Convert methadone to fentanyl patch

John Smith, a terminally ill lung cancer patient has pain that is well controlled on Morphine Sustained Action, 90mg every 12 hours. Smith is now unable to swallow and so the Morphine needs to be converted into a transdermal fentanyl patch. Calculate the hourly dose of the fentanyl patch. See: Facts about the Fentanyl Transdermal Patch. So by applying the patch with the last dose of the oral morphine the chances of increasing pain during the drug transition can be avoided.

Apply 75 microgram fentanyl patch concurrently with the last dose of long acting oral morphine 90mg. The correlation between previous fentanyl dose and the final methadone dose or the fentanyl:methadone dose ratio was assessed by means of Pearson and Spearman correlation coefficients r , respectively.

A Friedman test was used to compare pain intensity before and after the switch and the use of daily rescue doses. Neuropathic pain was not affected by opioid switching.

A positive linear correlation was obtained between the fentanyl and methadone doses Pearson r, 0. Incomplete cross-tolerance can occur due to variability in opioid binding. There is no evidence-based recommendation for an appropriate reduction.

In patients receiving long-acting opioid formulations SR , transdermal , a "rescue" dose for breakthrough pain is recommended. In an inpatient setting, rescue doses can be provided IV every minutes. Oral rescue doses can be offered as needed over the normal dosing interval of the drug typically every 4 hours. As stated above, because equianalgesic tables are inherently inaccurate, the availability of breakthrough doses is paramount.

Because equianalgesic tables are inherently inaccurate, dose titration to optimal effect is essential. Because transdermal fentanyl has a delayed onset and onset of peak activity, consider titrating every 3 days. Show AMA citation. Press 'Calculate' to view calculation results. Load an Example. Duragesic [package insert].

Practice guidelines for transdermal opioids in malignant pain. PMID An alternative algorithm for dosing transdermal fentanyl for cancer-related pain. Oncology Williston Park. American Pain Society.