Definition of Terms
Opioid analgesia is indicated for the treatment of
moderate to severe pain. An opioid is a medication that relieves pain by
binding to opioid receptors in the central nervous system spinal cord and
peripheral nervous system. This guideline does not cover opioid delivery via
patient controlled analgesia (PCA) delivery.
To provide medical and nursing staff at the Royal Children’s Hospital with a clear outline for assessment and management of a patient receiving opioids as an inpatient, including administration and adverse events associated with administration.
Definition of Terms
- Authorised persons: Nurse or medical staff registered to administer opioids
- CPMS: Children’s Pain Management Service (acute pain)
- Duration of action: Time the drug action lasts at an effective concentration
- Half-life: Time it takes for the medication to reduce by 50% in the plasma level
- IV: Intravenous
- Miosis: Excessive constriction of the pupil of the eye
- Myoclonus: Spasmodic jerky contraction of groups of muscles
- Opioid agonist: A medication with maximal physiological effect at the opioid receptors e.g. morphine
- Opioid antagonist: A medication that occupies the opioid receptors but has no physiological action e.g. naloxone
- SC: Subcutaneous
- Tremor: Involuntary contraction or twitching of one or more body parts
- VPPCP: Victorian Paediatric Palliative Care Program
There are three main types of opioid receptors, these receptors have multiple actions:
Mu (m) receptors are primarily responsible for analgesia and side effects of opioids and are associated with analgesia and side effects (Table 1). Side effects occur regardless of which opioid is used and are generally dose related. Mu receptors subtyped: mu-1 & mu-2.
- mu-1 receptor is primarily responsible for analgesia
- mu-2 receptor is primarily responsible for the opioid side effects
Delta (d) receptors are involved with modulation of mu receptors. Primarily responsible for spinal analgesia
Kappa (k) receptors are associated with miosis, spinal analgesia and sedation
Opioids are metabolised in the liver and excreted via the kidneys. Morphine is
the most commonly used opioid of choice, and has two main metabolites M3G and
M6G. M3G (morphine -3 glucuronide) has no analgesic action, but can cause
neurotoxic effects such as tremor and myoclonus. M6G (morphine – 6 –
glucuronide) is a powerful analgesic.
Table 1: Side effects of opioids
- Respiratory Depression
- Pruritus (itch) *
- Nausea & Vomiting
- Delayed gastric emptying
- Reduced appetite
- Urinary retention
- Muscle rigidity** chest wall (rare) Acute effect of IV fentanyl
*Fentanyl primarily on the face, Morphine generalised
**Acute effect of IV fentanyl
Table 2: List of opioid medications
| Opioid generic name
|| Medication information
- Pure mu opioid agonist
- Varied formulations and release (oral suspension and tablet (IV/ SC)
- Metabolism primarily by the liver and excreted primarily by the kidneys. Metabolites may accumulate in patients receiving infusions or with renal impairment
- Onset of action 20 minutes
- Duration of action 60-90 minutes
- Half-life 2 hours
- Synthetic mu opioid agonist
- Intranasal/transdermal/IV/SC and SL
- Lipophilic drug therefore may result in accumulation
- Metabolised almost exclusively by liver, less than 10% un-metabolised excreted by kidneys
- Onset of action immediate when given IV
- Duration of action 15mins
- Half-life 1.5 hours
- Synthetic mu opioid
- Varied formulations (oral/IV/IM/SC)
- Metabolism almost exclusively by liver
- Excreted by kidneys
- The hydromorphone metabolite H3G may accumulate in patients receiving long-term hydromorphone infusions or patients with renal impairment. H3G can cause CNS disturbances (including confusion, tremor and agitation)
- Onset of action 5min
- Duration of action 20mins
- Half-life 2.5 hours
- Semisynthetic mu opioid agonist
- Oral suspension or tablet /IV/SC
- Oral oxycodone will have faster onset of action than that of oral morphine, better bioavailability and longer duration of action. Also has lower rate of adverse effects and fewer concerns about metabolites than morphine
- Metabolism by liver, excreted by kidneys
- Onset of action 10-15 minutes
- Duration of action 3-6 hours
- Half-life 2-4 hours
- Synthetic serotonin and noradrenaline reuptake inhibitor, atypical centrally acting
- 70% active metabolite M1 30% mu opioid agonist effect
- Oral or IV
- Onset of action 30 minutes
- Duration of action 6 hours
- Half-life 5-7 hours
Regular observations (Table 3) of patients are indicated during the time a patient receives an opioid infusion to monitor the efficacy of pain management.
Pain assessment and measurement as per the clinical
nursing guideline, and to recognise and prevent adverse effects such as
sedation and respiratory depression. More frequent observations should be
undertaken in patients receiving an administration of an opioid bolus
Note that observations for patients on long term opioids
can be altered to reflect their tolerance and need for less interruption. This
decision can be made by the treating team or CPMS and documented for the
Patients receiving opioid infusions in the high risk category (Table 5) are ideally admitted to a room that supports line of sight by nursing staff (e.g. close to the central desk in each pod). Patients in Table 5 require continuous pulse oximetry for the duration of their opioid infusion due to their high risk of an adverse event. Effectiveness of the analgesia and any bolus administration should be recorded in the patient clinical observation and progress notes.
