Continuous subcutaneous infusion

CSCI stands for Continuous Subcutaneous Infusion and is a common method of administration of medications in palliative medicine, especially for patients near the end of their life. It is typically used in preference to the IV route it is a simpler method of administration and seen as kinder.

Indications

Use when the oral route is unavailable, e.g.

• In patients too drowsy to swallow
• In patients who are vomiting

Comparative dosing

• Dexamethasone: 4mg orally = 4mg SC (use as stat doses)
• Diclofenac: 150mg oral = 75mg SC (use only as CSCI as tissue necrosis has been reported with stat doses)
• Haloperidol: 2mg oral = 1mg SC
• Hydromorphone: 3mg oral = 1mg SC
• Levetiracetam: 250mg oral = 250mg SC (use only as CSCI)
• Levomepromazine: 25mg oral = 12.5mg SC
• Methadone: 10mg oral = 5mg SC (typically used as a stat dose rather than via CSCI)
• Morphine: 30mg oral = 10mg SC (use as stat doses for break-through pain and via CSCI for background pain)
• Ondansetron: 8mg oral = 4mg SC (typically used as a stat dose rather than via CSCI)
• Oxycodone: 10mg oral = 5mg SC (use as stat doses for break-through pain and via CSCI for background pain)
• Ranitidine: 100mg oral = 50mg SC
• Valproate: 200mg oral = 200mg SC (use as CSCI)

Combinations

Mixing mediations in subcutaneous infusions can cause problems if there are drug incompatibilities that cause reactions. Look for crystallization when mixing medications.

Some common compatible combinations are noted below:

• Morphine (or oxycodone) plus
  • Haloperidol
  • Levomepromazine
  • Metoclopramide
  • Haloperidol plus hyoscine butylbromide
  • Haloperidol plus midazolam
  • Haloperidol plus octreotide
  • Haloperidol plus midazolam plus hyoscine butylbromide
  • Haloperidol plus midazolam plus metoclopramide
  • Haloperidol plus midazolam plus hyoscine butylbromide
• Fentanyl plus
  • Haloperidol
  • Hyoscine butylbromide
  • Metoclopramide
  • Haloperidol plus midazolam
  • Haloperidol plus midaozolam plus hyoscine butylbromide
• Opioid-free combinations
  • Haloperidol plus ondansetron
  • Haloperidol plus hyoscine butylbromide plus octreotide plus ranitidine

Clinical example

A patient on 50mg twice daily MR oxycodone and 10mg three times daily of oral metoclopramide for bony pain from metastatic prostate cancer presents to the Emergency Department with vomiting following chemotherapy. His pain has flared up because he is vomiting up his oxycodone. To ensure he continues to receive his pain relief and to ensure he receives anti-emetics, a continuous subcutaneous infusion of analgesia is commenced.

Current outpatient regimen is converted to a subcutaneous regimen

• 50mg of twice daily MR oxycodone = 100 mg of oral oxycodone daily = 50mg of SC oxycodone daily
• 30mg of oral metoclopramide daily = 30mg of SC metoclopramide daily

A slight dose reduction of oxycodone is used as the 2:1 ratio of oral to SC varies from person to person. Thus the pump is started at:

• Oxycodone 40mg via CSCI over 24 hours AND
• Metoclopramide 30mg via CSCI over 24 hours