Quality statement 6 - Monitoring and management of opioid analgesic adverse effects

If you are prescribed or given an opioid analgesic for acute pain, your clinician should regularly check for harmful effects and adjust your treatment when necessary. Harmful effects from opioid analgesics include nausea, constipation, itchiness, drowsiness and slowed breathing.

Your clinician will monitor adverse effects by regularly checking your breathing, how drowsy you are and how often you are going to the toilet.

Opioid analgesics can sometimes slow down your breathing to dangerously low levels. Becoming very sleepy after having an opioid analgesic can be a sign your breathing is too slow. When you first start an opioid analgesic, starting with a smaller dose will reduce drowsiness, have less effects on your breathing, and be safer for you. If you do become very sleepy after taking your opioid analgesic medicine, do not take any more opioid analgesics unless you are completely awake. Your clinician will monitor your breathing and adjust your treatment if necessary, such as lowering the dose. Talk to your clinician if you have concerns about sleepiness or your breathing.

Your clinician will prescribe laxatives to prevent or treat constipation. If required your clinician will prescribe appropriate treatments for nausea and vomiting, or itchiness.

If opioid analgesics are prescribed, regularly monitor the patient for adverse effects in line with current best practice guidelines. The frequency of patient monitoring will be influenced by the hospital setting, pain severity, age and comorbidities, and the dose and route of administration of the opioid analgesic. Develop appropriate management strategies for the adverse effects, including adjustments to the dose, route of administration, formulation and type of opioid analgesic.

Prescribe appropriate treatments to prevent and manage opioid analgesic–induced adverse effects: laxatives to prevent or treat constipation, and appropriate treatments for nausea and vomiting, and itchiness.

Patient sedation levels should be monitored and the results documented in the monitoring chart in the patient medical record. Excess sedation is a reliable indicator of respiratory depression (OIVI). Patients with excess sedation (such as a score of greater than 1) should be managed by de-escalating the opioid analgesic dose and continued monitoring. Withhold all opioids until the patient is awake. If more analgesia is needed, a smaller dose should be given regardless of pain score. Monitoring sedation should always be paired with appropriate opioid analgesic prescription and dose adjustment. Excess sedation may require escalation of care, according to locally approved protocols. Consider the administration of naloxone to reverse respiratory depression (OIVI), according to a locally approved protocol.

CNS depressants such as benzodiazepines or other sedative hypnotics, barbiturates, and gabapentinoids increase the risk of excess sedation. These medicines should be avoided and patients taking these medicines should be subject to increased monitoring.

Patient cohorts at risk of excess sedation and respiratory depression (OIVI) include people who take opioid analgesics chronically; and patients with sleep-disordered breathing, chronic obstructive pulmonary disease, diabetes, hypertension, hepatic and renal impairment, neurological diseases and obesity. Patients with these comorbidities should be subject to increased monitoring.

Ensure systems and protocols are in place for clinicians to monitor and manage opioid analgesic adverse effects such as nausea, constipation, sedation, and signs of overdose including respiratory depression (OIVI). Ensure monitoring of sedation levels and appropriate action when sedation levels increase. Ensure all clinicians are aware of these systems and protocols.

Ensure protocols are in place to escalate care. Ensure all clinicians are aware of these protocols.

Where electronic healthcare records are in place, consider incorporating PowerPlans, flags and reminders of opioid analgesic adverse effects into the record management system.

Sedation scores

• 0 = awake, alert
• 1 = easy to rouse, remains awake
• 2 = easy to rouse, unable to remain awake
• 3 = difficult to rouse

1. A score of 2 is taken to indicate early respiratory depression (OIVI) and therefore the aim should be to titrate an opioid so that a patient’s sedation score is always less than 2.
2. Note that a sedation score (e.g. ‘sedation score less than 2’) may be specified in the ‘Max dose/24 hrs’ in the PRN section of the national inpatient medication chart to indicate the maximum amount to be administered in 24 hours when prescribing opioids.

Other tools and guidelines

• Faculty of Pain Medicine, Australian & New Zealand College of Anaesthetists. Opioid Dose Equivalence Calculation Table
• South Australian Paediatric Clinical Practice Guidelines. Acute Pain Management and Opioid Safety in Children
• Clinical Excellence Commission NSW. Managing Side Effects of Opioid Medicines in Hospital: Information for patients, families and carers
• Victorian Quality Council, Victorian Department of Human Services. Acute Pain Management Measurement Toolkit,