A 60-year-old woman on sustained-release morphine 90 mg twice daily for cancer pain reports two to three episodes daily of sudden, intense pain lasting about 20 minutes, occurring predictably before dressing changes. Her baseline pain is well controlled. What is the MOST appropriate prescription for these episodes?

• A Increase the sustained-release morphine to 120 mg twice daily
• B A non-steroidal anti-inflammatory drug three times daily
• C Transdermal fentanyl 25 microgram/hour added to the current regimen
• D Immediate-release morphine at approximately 30 mg (one-sixth of the total daily dose) before the predictable trigger ✓

Explanation

This is predictable incident breakthrough pain. The standard rescue is immediate-release morphine at one-sixth of the total daily opioid dose, taken prophylactically before the predictable trigger. Increasing background opioid risks toxicity between episodes because the baseline control is already adequate. Fentanyl patches are unsuitable for rapid-onset episodes due to slow onset, and an NSAID does not match this incident pattern.

Reference: Oxford Textbook of Palliative Medicine, 6th ed.

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Written and medically reviewed by the StethoPrep medical team.