A Case of Opioid Toxicity on Conversion From Extended-Release Oxycodone and Naloxone to Extended-Release Oxycodone in a Patient With Liver Dysfunction

Opioid toxicity after oxycodone/naloxone to oxycodone conversion: case series

Combination preparations of oxycodone/naloxone are marketed to aid in the management of opioid induced bowel dysfunction, with caution advised in prescribing in cases of liver dysfunction.This case series demonstrates four cases of patients with normal liver function tests who developed significant opioid toxicity on conversion from combination oxycodone/naloxone to oxycodone at equivalent doses, necessitating significant dose reduction.In each case, a cause for intra-hepatic shunting such as cirrhosis, porto-systemic collaterals or thrombosis were identified, highlighting these as cautionary features when prescribing combination preparations of oxycodone/naloxone and the possible need for dose reduction if converting to oxycodone.

Oxycodone/naloxone prolonged-release tablets in patients with moderate-to-severe, chronic cancer pain: Challenges in the context of hepatic impairment

Opioids such as oxycodone are recommended in the management of moderate-to-severe, chronic cancer pain. All opioids can potentially cause constipation, which may be a significant barrier to their use. Multiple randomised clinical trials have shown that the use of naloxone as a peripherally acting mu-opioid receptor antagonist, in combination with oxycodone can prevent or reduce opioid-induced constipation while having equivalent analgesic efficacy to oxycodone alone. However, clinical experience has shown that unexpected events may occur in some patients when unrecognized liver impairment is present. We describe the underlying biological reasons and propose simple, but effective steps to avoid this unusual but potentially serious occurrence. In healthy individuals, naloxone undergoes extensive hepatic first pass metabolism resulting in low systemic bioavailability. However, in patients with hepatic impairment, porto-systemic shunting can increase systemic bioavailability of naloxone, potentially compromising the analgesic efficacy of oral naloxone-oxycodone combinations. This reduced first pass effect can occur in a range of settings that may not always be apparent to the treating clinician, including silent cirrhosis, non-cirrhotic portal hypertension and disruption of liver internal vasculature by metastases. Hepatic function test results correlate poorly with presence and extent of liver disease, and are not indicative of porto-systemic shunting. Presence of hepatic impairment should thus be considered when medication-related outcomes with oxycodone-naloxone combination are not as expected, even if liver function test results are normal.

Pharmacovigilance in Hospice/Palliative Care: De-Prescribing Combination Controlled Release Oxycodone-Naloxone

Background: Pharmacovigilance studies in hospice/palliative care provide extra information to improve medication safety. Combination controlled release oxycodone-naloxone offers an alternative opioid with less risk of opioid-induced constipation. Objective: To examine why palliative care clinicians chose to cease oxycodone-naloxone and to explore immediate and short-term benefits and harms of this medication change. Design: A consecutive cohort study. Setting: 112 adults from 13 palliative care centers. Measurements: Reasons for ceasing medication and the harms and benefits that followed this 24 and 72 hours later. Symptom burdens were summarised by the National Cancer Institute Common Terminology Criteria for Adverse Events Toxicity Gradings. Results: Combination medication was most commonly ceased because of poor pain control or impaired hepatic function. The last median oral morphine equivalent oxycodone dose before the switch was 45 mg (range 7.5-240 mg) with 76 switched to an alternative long-acting opioid (initial median oral morphine equivalent dose being 45 mg [range 5-210 mg]). Subgroup analysis of those switched because of clinicians' concerns about hepatic dysfunction demonstrated this group were receiving significantly lower opioid doses pre-cessation compared to those switched because of other reasons( p = 0.007). Regardless of why the medication was changed, improvements in pain and constipation scores were seen, the latter associated with an attendant increase in laxatives. Conclusions: This preliminary work suggests that despite theoretical concerns regarding the effect of the naloxone on opioid doses, most people were switched safely to very similar opioid doses with attendant improvements in pain control.