Can morphine be given in common bile duct (CBD) dilation?

Morphine Use in Common Bile Duct Dilation

Morphine should be avoided in patients with common bile duct (CBD) dilation due to its ability to cause spasm of the sphincter of Oddi, which can worsen biliary obstruction and potentially lead to increased morbidity.

Mechanism of Action and Effects on Biliary System

Morphine has specific effects on the biliary system that make it problematic in CBD dilation:

• Morphine causes spasm of the sphincter of Oddi, as explicitly stated in the FDA drug label: "Morphine sulfate injection may cause spasm of the sphincter of Oddi and diminish biliary and pancreatic secretions" 1
• This sphincter spasm leads to measurable constriction of the common bile duct, with research showing significant reduction in CBD diameter after morphine administration 2
• The constriction effect is rapid, with studies demonstrating CBD diameter reduction from 9.5mm to 5.8mm within 8 minutes of IV morphine administration 2

Clinical Implications in CBD Dilation

When CBD is already dilated, administering morphine can:

1. Exacerbate biliary obstruction
2. Increase biliary pressure
3. Potentially worsen existing pathology
4. Complicate diagnostic workup

Management Recommendations for CBD Dilation

The 2017 British Society of Gastroenterology (BSG) guidelines on common bile duct stones management provides relevant guidance:

1. Diagnostic approach: Patients with suspected CBD stones should undergo transabdominal ultrasound and liver function tests initially 3
2. Therapeutic considerations: If CBD stones are confirmed, stone extraction should be offered, with evidence of benefit being greatest for symptomatic patients 3
3. Procedural considerations: For patients requiring ERCP:
   • Rectal NSAIDs (diclofenac or indomethacin 100mg) should be administered to reduce post-ERCP pancreatitis risk 3
   • Consider pancreatic stent placement in high-risk cases 3
   • Coagulation status should be assessed and managed appropriately 3

Alternative Pain Management Options

For patients with CBD dilation requiring pain management:

• Non-opioid analgesics should be first-line
• If opioids are necessary, consider alternatives to morphine that have less effect on the sphincter of Oddi
• For procedural sedation during ERCP, propofol-assisted sedation has been shown to be safe and effective 3

Special Considerations

• Diagnostic imaging: Morphine has historically been used in some hepatobiliary imaging protocols to increase biliary pressure, but this practice has limitations and can lead to false-negative results 4
• Narcotic substitution: Long-term narcotic use (including methadone and buprenorphine) has been associated with asymptomatic CBD dilation in 8.3% of patients 5
• Coexisting conditions: Use morphine with caution in patients with severe renal or hepatic impairment, as noted in the FDA label 1

Conclusion

The evidence clearly demonstrates that morphine causes sphincter of Oddi spasm and CBD constriction. In patients with existing CBD dilation, morphine administration could worsen biliary obstruction and lead to increased morbidity. Alternative pain management strategies should be employed in these patients.