Can oxycodone (opioid analgesic) cause hallucinations and nightmares?

Oxycodone Can Cause Hallucinations and Nightmares

Yes, oxycodone can cause hallucinations and nightmares as recognized side effects, particularly as manifestations of opioid-induced neurotoxicity. 1, 2

Neuropsychiatric Side Effects of Oxycodone

• Hallucinations and nightmares are known adverse effects of oxycodone, though they occur less frequently than common side effects like constipation, nausea, and drowsiness 1, 3
• These neuropsychiatric symptoms are part of a spectrum of opioid-induced neurotoxicity that can also include delirium, cognitive impairment, and myoclonus 2
• Hallucinations with oxycodone may occur less frequently compared to morphine, as noted in comparative studies 3, 4
• Opioid-induced hallucinations can be misdiagnosed as primary psychiatric disorders if the temporal relationship with opioid use is not recognized 5

Risk Factors and Mechanisms

• Neuropsychiatric side effects are more likely to occur during:

  • Treatment initiation or dose titration phases 1
  • Rapid dose escalation 2
  • Accumulation of metabolites in patients with renal or hepatic impairment 2, 1
  • High-dose opioid therapy 1

• Oxycodone is metabolized in the liver to active metabolites including oxymorphone, which may contribute to its side effect profile 3

Management of Oxycodone-Induced Hallucinations

If hallucinations or nightmares occur with oxycodone, the following approaches should be considered:

1. Dose reduction if pain is well-controlled 1
2. Opioid rotation to a different opioid (switching to another pure agonist such as fentanyl) if hallucinations persist despite dose adjustment 1, 2
3. Rule out other causes of hallucinations or nightmares, including:
   • Metabolic disorders 1
   • Drug interactions with other medications 1
   • Underlying psychiatric conditions 5

Monitoring and Prevention

• Patients should be informed about the possibility of hallucinations and nightmares when starting oxycodone therapy 1
• Symptoms typically appear within the first few days or weeks of treatment and often resolve with continued use 1
• For patients with a history of opioid-induced neurotoxicity, closer monitoring is recommended as they are at higher risk for recurrence 2
• Patients with renal insufficiency require special caution due to potential accumulation of metabolites 2, 1

Clinical Implications

• In a study of cancer patients, switching from morphine to oxycodone resulted in statistically significant improvements in mental state for those experiencing morphine-induced delirium 6
• However, in patients specifically susceptible to opioid-induced neurotoxicity, any opioid including oxycodone can potentially cause hallucinations 2
• The incidence of hallucinations and somnolence with opioids used for cancer pain was found to be approximately 5% and 23% respectively in a Cochrane review 7

In clinical practice, recognizing the potential for oxycodone to cause hallucinations and nightmares is important for proper management. If these symptoms occur, adjusting the dose or rotating to a different opioid can often resolve the issue while maintaining adequate pain control.