Related Experiment Video
Updated: Jul 14, 2026

Assessment of Morphine-induced Hyperalgesia and Analgesic Tolerance in Mice Using Thermal and Mechanical Nociceptive Modalities
Published on: July 29, 2014
Using methadone to treat opioid-induced hyperalgesia and refractory pain
David J Axelrod1, Barbara Reville
1Thomas Jefferson University Hospital, Philadelphia, Pennsylvania, USA.
Abstract:
A patient was treated for several years with high doses of opioids for malignant pain. During a recent hospitalization, the patient's pain remained uncontrolled despite escalating doses of various opioids. We suspected that this patient suffered from the clinical phenomenon of opioid-induced hyperalgesia (OIH). The patient was then rotated from her other opioids to methadone, and her pain was adequately controlled within several days. Methadone, because of its NMDA antagonist properties, offers an effective treatment for OIH. The use of methadone for analgesia is complex and should be undertaken only by practitioners who have appropriate experience.
Related Concept Videos
Opioid Analgesics: Synthetic and Semisynthetic Opioids
Analgesia and Pain Management
Opioid Analgesics: Morphine and Other Natural Cogeners
Opioid Receptors: Overview
Phase II Reactions: Methylation Reactions
The mechanism of methylation unfolds in two stages. The first stage sees a methyltransferase enzyme facilitating the transfer of a methyl group from S-adenosylmethionine (SAM) to the substrate, forming S-adenosylhomocysteine (SAH). The second stage involves further metabolism of SAH into homocysteine, which can be recycled...
