Drug

PO equianalgesic dose

To convert to OME, multiply by:

To convert from OME, multiply by:

To convert from PO to SC or IVa,b (same drug) multiply by:

Morphine

5 mg

−

−

0.5

Codeine

50 mg

0.1

10

0.5 (SC only; IV not available in Canada)

Oxycodone

2.5-3 mg

1.5-2

0.75-0.5

Not available in Canada

Hydromorphone

1 mg

5

0.2

0.5

Methadone

Methadone is 4-10 times more potent than morphine (see text) and is available in Canada in oral form only.

Conversions between methadone and morphine should be carried out by practitioners experienced in using both medications.

Tramadol

Tramadol is ~8-10 times less potent than morphine.

Buprenorphine

5 microg/h patch = 30 mg OME (total daily morphine dose)

10 microg/h patch = 30-80 mg OME (total daily morphine dose)

Higher doses (35, 52.5, 70 microg/h) available in some countries

Fentanyl

Transdermal fentanyl (patches) is a controlled-release formulation that should be used only in those already on an opioid and at a dose equivalent to ≥60 mg/d OME (24 h). Conversion of morphine to fentanyl: Table 1.24-2

Parenteral formulations available for SC or IV administration

a SC dosing is limited to ≤2 mL per injection site. If concentration of the drug does not allow for this, >1 injection site or conversion to IV dose is required.

b In Canada, the SC route is generally considered equianalgesic to the IV route (the equianalgesic dose ratio of PO to SC and IV is 2:1 for both morphine and hydromorphone). In Europe, the IV route is considered somewhat more potent than the SC route (the PO to SC equianalgesic dose ratio is 2:1 and the PO to IV ratio is considered 3:1).