General aspects of subcutaneous drug administration in palliative care
Subcutaneous drug administration is useful when patients:
- have unmanaged symptoms requiring rapid dose adjustment
- are vomiting
- have impaired gastrointestinal absorption of oral drugs
- are unable to swallow
- are in the last days of life (see Care in the last days of life).
The subcutaneous route is preferred to other parenteral routes (eg intravenous, intramuscular) for patients with palliative care needs because it:
- is less invasive than other parenteral routes
- has a lower risk of infection than the intravenous route
- is less painful than the intramuscular route
- is easier to manage in the home setting than other parenteral routes
- usually results in high drug bioavailability and rapid onset of action.
Many parenteral formulations are not registered for subcutaneous use despite evidence and clinical experience to support their efficacy. See Off-label use of medications for more information about administering drugs by routes that are not specified in their approved indications.
Subcutaneously administered drugs may be given as intermittent doses, or most commonly, as an infusion. Avoid frequent subcutaneous injections; if multiple intermittent doses are anticipated, start a continuous subcutaneous infusion (CSCI).
The site selected for injection or cannula placement should have sufficient subcutaneous fat, good lymphatic drainage and intact skin. The abdomen and chest are preferred sites although the arm and thigh may be used. Avoid skin that is infected, bruised or irradiated. It is best to avoid oedematous tissue and skin near joints. Rotate the cannula site to reduce local reactions, which can arise from the cannula or from the drug(s).