Practical management of opioid rotation and equianalgesia.

PURPOSE

To review the recent literature on opioid rotation (ie, switching from one opioid drug to another or changing an opioid's administration route) in cancer patients experiencing severe pain and to develop a novel equianalgesia table for use in routine clinical practice.

METHODS

The MEDLINE database was searched with terms "cancer pain," "opioid rotation," "opioid switching," "opioid ratio," "opioid conversion ratio," and "opioid equianalgesia" for the major opioids (morphine, oxycodone, fentanyl, and hydromorphone) and the intravenous, subcutaneous, oral, and transdermal administration routes. Selected articles were assessed for the calculated or cited opioid dose ratio, bidirectionality, and use of the oral morphine equivalent daily dose or a direct drug-to-drug ratio.

RESULTS

Twenty publications met our selection criteria and were analyzed in detail. We did not find any large-scale, prospective, double-blind randomized controlled trial with robust design, and most of the studies assessed relatively small numbers of patients. Bidirectionality was investigated in seven studies only.

CONCLUSION

The updated equianalgesic table presented here incorporates the latest data and provides information on bidirectionality. Despite the daily use of equianalgesic tables, they are not based on high-level scientific evidence. More clinical research is needed on this topic.