a Better Option than Methadone ?
  • Medicine
  • 2015
Background. Methadone has been a stalwart pharmacologic option for the management of opioid drug dependence for many years. It substitutes for opioid agonists and possesses certain pharmacokinetic
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    Reactions Weekly
  • 2022
Methadone can be used safely for chronic pain management, but the drug’s long half life necessitates concurrent ordering of a short acting opioid to cover the patient on an as needed basis until the methadone has reached steady state serum levels.
A review of common methods to convert morphine to methadone
  • Eric Wong, K. Walker
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  • 2012
This article will focus on the dosing dilemma that exists after the patient is deemed an appropriate candidate for methadone and a conversion is necessary from another opioid.
The Use of Low-Dose Methadone as Add-On to Ongoing Opioid Treatment in Palliative Cancer Care—An Underrated Treatment?
Continuous administration of opioids, including low-dose methadone, has been proven effective and safe in reducing pain in dying patients without increasing the risk of confusion, regardless of age.
Methadone Pharmacokinetics in Geriatric Critically Ill Patients Following Intramuscular and Intravenous Administration: A Pilot Stud
Based on the results, bioavailability of intramuscular Methadone in geriatric ICU patients was low and less than 40% of the dose was absorbed within first 12 hours.


Stereoselective pharmacokinetics of methadone in chronic pain patients.
The data suggest that both enantiomers of methadone should be measured if correlations between pharmacodynamics and kinetics are made due to the stereoselective differences in half-life, total volume of distribution, and clearance.
Important clinical pharmacologic considerations in the use of methadone in cancer patients.
Methadone is an effective analgesic whose pharmacokinetics must be appreciated in order for it to be used safely and effectively.
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Interindividual Variability of the Clinical Pharmacokinetics of Methadone
Because of the high morbidity and mortality associated with opioid dependence, it is of major importance that methadone is used at an effective dosage in maintenance treatment: at least 60 mg/day, but typically 80–100 mg/ day.
Methadone--metabolism, pharmacokinetics and interactions.
The effects of methadone and its role in fatalities
An overview of the chief effects of methadone on the human body is presented, considering its metabolism, drug interactions and tolerance, and some basic information is provided for those dealing with individuals who have consumed Methadone.
Rectal methadone in cancer patients with pain. A preliminary clinical and pharmacokinetic study.
Rectal methadone can be considered an effective analgesic therapy for patients with cancer pain for whom oral and/or parenteral opioids are not indicated or available.