Methadone Dose Selection for Treatment of Pain Compared with Consensus Recommendations.

BACKGROUND: Many factors make methadone an appealing option for treatment of pain in patients seen by palliative care; however, complex drug-related properties and variable patient response complicate appropriate conversion ratios from other opioids to methadone. Currently, there is no consensus regarding one accepted conversion method.

OBJECTIVE: Current patterns of prescribing for clinicians at a three-hospital academic health system on initial rotation to methadone for the management of pain were compared with a series of consensus recommendations for methadone dose calculation.

DESIGN: Retrospective chart review of 98 hospital patients. Settings/Participants: Adult subjects hospitalized in an academic medical center between January 1, 2013, and January 1, 2015, who were initiated on oral methadone for pain during the same admission.

MEASUREMENTS: Final target daily dose of methadone was calculated using End of Life/Palliative Education Resource Center (EPERC) and Friedman conversion methods based on opioids provided in the prior 24 hours. This was then compared with actual dosing as ordered by clinicians and received by the patient.

RESULTS: Average range of final daily methadone dose for new starts was 18.1 ± 16.7 mg. Final methadone dose as received by two-thirds of patients was below the dosing target calculated by EPERC and Friedman guidelines by an average of 35 mg. In addition, more than 80% of patients' final methadone doses fell below the range recommended by these two methods. No patients received opioid reversal agents during their index hospitalization.

CONCLUSIONS: These findings may question the best approach to clinical application of EPERC and Friedman methods and call for more research to determine the safest, lowest, and most effective methadone target dosing selection. Final methadone dosing as received by patients compared favorably with a conservative methadone dosing method that recommends starting doses no higher than 30-40 mg per day.