The opioid conversions provided are based on best available guidelines and product literature.
The equi-analgesic dose of a given opioid can vary considerably between individual patients.
At higher opioid doses, a 25-50% dose reduction of the converted dose should be considered and is provided as an option in the calculation above.
Conversion factors used in this calculator are listed in the table below.
Drug
Route
Conversion factor to oral morphine
Equi-analgesic dose to 100mg oral morphine
Morphine
Oral
1
100mg
Morphine
SC
2
50mg
Morphine
IV
3
33.3mg
Diamorphine
SC
3
33.3mg
Oxycodone
Oral
2
50mg
Oxycodone
SC
3
33.3mg
Codeine
Oral
0.0833
1200mg
Dihydrocodeine
Oral
0.104
960mg
Tramadol
Oral
0.1
1000mg
Fentanyl
Patch
125
33mcg/hr over 24 hours
Buprenorphine
Patch
107
39mcg/hr over 24 hours
Alfentanil
SC
30
3.33mg
Fentanyl
SC
150
667mcg
Fentanyl
IV
300
333mcg
Hydromorphone
Oral
7.5
13mg
Hydromorphone
SC
15
7mg
References:
Mercadante S, Caraceni A. Conversion ratios for opioid switching in the treatment of cancer pain: a systematic review. Palliat Med. 2011;25(5):504-515. doi:10.1177/0269216311406577
