Relationship between Serum Methadone Concentration and Cold Pressor Pain Sensitivity in Patients Undergoing Methadone Maintenance Therapy

AuthorZalina Zaharien
AuthorChee Siong Leeen
AuthorMuslih Abdulkarim Ibrahimen
AuthorNurfadhlina Musaen
AuthorMohd Azhar Mohd Yasinen
AuthorYeong Yeh Leeen
AuthorSoo Choon Tanen
AuthorNasir Mohamaden
AuthorRusli Ismailen
Issued Date2018-03-31en
AbstractHyperalgesia is a common clinical phenomenon among opioid dependent patients on methadone maintenance therapy (MMT) and it may be associated with undertreated pain and/or therapeutic failure. This study aimed to investigate association between serum methadone concentration (SMC) and cold pressor pain responses. Cold pressor pain responses in 147 opioid dependent patients on MMT were assessed using cold pressor test (CPT) at 0 h and at 2, 4, 8, 12, and 24 h after the dose intake. Blood samples were collected at 24 h after the dose. Serum methadone concentrations were measured using the Methadone ELISA kit and classified into two categories: < 400 ng/mL and ≥ 400 ng/mL. Eighty-eight patients (59.9%) had trough concentrations of < 400 ng/mL and 40.1% had trough concentrations of ≥ 400 ng/mL. There were significant effects of SMC on the cold pressor pain threshold (p = 0.019). Patients with concentrations < 400 ng/mL had significantly higher (almost 60% higher) cold pressor pain threshold (adjusted mean (95% CI) = 30.15 (24.29, 36.01) s) compared to those with concentrations of ≥ 400 ng/mL (18.93 (11.77, 26.08) seconds). There was also a 20% difference in pain tolerance, and 6% difference in cold pressor pain intensity score, neither of which were significant statistically (p > 0.05). Our results suggest an association of trough methadone concentration with the cold pressor pain threshold among opioid dependent patients on MMT. It would be useful to study the mechanisms underlying this association to help managing pain in such a population.en
DOIhttps://doi.org/10.22037/ijpr.2018.2209en
KeywordCold pressor painen
KeywordPain thresholden
KeywordPain toleranceen
KeywordPain intensityen
KeywordMethadoneen
KeywordMethadone maintenance therapy (MMT)en
PublisherBrieflandsen
TitleRelationship between Serum Methadone Concentration and Cold Pressor Pain Sensitivity in Patients Undergoing Methadone Maintenance Therapyen
TypeOriginal Articleen

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