Considerations with opioid use in liver impairment
All opioids are metabolised by the liver.
In patients with palliative care needs who have liver impairment:
- Adjust opioid doses cautiously and closely monitor for adverse effects; opioids can precipitate or worsen hepatic encephalopathy by causing constipation and sedation.
- Avoid oral naloxone-containing preparations (eg oxycodone+naloxone); the bioavailability of naloxone is increased (more than 100‑fold in moderate to severe liver impairment), which reduces opioid efficacy.
Patients with severe liver impairment (eg as measured by the Child–Pugh score1 or the Model for End-stage Liver Disease [MELD] score2 have decreased liver function, which can affect the bioavailability, biotransformation, half-life and protein binding of opioids. Choosing the optimal opioid and dosage in these patients can be complex—seek expert advice if necessary. See also Principles of analgesic use in patients with cirrhosis in the Pain and Analgesia guidelines. When starting an opioid in a patient with severe liver impairment:
- use a low dose and consider increasing the dosing interval
- avoid long-acting formulations or drugs—opioid half-lives are prolonged in patients with severe impairment and use of long-acting drugs or formulations increases the risk of drug accumulation.
If a patient develops liver impairment while on opioid therapy, consider seeking expert advice.
For information on palliative care for patients with chronic liver disease, see Principles of palliative care for patients with chronic liver disease.