How do we discontinue morphine (opioid) and phenobarbital (barbiturate) in a patient?

Discontinuation of Morphine and Phenobarbital

When discontinuing morphine and phenobarbital, both medications should be tapered gradually rather than abruptly stopped to prevent withdrawal symptoms, with morphine tapered first followed by phenobarbital at a rate of 10% reduction per month for long-term users. 1, 2, 3

Morphine Discontinuation Protocol

Assessment Before Tapering

• Evaluate duration of use, current dose, and reason for discontinuation
• Assess for signs of physical dependence (tolerance may develop after several days to weeks of continued use)

Tapering Schedule for Morphine

1. Initial Reduction:

   • For patients on stable doses, begin with a 10% reduction of the total daily dose
   • Document the rationale for dose changes during the tapering process 1

2. Ongoing Reduction:

   • Continue reducing by 10% of the original dose every 1-2 weeks
   • If withdrawal symptoms occur (anxiety, muscle twitching, tremors, nausea), pause the taper and maintain the current dose until symptoms resolve 3

3. Final Stages:

   • When reaching 25% of the original dose, slow the taper to 5% reductions
   • The final steps from very low doses to zero are often the most difficult and should be the most gradual 3

Monitoring During Morphine Taper

• Use standardized scoring systems to assess pain, agitation, and respiratory distress 1
• Watch for withdrawal symptoms: anxiety, muscle twitching, tremor, weakness, dizziness, nausea, insomnia, and orthostatic hypotension 3
• If the patient receives 2 bolus doses for breakthrough symptoms in an hour, consider slowing the taper 1

Phenobarbital Discontinuation Protocol

Assessment Before Tapering

• Determine duration of use and current dose
• Recognize that physical dependence can develop, especially following prolonged use 2

Tapering Schedule for Phenobarbital

1. Standard Method:

   • Decrease the total daily dose by 30 mg per day as long as withdrawal is proceeding smoothly 2
   • For long-term users (≥1 year), use a slower taper of approximately 10% per month 4

2. Alternative Method:

   • Begin at the patient's regular dosage level
   • Decrease the daily dosage by 10% if tolerated by the patient 2

3. If Withdrawal Symptoms Appear:

   • Maintain dosage at current level or increase slightly until symptoms disappear
   • Resume tapering at a slower rate once stabilized 2

Monitoring During Phenobarbital Taper

• Minor withdrawal symptoms may appear 8-12 hours after dose reduction: anxiety, muscle twitching, tremors, nausea
• Major withdrawal symptoms (convulsions and delirium) may occur within 16 hours and last up to 5 days 2
• The intensity of withdrawal symptoms gradually declines over approximately 15 days 2

Special Considerations

Sequence of Discontinuation

• When discontinuing both medications, taper morphine first while maintaining the phenobarbital dose
• Once morphine is successfully discontinued, begin phenobarbital taper 4

Adjunctive Therapies

• Consider adjunctive medications for specific withdrawal symptoms:
  • Trazodone for insomnia
  • Gabapentin for anxiety and muscle discomfort
  • Clonidine for autonomic symptoms 4

High-Risk Scenarios

• For patients with history of seizures: taper phenobarbital more gradually (5% reduction)
• For elderly patients: use more conservative tapers due to increased sensitivity to adverse effects 4
• For patients with severe pain: ensure adequate alternative pain management before completing morphine taper 1

Follow-up and Monitoring

• Schedule frequent follow-ups (at least monthly) during the tapering process 4
• Monitor for withdrawal symptoms, emergence of underlying conditions, and suicidal ideation
• Document all dose changes and patient responses throughout the process 1

Pitfalls to Avoid

1. Abrupt discontinuation of either medication, which can lead to severe withdrawal symptoms including seizures and death 2, 3
2. Tapering too quickly, especially for long-term users
3. Failing to recognize withdrawal symptoms that indicate the need to slow the taper
4. Using a fixed taper schedule for all patients rather than individualizing based on response 4
5. Discontinuing monitoring too early (withdrawal symptoms can persist for weeks after complete discontinuation)

By following these guidelines, the discontinuation of morphine and phenobarbital can be managed safely while minimizing withdrawal symptoms and maintaining patient comfort.