Continuous subcutaneous infusions (syringe drivers)

BNF Prescribing in Palliative Care

Portable continuous infusion devices, such as syringe drivers, provide good control of symptoms.
Indications for the parenteral route are:

  1. The patient is unable to take medicines by mouth owing to nausea and vomiting, dysphagia, severe weakness, or coma

  2. There is malignant bowel obstruction and surgery is inappropriate

  3. When the patient does not wish to take regular medication by mouth.

Aligning contents of syringe driver to end-of-life symptoms

  1. Pain control
    Diamorphine hydrochloride is the preferred opioid since its high solubility permits a large dose to be given in a small volume

    Syringe SC diamorphine dose over 24hr is one-third the total oral morphine dose over 24hr
    Syringe SC morphine dose over 24hr is half the total oral morphine dose over 24hr
    Syringe SC oxycodone dose over 24hr is half the total oral oxycodone dose over 24hr
    So, 60mg oral morphine/24hr equates to 30mg SC morphine/24hr equates to 20mg SC diamorphine/24hr

    If breakthrough pain occurs give SC/IM dose that is 1/10 to 1/6 of the total 24-hour SC infusion dose

  2. Nausea and vomiting
    Haloperidol (2.5-10mg/24hr)
    Levomepromazine (5–25 mg/24 hours)
    Cyclizine is particularly likely to precipitate if mixed with diamorphine or other drugs
    Octreotide reduces intestinal secretions and vomiting arising from bowel obstruction.

  3. Agitation, confusion and restlessness
    Haloperidol (5–15 mg/24 hours)
    Levomepromazine (12.5–50 mg/24 hours)
    Midazolam (Initially 10–20 mg/24 hours, adjusted according to response; usual dose 20–60 mg/24 hours)

  4. Excessive respiratory secretions
    Hyoscine butylbromide (20–120 mg/24 hours)
    Glycopyrronium bromide (0.6-1.2mg/24hr)

  5. Bowel colic
    Hyoscine butylbromide (60–300 mg/24 hours)
    Glycopyrronium bromide (0.6-1.2mg/24hr)

  6. Convulsions
    Midazolam (Initially 20–40 mg/24 hours)

Compatibility with diamorphine

Diamorphine can be given by subcutaneous infusion in a strength of up to 250 mg/ml
<40 mg/mL diamorphine use either water for injections or physiological saline (sodium chloride 0.9%) as diluent
>40 mg/mL diamorphine use only water for injections as diluent (to avoid precipitation)

The following can be mixed with diamorphine:

  • Cyclizine may precipitate with diamorphine or sodium chloride diluent 0.9%
    Cyclizine should be mixed with water for injection to reduce the chance of precipitation.

  • Metoclopramide can cause skin reactions, can cause discolouration of infusion

  • Dexamethasone may precipitate

  • Haloperidol may precipitate if haloperidol concentration is above 2 mg/mL

  • Hyoscine butylbromide

  • Levomepromazine

  • Metoclopramide

  • Midazolam

Dr Rajesh VarmaContinuous subcutaneous infusions, syringe drivers