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Three Part Question

In a [patient with sickle cell disease presenting with a painful crisis] is [subcutaneous morphine more effective than intravenous morphine] at [reducing pain]

Clinical Scenario

A 30 year old male with sickle cell disease presents to the emergency department with pain in the arms and legs for the last few days. The pain was in keeping with her standard painful crisis. As you promptly treat her for the pain you wonder if subcutaneous morphine is a more appropriate way to administer pain relief compared to I.V morphine

Search Strategy

MEDLINE (1966 to present)
EMBASE (1988 to present)
OVID: [sickl$.mp.] AND [exp Anemia/ or anaemia$.mp] OR [exp Anemia, Sickle Cell/ or sickle cell crisis.mp.] AND [painful.mp. and crisis.mp.] AND [exp Injections, Subcutaneous] OR [subcutaneous.mp. or exp Subcutaneous Drug Administration] OR [exp Intravenous Drug Administration/ or intravenous morphine.mp.] AND [exp morphine] Limit to Humans and English language

Search Outcome

This search yielded 228 articles. Bibliographic references found in these articles were also examined to identify related literature. Only original research articles were included. Two articles directly addressed the question. The Cochrane library was also searched but no relevant results were found.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Platt A 2002 USA	Sickle cell disease patients	Review	pain management	Intravenous therapy is the route of choice because of the rapid onset of action, predicable distribution and minimal pain or local tissue damage from the drugs.	No raw data on any trials that may have been carried out
Rees D 2003 UK	Sickle cell disease	Guideline	pain management	Intravenous analgesia is rapid and avoids absorption problems	No raw data on any trial that may have been carried out

Comment(s)

There have been no trials carried out on the comparison between subcutaneous injections and intravenous injections in patients with sickle cell disease. One study done between 1988 and 1990 comparing subcutaneous and intravenous hydromorphone infusions in the management of cancer pain found no significant difference in analgesic efficacy or side effects between the two routes of administration. However they commented on the fact that morphine is ten times less lipid soluble than hydromorphone and that its absorption from subcutaneous administration might be slower, consequently reducing the bioavailability of morphine.[1] Though a study on the comparison done in 1984 does not support this contention.[2]. It seems the advice is that intravenous is the administration of choice due to its rapid onset of action and predicable distribution. However in patients with poor venous access subcutaneous administration would be the administration of choice as it is simple and effective though the unpredictable rate of absorption from the site results in a variable quality of analgesia.

Clinical Bottom Line

Intravenous administration should be the route of choice except in patients with poor venous access.

References

1. Platt, A Treating sickle cell pain: An update from the georgia comprehensive sickle cell centre Journal of emergency nursing 2002;297-303
2. Rees D Guidelines for the management of the acute painful crisis in sickle cell disease Blackwell publishing 2003;744-752