Can you give Oramorph (morphine) in cirrhosis?

Morphine Use in Cirrhosis: Considerations and Recommendations

Morphine can be used in patients with cirrhosis, but requires dose reduction and careful monitoring due to altered pharmacokinetics and increased risk of adverse effects. 1

Pharmacokinetic Changes in Cirrhosis

• Morphine metabolism is significantly altered in cirrhotic patients:
  • Half-life increased approximately 2-fold 1
  • Bioavailability increased 4-fold (68% vs 17% in healthy individuals) 1
  • Decreased intrinsic hepatic clearance 2
  • Over 90% is excreted via the kidneys after liver metabolism 1

Dosing Recommendations

1. Initial dosing:

   • Start with 50% of the normal dose 2
   • Increase dosing interval by 1.5 to 2-fold 2
   • Monitor closely for signs of respiratory depression, sedation, and hypotension 2

2. Administration route considerations:

   • Oral administration (Oramorph) has significantly increased bioavailability in cirrhosis 1, 2
   • IV administration may provide more predictable effects but still requires dose reduction 1

Monitoring Requirements

• Vigilant monitoring for:
  • Respiratory depression (primary risk) 2
  • Excessive sedation 3
  • Hepatic encephalopathy 1, 4
  • Constipation (can precipitate hepatic encephalopathy) 4
  • Worsening liver function 3

Specific Precautions

• Constipation management is critical:

  • Implement prophylactic bowel regimen 3, 4
  • Constipation can increase ammonia production and precipitate hepatic encephalopathy 4

• Avoid in:

  • Severe hepatic impairment (insufficient safety data) 2
  • Patients with high risk of hepatic encephalopathy 1, 4

Alternative Analgesics

• For mild pain:

  • Acetaminophen at reduced doses (2-3g/day maximum) is first-line 3, 5

• For moderate-severe pain when morphine is contraindicated:

  • Fentanyl (pharmacokinetics less affected by liver disease) 1, 3, 6
  • Hydromorphone (more stable half-life in liver dysfunction) 1, 3

• Avoid:

  • NSAIDs (risk of GI bleeding, decompensation, nephrotoxicity) 3, 5
  • Codeine (contraindicated due to risk of respiratory depression) 1, 3
  • Oxycodone (unpredictable metabolism, increased respiratory depression) 1
  • Tramadol (increased bioavailability, seizure risk) 1, 3

Common Pitfalls

• Overreliance on opioids: Studies show cirrhotic patients often receive more opioids and fewer non-opioid analgesics than non-cirrhotic patients 7
• Inadequate constipation prevention: Failure to implement prophylactic bowel regimens can lead to hepatic encephalopathy 4
• Insufficient monitoring: Patients with cirrhosis require more frequent assessment for adverse effects 3, 2
• Prolonged use: Opioid use should be limited to short-acting agents for short duration when possible 5

By following these guidelines, morphine (Oramorph) can be used with appropriate caution in cirrhotic patients, with careful dose adjustment and vigilant monitoring for adverse effects.