Is lorazepam (Ativan) safe for sedation in patients with myotonic dystrophy?

Lorazepam in Myotonic Dystrophy: Safety Considerations for Sedation

Lorazepam should be avoided for sedation in patients with myotonic dystrophy due to significant risk of respiratory depression and potential respiratory arrest.

Risks of Benzodiazepines in Myotonic Dystrophy

Patients with myotonic dystrophy have several characteristics that make them particularly vulnerable to respiratory complications when receiving sedatives:

• Trunk and respiratory muscle weakness is common in myotonic dystrophy 1
• Increased sensitivity to respiratory depressant effects of sedatives
• Risk of prolonged or unexpected respiratory depression
• Case reports document respiratory arrest with benzodiazepines in these patients 2

The American College of Chest Physicians (ACCP) consensus statement specifically notes that patients with neuromuscular disorders like myotonic dystrophy are "especially vulnerable to the adverse physiologic effects of general anesthesia and procedural sedation" 3. This vulnerability includes:

• Weak upper airway dilator muscles
• Limited mobility of mandible and cervical spine
• Decreased functional residual capacity
• Risk of rapid deterioration in gas exchange

Safer Alternatives for Sedation

For patients with myotonic dystrophy requiring sedation, consider these safer approaches:

1. Total intravenous anesthesia with short-acting agents:

   • Propofol and remifentanil have been used successfully 4
   • Short duration of action allows for better control and faster recovery

2. Combined regional-general approach:

   • Epidural anesthesia combined with minimal general anesthesia can reduce respiratory depression risk 4
   • Allows for reduced dosing of systemic sedatives

3. Respiratory monitoring and support:

   • Continuous SpO2 monitoring is essential
   • End-tidal CO2 monitoring when possible
   • Have non-invasive positive pressure ventilation (NPPV) immediately available

Special Precautions if Sedation is Absolutely Necessary

If sedation cannot be avoided:

• Preoperative assessment:

  • Measure FVC, MIP, MEP, and PCF to quantify respiratory function 3
  • Consider patients with FVC <50% predicted at increased risk
  • Consider patients with FVC <30% predicted at high risk

• Procedural setting:

  • Perform sedation with an anesthesiologist present
  • Have immediate access to airway management equipment
  • Consider ICU setting for post-procedure monitoring

• Post-procedure management:

  • Monitor for prolonged respiratory depression
  • Have mechanical cough assistance available
  • Consider extubation directly to NPPV for high-risk patients 3

Conclusion

The documented case of respiratory arrest following diazepam administration in a patient with myotonic dystrophy 2 and the ACCP consensus recommendations strongly suggest avoiding benzodiazepines like lorazepam for sedation in these patients. Alternative approaches using short-acting agents with minimal respiratory depression effects, combined with appropriate monitoring and respiratory support, provide safer options for necessary procedures.