ECHO Hamrahi 6th session 10 May 2022

Methadone in pain management

Factors which make prescribing methadone stressful/difficult:

Unfamiliarity with the drug
Used for unstable patients with poorly controlled pain, in what may already be a stressful situation
Toxicities and interactions
- Many potential drug interactions, which may increase or decrease bioavailability of methadone
Long time to steady state which also varies according to age and hepatic function
Complexities of converting from a different opioid to methadone, with conversion ratios changing as previous MEDD rises

However, developing expertise in prescribing methadone for pain management is important because:

It can be used at a low dose as an adjuvant analgesic with actions beyond opioid receptors
- Therefore has a role in treating neuropathic pain, opioid poorly responsive pain, when opioid tolerance is diagnosed
It is recommended for patients with severe renal impairment such as hepatic metabolism
Once steady state reached, can dose twice a day, so effectively as a long acting opioid which is important when slow release morphine formulations are unavailable or too expensive.
It is affordable
If an institution has RMI, they can order methadone as well as morphine. NB RMI is not specific to any particular opioid. It allows institution to order any opioid.