A Review of Common Methods to Convert Morphine to Methadone.
A review of common methods to convert morphine to methadone.
J Community Hosp Intern Med Perspect. 2012; 2(4):
Wong E, Walker KA
When dosed appropriately on carefully chosen patients, methadone can be a very safe and effective choice in managing chronic pain. Many authors have discussed important issues surrounding patient selection, drug interactions, screening for QTc prolongation and monitoring. 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. Despite many publications dedicated to addressing this challenging topic, there is no consensus on the most appropriate method for converting an opioid regimen to methadone. Given the lack of concrete guidance, clinicians in a community setting are likely to be faced with an increased challenge if there are no available pain specialists to provide clinical support. Common methods for converting morphine to methadone will be reviewed and two clinical patient scenarios used to illustrate the outcomes of applying the methods.
HubMed – Methadone
Abuse-related effects of µ-opioid analgesics in an assay of intracranial self-stimulation in rats: modulation by chronic morphine exposure.
Behav Pharmacol. 2013 Jul 21;
Altarifi AA, Rice KC, Negus SS
Intracranial self-stimulation (ICSS) is an operant procedure in which responding is maintained by electrical brain stimulation. Stimulation frequency can be varied rapidly to maintain a wide range of baseline response rates, and drugs’ effects can be evaluated simultaneously on both low ICSS rates maintained by low stimulation frequencies and high ICSS rates maintained by high stimulation frequencies. ICSS ‘facilitation’ indicates drug-induced increases in low ICSS rates and is often considered an abuse-related effect, whereas ICSS ‘depression’ indicates decreases in high ICSS rates and may indicate abuse-limiting effects. This study examined the roles of µ-agonist efficacy and of previous µ-agonist exposure as determinants of µ-agonist effects on ICSS in rats with electrodes implanted into the medial forebrain bundle. The high-efficacy, intermediate-efficacy, and low-efficacy µ agonists methadone, fentanyl, and nalbuphine were tested during escalating regimens of morphine exposure (vehicle, 3.2, and 18 mg/kg/day). During vehicle treatment, methadone and fentanyl primarily depressed ICSS, whereas nalbuphine produced weak facilitation that was not dose dependent. Chronic morphine produced tolerance to ICSS depression and increased expression of ICSS facilitation. These results suggest that µ-agonist exposure increases the expression of abuse-related ICSS facilitation by µ agonists with a broad range of efficacies at µ receptors.
HubMed – Methadone
Higher methadone doses are associated with lower mortality in patients of opioid dependence in Taiwan.
J Psychiatr Res. 2013 Jul 20;
Liao DL, Chen PC, Chen CH, Hsieh CJ, Huang YF, Shih WY, Cheng JJ
Optimal methadone dosage and service profile is challenging in treatment of opioid dependence. This study explores the impact of methadone dosage on the mortality of opioid-dependent patients in methadone maintenance therapy by using a large-scale and continual supervised dosing registry information system. Database of nationwide enrolled opioid-dependent patients at methadone clinics in Taiwan during 2006-2008 was assessed. The relative risk of age, sex, marital status, HIV infection and methadone dosage were analyzed by Cox regression analysis. Among all of the 33,549 recruited patients, the crude mortality rate was 134.78/10,000 person-years, and the standardized mortality ratio was 4.68. A dose-response relationship of higher- vs. lower-dosage groups on the risk of mortality risk was observed (adjusted HR = 0.68, P = 0.016). In further sub-grouping analysis, this trend was more significant in HIV positive patients, in subgroup of patients who continuously staying in MMT, and in subgroup of patients who re-enter MMT. This dosage effect is not significantly seen in patients receiving MMT more than 365 days. Further exploration of other treatment-related factors may be important for understanding the long-term treatment outcome of opioid addiction patients.
HubMed – Methadone
Methadone NIMBY Vol I – Residents are being forced to have a clinic placed in their communities without a voice.
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