Subcutaneous Morphine Administration in Palliative Care

Recommended Administration Protocol

The British Medical Journal recommends that subcutaneous morphine may be given either as bolus injections every four hours or by continuous infusion for palliative care patients 1, 2
The rescue dose for breakthrough pain should be the same as the regular four-hourly dose and may be given as often as required (e.g., every hour) 3, 4
The total daily dose of morphine should be adjusted daily according to how many rescue doses have been needed in the previous 24 hours 3, 5
If pain returns consistently before the next regular dose is due, the regular dose should be increased 6, 2

The relative potency ratio of oral morphine to subcutaneous morphine is approximately 1:2, meaning subcutaneous doses should be half the oral dose 2
For patients receiving regular subcutaneous morphine every four hours, a double dose at bedtime is recommended to avoid being woken by pain 2
Subcutaneous morphine is preferred over intramuscular administration for chronic cancer pain as it is simpler and less painful 6

Subcutaneous administration of morphine may not be practical in patients with generalized edema, soreness, or sterile abscesses, erythema at injection sites, coagulation disorders, or very poor peripheral circulation [2, @16@]

For patients unable to take oral medications, subcutaneous administration is one of the preferred alternative routes 2, 7
Expert guidelines indicate that this approach produces effective control of chronic cancer pain in approximately 80% of patients [2, @18@]