Infants 6 months or less who meet the criteria in Table 6 should be monitored following any surgical procedure for the first 24 hours of opioid therapy in intensive care. These patients are at higher risk due to the combination of opioid administration intraoperatively and post operatively, pain and splinting, fluid overload and risk of hypoventilation in the patient’s EMR progress notes
- Sedation nearly always precedes respiratory depression, therefore this is the most important observation as a clinical indicator
- Any observations that transgresses the yellow zone VICTOR chart criteria should be reported to the treating team and CPMS (observations that transgress red zone MET criteria should constitute a MET call 22 22)
- Pain assessment and score to be documented as per Table 3 and Table 4
Table 3: Observations required for documentation for a patient receiving an opioid infusion
Sedation score, respiratory rate and heart rate:
Pulse oximetry: hourly for duration of opioid infusion
1 hourly until the opioid infusion is ceased and then observations should be performed in conjunction with the
Observation and Continuous Monitoring Guideline
- Pain score:
1 hourly while awake
- Vomiting score:
1 hourly for the first 12hrs, then 4 hourly as indicated
Table 4: Observations required for documentation for a patient following administration of a bolus
- Sedation score and Respiratory rate: every 5 minutes for 15 minutes and then return to routine observations.
- Pulse oximetry: if indicated and for all infants under 6 months of age
- Pain assessment Pain score prior to and following the bolus
Table 5: Patients considered at high risk of an adverse event
- Infants 6 months or less
- Ex-premature infants
- Patients with a history of sleep apnoea or airway obstruction
- Airway surgery e.g. tonsillectomy and/or adenoidectomy
- Pre-existing respiratory co-morbidity e.g. recent RSV infection
- Patients with comorbidities including cerebral palsy, craniofacial disorders, muscular dystrophy or neurological conditions including neurosurgery or traumatic brain injury
- Concurrent use of sedatives or mucopolysaccarides
- Renal impairment
Table 6: Criteria for post-operative monitoring in intensive care
- Significant prematurity e.g. <35 weeks at risk of apnoea
- History of apnoea
- Chronic lung disease
- Significant co-morbidities (e.g. airway abnormalities, cardiac abnormalities,
significant head trauma/neurological disease)
Who are undergoing a surgical procedure and are likely to require an opioid infusion or oral opioid in the post-operative period, are at high risk for apnoea and deterioration on the wards. This can occur because of the combination of anaesthesia, opioid analgesia, pain and diaphragm splinting, fluid overload, and late identification of under-ventilation. These infants should be monitored in PICU for the first 24 hours, then when stable returned to the ward. Monitor these infants with oximetry, respiratory rate monitoring, no oxygen unless hypoxaemia, and monitor analgesia requirements and fluid balance.
Opioid infusion preparation
A continuous opioid infusion can provide continuous analgesia without the peaks and troughs of intermittent bolus only administration
- The opioid infusion must be prepared in accordance with RCH medication management policy and the syringe labelled clearly with a blue intravenous additives label.
- The infusion pump and infusion line should be clearly labelled with the small blue IV opioid infusion labels as an additional safety feature.
- The two authorised persons who make up each opioid syringe must sign and verify the record of infusion
- Preparation and dilution of opioids https://www.rch.org.au/anaes/pain_management/Opioid_Infusion/
- Intravenous preparation of opioids for infusions.
- An infusion pump must be used for all opioid infusions and programmed using the appropriate guardrails profile and medication.
- Bolus doses of opioid infusion (as prescribed on ‘Opioid Infusion ‘) should ONLY be administered using the ‘bolus button’ on the syringe pump, which delivers the bolus in increments of up to 2 mL. If the syringe pump is in the ‘ON’ mode during the bolus, this will add the bolus volume to the total volume infused. The hands free mode is preferable for delivering a bolus.
- Rosella and Butterfly intensive care units have special considerations in regards to preparation and administration.
Opioid infusion administration
- Unless the patient has received a recent dose of opioid, a loading dose should be administered (according to the EPIC prescription) at the commencement of the infusion to ensure therapeutic plasma levels are quickly reached.
- For rapid relief of pain (or anticipated pain), the prescribed bolus dose should be administered.
- The infusion rate may be adjusted by the nurse within the dose range specified, according to the patient’s level of pain.
- It takes approximately four half-lives (~8hrs for morphine/hydromorphone, ~1.5hrs for fentanyl) to reach steady state plasma concentration if given as an infusion, therefore if the rate is to be increased, a bolus should be given as well.
- A multi modal regime should be used to decrease the opioid requirement and therefore improve pain management while decreasing opioid side effects.
Ideally the infusion rate should not be increased unless 3 boluses are required in a 1 hour period.
- The volume infused should be checked every hour and rate verified on the fluid balance flow chart.
