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Management of Subcutaneous Infusions in Palliative Care

Section 4: Drugs and Diluents

Learning Objectives
Drug administration via a subcutaneous infusion device
Commonly used medications for symptom relief
Medications linked to abscess formation
Diluents
Quiz
Answers To All Quiz Questions
References

Learning Objectives

On completion of this section, you should be able to:

  • describe the most commonly used drugs in subcutaneous infusions, and their indications for use;
  • explain which drugs are contraindicated in subcutaneous infusions;
  • state the most commonly used diluent in subcutaneous infusions.

Drug administration via a subcutaneous infusion device

  • a prescription from a medical officer or appropriately credentialled nurse practitioner is required before administering any medication;
  • subcutaneous infusion devices can be used to deliver drugs to treat a variety of symptoms, particularly when other drug routes are no longer available, or are unacceptable to the patient; common symptoms include pain, nausea, vomiting, breathlessness, agitation, delirium and “noisy breathing”1;
  • a wide variety of drugs can be used together in different combinations with no clinical evidence of loss of efficacy2;
  • the more drugs that are mixed together, the greater the risk of precipitation and reduced efficacy3;
  • 2–3 drugs may be mixed in a subcutaneous infusion (occasionally up to 4 drugs4,5);
  • if compatibility is an issue, the use of two subcutaneous infusion devices3 or regular or prn subcutaneous injections should be considered;
  • before mixing any drugs together in a subcutaneous infusion, check stability and compatibility  information3,4,6-8 e.g. with hospital pharmacists; other sources include The Syringe Driver1 and PalliativeDrugs.com12;
  • use of the boost facility, where available, is not advocated; a boost dose rarely provides sufficient analgesia to relieve uncontrolled pain, and may lead to overdosing of other drugs being infused4;
  • it is better to use breakthrough medication to treat uncontrolled symptoms than the boost facility9;
  • normal saline is the most commonly used diluent in Australia10;
  • the use of water for injection has been linked to pain due to its hypotonicity, although normal saline may be more likely to cause precipitation11;
  • 5% dextrose is used only occasionally as a diluent4, and is not commonly used in Australia.12

In the Australian context, symptoms that are encountered at end of life are generally well controlled by use of nine commonly used medications.13

These include:

  • morphine sulphate/tartrate (an opioid);
  • hydromorphone (Dilaudid, an opioid);
  • haloperidol (Serenace, an antipsychotic/antiemetic);
  • midazolam (Hypnovel, a short acting benzodiazepine);
  • metoclopramide (Maxolon, an antiemetic);
  • hyoscine hydrobromide (hyoscine, an antimuscarinic/antiemetic);
  • clonazepam (Rivotril, a benzodiazepine);
  • hyoscine butylbromide (Buscopan, an antimuscarinic); and
  • fentanyl (an opioid).

Temperature may affect drug stability. This can be overcome by ensuring the infusion device is placed on top of bed clothes and outside clothing, rather than beneath them4. Medications contraindicated for use via subcutaneous infusion due to severe localised reactions3,11:

  • prochlorperazine (Stemetil, an antiemetic);
  • diazepam (Valium, an anxiolytic); and
  • chlorpromazine (Largactil, an antipsychotic)

Medications linked to abscess formation when used in subcutaneous infusions:

  • pethidine hydrochloride (pethidine, an analgesic);
  • prochlorperazine (Stemetil, an antiemetic); and
  • chlorpromazine (Largactil, an antipsychotic).1

Diluents

The choice between water for injection and 0.9% (normal) saline as a diluent is a matter of debate. The literature is divided. Some recommend water for injection as the diluent3,4,10,12, while recent literature recommends normal saline.1 Normal saline can be used for most drugs, the main exception being cyclizine.4

Normal saline is most commonly used within Australia for two reasons1:

  • first, the majority of drugs can be diluted with normal saline with only two exceptions: cyclizine and diamorphine (neither of which are commonly used in Australia);
  • second, normal saline is isotonic, as are most injectable formulations. By diluting with normal saline, the tonicity of the solution is unaltered. Water for injection is hypotonic; using it as a diluent will potentially produce a hypotonic solution, which the literature suggests can contribute to the development of site reactions1. For example, use of water for injection has been linked to pain due to its hypotonicity, although normal saline is more likely to cause precipitation.11

Quiz

References

  1. Dickman A, Schneider J, Varga J. The syringe driver: continuous subcutaneous infusions in palliative care. 2nd ed. Oxford: Oxford University Press;2005.
  2. Lichter I, Hunt E. Drug combinations in syringe drivers. The New Zealand Medical Journal 1995;108(1001):224-226.
  3. Mitten T. Subcutaneous drug infusions: a review of problems and solutions. International Journal of Palliative Nursing 2001;7(2):75-85.
  4. Dickman A, Schneider J. The syringe driver: continuous subcutaneous infusions in palliative care. 4th Edition. Oxford: Oxford University Press;2016.
  5. McNeilly P, Price J, McCloskey S. The use of syringe drivers: a paediatric perspective. International Journal of Palliative Nursing 2004;10(8):399-404.
  6. Coleridge-Smith E. The use of syringe drivers and Hickman lines in the community. British Journal of Community Nursing 1997;2(6):292,294,296.
  7. Negro S, Salama A, Sanchez Y, Azuarat M, Barcia E. Compatibility and stability of tramadol and dexamethasone in solution and its use in terminally ill patients. Journal of Clinical Pharmacy and Therapeutics 2007;32:441-444.
  8. Peterson G, Miller K, Galloway J, Dunne P. Compatibility and stability of fentanyl admixtures in polypropylene syringes. Journal of Clinical Pharmacy and Therapeutics 1998;23:67-72.
  9. Lloyd-Williams M, Rashid A. An analysis of calls to an out-of-hours palliative care advice line. Public Health 2003;117(2):125.
  10. Flowers C, McLeod F. Diluent choice for subcutaneous infusion: a survey of the literature and Australian practice. International Journal of Palliative Nursing 2005;11(2):54-60.
  11. British National Formulary. Syringe drivers. <www.bnf.org>. Accessed 26 January 2005.
  12. PalliativeDrugs.com. ‘Document Library: Syringe drivers.’ <www.palliativedrugs.com>. Accessed 25 September 2013.
  13. Joint Therapeutics Commission. A survey of doctors on their preferred medications for various symptoms in palliative care. Brisbane: Unpublished data;2005.

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Last updated: 2 January 2020