Subcutaneous opioid algorithm

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Please note this guidance is for use in in-patients and is not designed for managing patients with chronic pain

General Management

Only the following opioids may be used : Morphine or Oxycodone.
The following patients may be considered for the opioid algorithm:
Patients with poor intravenous access, no oral route established

CAUTION should be exercised and the opioid dose reduced in the following:
Elderly patients
Patients with renal impairment
also refer to the Acute Pain Renal Guidelines.
Patients with liver impairment - the opioid may precipitate encephalopathy

The following patients are NOT SUITABLE for the Opioid Algorithm:
Patients with poor peripheral circulation (altered drug absorption) i.e.severely hypotensive patient, septic patient.
Patients with oedema or poor skin condition at the injection site.
Patients with head injuries.
Patients whose pain is of a chronic non-malignant nature.

All patients should have patient intravenous access (if at all possible).

Nursing staff must be competent in the use of the opioid algorithm and have in-service training on its use.

All ward areas must have Naloxone (400microgram injection) immediately available.

All opioid analgesia must be prescribed on the patient’s drug Kardex

An anti-emetic should also be prescribed on drug Kardex.

Insertion of subcutaneous cannula

Only use the dedicated cannula for the subcutaneous route for a needle-free administration technique.

Place the cannula in the following areas only:

  • Deltoid area is the area of choice
  • Abdominal area

Explain the procedure to the patient and use Ametop cream if desired. Using a universal clean technique, insert the cannula at a 45 degree angle through the skin. If it is inserted at a shallower angle, the cannula may lie in the dermis layer, causing increased stinging when the opioids are administered.

The dead space of the cannula is 0.2ml.  The first dose of analgesia may have to be increased to allow for this dead space.

Apply a transparent dressing.  This will allow detection of any leakage.  Close the white clamp.  Do not flush the cannula.  Document the time and date on dressing.

Document the date, time and place of cannula in the nursing notes.  The cannula must be replaced every 72 hours unless there are any signs of swelling, inflammation or infection, in which case it should be re-sited earlier.  Document removal of cannula in the nursing notes.

Administration of opioid

Follow the Subcutaneous opioid guidance prior to administering opioid dose

Follow the opioid guidance, ensuring that the controlled drug policies are adhered to.

Draw up the prescribed analgesia using a 2ml syringe and a green needle using a universally clean technique with correct hand hygiene.

Open the white clamp, remove the luer-lock bung and clean the port with 70% isopropyl alcohol swab.

Attach the syringe (do not use a needle) and slowly administer the drug over 40 to 60 seconds.  Do not flush the cannula.

Observation of the patient
  • Blood pressure, pulse, respiratory rate, pain score and sedation score must be recorded on the NEWS chart as follows:

½ hour after each administration of opioid.

The minimum observation there after is 4 hourly, but patient’s condition may require these to be more frequent.

  • If the respiratory rate is less than 7 per minute or sedation score is 3

Administer 10 litres/minute of oxygen via a face mask

Contact the ward doctor and stay with patient.

Administer Naloxone intravenously in 100 microgram increments, every minute, until the respiratory rate is above 10 per minute. Max 400mcg then ask for review.

The patient needs to be observed every 15 minutes for the next hour and hourly after that, to ensure the respiratory depression has not recurred. If it does, a Naloxone infusion may be needed.

Assess for other contributing causes eg hypovolaemia.

Reduce subsequent doses of Opioid by half and also assess if the patient’s pain can be managed with regular paracetamol and NSAID alone, or with weaker opioid.

Inform the Acute Pain Nurse or ITU anaesthetist of this patient and for further advice.

  • Stop the Opioid algorithm when the patient has an established oral route.


Complications - respiratory depression/sedation

NSAIDs and paracetamol help to minimise opioid side-effects by reducing the total dose of opioid required and should be prescribed regularly not PRN.

Moderate respiratory depression (respiratory rate less then 9 breaths per minute AND sedation score of 1 or 2)

  • Ensure a clear airway and administer Oxygen therapy 10 litres/minute via facemask.
  • Monitor respiratory rate, sedation score and oxygen saturation every 15 minutes until respiratory rate is 10 per minute or more.
  • Review the analgesia and consider other causes of respiratory depression.
  • Contact the Acute Pain Team for further advice.

Severe respiratory depression (respiratory rate less then 7 breaths per minute OR sedation score of 3.)


  • Ensure a clear airway and administer Oxygen therapy 10 litres/minute via facemask.
  • Contact the Ward FY1, Surgical Registrar or Nurse Practitioner.
  • Give naloxone 100 micrograms intravenously*. Repeat after 1 minute until there is an adequate response. Give up to a maximum of naloxone 400 micrograms
  • Review analgesia, consider and exclude any other causes of respiratory depression - hypovolaemia, anaphylaxis or cardiac problems.
  • Contact the Acute Pain Nurse or Intensive Care Unit (ITU) Anaesthetist to reassess analgesic requirements and whether a Naloxone infusion is required.

*Prepare naloxone in a 5ml syringe using 3mls of 9% sodium chloride and 400 micrograms (1ml) naloxone to give a solution containing naloxone 100 microgram/ml, checking expiry date of both drug and diluent.

Administer the Naloxone intravenously in 100 microgram (1ml) increments every minute, until the respiratory rate is greater than 10 and the patient’s sedation score is 0 or 1.

Maximum dose of Naloxone should be 400 micrograms. If this dose has not given an adequate response then consider other causes of respiratory depression.

Other complications
  • Nausea and vomiting - give prescribed anti-emetic and refer to Post-operative Nausea and Vomiting (PONV) guideline.
  • Urinary retention - Contact ward doctor or Nurse Practitioner.
  • Hypotension - Unlikely to be caused by Opioids, consider other causes such as bleeding, sepsis, anaphylaxis or myocardial insufficiency.
  • Decreased bowel motility - As bowel motility returns, patients often experience spasmodic “colicky” pain, for which they use Opioids. General support and advice should be given. Please give prescribed laxatives, if required.
  • Mobility - Patients should be encouraged to mobilise, nurses should support as required when mobilising.
Editorial Information

Last reviewed: 30 November 2018

Next review: 30 November 2020

Author(s): Acute Pain Team, Raigmore Hospital

Version: 2

Approved By: TAM Subgroup of ADTC

Reviewer Name(s): Acute Pain Nurse Specialists

Document Id: TAM104