Patient receiving an opioid infusion may be at risk of adverse effects including
pruritus, urinary retention, over sedation and respiratory depression. The
treatment of intolerable opioid side effects is the opioid antagonist naloxone.
The half-life of Naloxone is 30-60 minutes, therefore if a patient is given
Naloxone for sedation or respiratory depression they must be monitored for 4
hours. Naloxone is available in the ward impress drug cupboard and on the ward
Table 8: Naloxone doses for side effects
| Naloxone indication
|| Maximum dose per administration
| Opioid induced pruritus and urinary retention
| Excess sedation
- Refer to Figure 1 for steps to follow in the event of respiratory depression or over sedation
- Both M3G and M6G metabolites may accumulate in patients receiving long-term morphine infusions or patients with renal impairment.
- Prolonged fentanyl infusion may result in drug accumulation and potential increase in opioid related side effects.
- Development of opioid tolerance with long-term administration of opioids may require the opioid dose to be increased or an opioid rotation. Careful tapering of doses is important when weaning long-term opioids to avoid opioid withdrawal.
Figure 1: Response to over sedation or respiratory depression events
- Not all patients receiving opioid infusions are under the supervision of CPMS. If the primary treating team wishes the patient to be seen by CPMS, a referral needs to be made by one of the treating team by paging 5773 (24 hours) and completing an electronic inpatient referral. The referrer needs to ensure that the patient's primary consultant has approved CPMS involvement.
- CPMS reviews patients twice daily on week days and once daily on weekends and public holidays.
- If analgesia is inadequate or the patient is experiencing side-effects, CPMS must be called to review the patient.
- CPMS can be contacted at all times on pager 5773 or Spectralink 52702.
Ceasing an opioid infusion
- The decision to cease the opioid infusion should ideally be made in consultation with CPMS.
- Oral opioids may be administered immediately after the opioid infusion is ceased.
- Any remaining opioid infusion must be disposed of according to Drugs, Poisons and Controlled Substances Regulations (2006), Division 7.
- When opioid infusions are used, NO ADDITIONAL ORAL/ INTRAVENOUS opioids or sedative agents should be given without prior consultation with CPMS or an anaesthetist.
- Paracetamol, clonidine, ketamine, local anaesthetics, tramadol and NSAIDs, gabapentin may be prescribed and administered concurrently with opioid infusions. They may help to reduce opioid requirements and associated side effects.
- If the patient is receiving other medication that may cause sedation (e.g. antihistamines, benzodiazepines, baclofen pump or anticonvulsants), the patient may be at increased risk of sedation and respiratory depression.
- Patients who have a Patient Controlled Analgesia (PCA) may be given Control Release oxycodone (Targin) as a background to the PCA
Palliative care goals of care are different and should be discussed with VPPCP
- Pain assessment is performed using the mPAT. The mPAT is a valid, reliable, clinically useful and feasible tool. See:
Neonatal Pain Assessment CPG
- Preparation of opioids is of a different strength as per unit policy, infusions should be changed prior to discharge from Butterfly to RCH inpatient wards
- The half-life of opioid analgesics may be increased and renal drug excretion may be prolonged due to immature renal function.
- Neonates on opioid analgesic medications should have continuous cardiorespiratory monitoring (ECG, RR, Sp02). The only exception for this would be on agreement with neonatal consultant when oral opioids are weaning and have reached minimal dosing.
- Patients receiving IV opioid boluses that are also on continuous cardiorespiratory monitoring in the intensive care environment with 1:1 nursing are not required to document following the bolus. Neonatal Pain Management in the NICU Nursing Guideline.
- Pain assessment is performed using the COMFORT B scale a validated tool for assessment of pain in intubated and sedated children
- Preparation of opioids is of a different strength as per unit policy, infusions should be changed to ward strength prior to discharge from Rosella to RCH inpatient ward
- Intubated and ventilated patients are provided a larger bolus dose of opioid due to their protected airway and supported ventilation
- Nurses caring for patients in Rosella that require opioids should be familiar with the PICU pain and sedation guideline and protocol
- Patients receiving IV opioid boluses that are also on continuous cardiorespiratory monitoring in the intensive care environment with 1:1 nursing are not required to document following the bolus.
- Patients in ED are managed as per this guideline unless their destination is Rosella (PICU) or Butterfly (NICU) in which staff can prepare and manage the patient according to that department’s local guideline.
- Pain assessment and management (basic) page 32 RCH Nursing competency framework, Chapter 2, Generic Competencies
- Pain (Analgesia Infusion) RCH Nursing competency framework, Chapter 3, Cockatoo, Kelpie, Koala, Kookaburra, Possum, Rosella, Sugarglider
Evidence table for the Management of the paediatric patient receiving opioids nursing guideline.
Please remember to
read the disclaimer.
The development of this nursing guideline was coordinated by Sueann Penrose, CNC, Children's Pain Management Service, approved by the Nursing Clinical Effectiveness Committee. Published October 2022.