Opioid rotation to oral morphine in the treatment of cancer pain not responding to transdermal fentanyl escalation

ABSTRACT

<b>Purpose</b>; Transdermal fentanyl (TF) has less systemic adverse effects as compared to morphine. However, few patients with cancer related pain obtain insufficient analgesic response despite the dose escalation of TF. The aims of this study were to describe patients with poor analgesic response and to evaluate the efficacy of opioid rotation from TF to oral morphine. <b>Case reports</b>; We conducted a retrospective chart review and analyzed six patients managed with opioid rotation in detail. Before opioid rotation, an average dose of TF was 204μg/hr. A significant decrease in pain score was found in all patients who switched to oral morphine, and five patients were treated with the combination of TF and oral morphine. <b>Conclusion</b>; These results may indicate that patients who are treated with relative high dose TF (over 200μg/hr) tended to response to poor analgesic, and opioid rotation is beneficial to restore the analgesic effects. We speculate that this clinical phenomenon is associated with opioid tolerance.