PurposeTo 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.MethodsThe 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.ResultsTwenty 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.ConclusionThe 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.

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Methadone has been known since the beginning of the 20th century. Its use for cancer pain is still controverted.Several articles clearly show the benefit of methadone for cancer pain. We attempted to identify the advantages of use of methadone early on in the course of cancer. Methadone is a very interesting molecule for cancer pain treatment because of anti NMDA, SSRI and opioid actions, lack of active metabolite, and cost. Its benefits must be balanced against the potential drug to drug interactions during treatment initiation and interactions with other drugs when methadone doses are stable. As for all opioids, side effects can appear. Ten studies including 706 patients support the use of methadone as first line opioid treatment: 7 are prospective studies (one double-blind randomized with morphine, 4 randomized controlled with morphine or transdermal fentanyl, two open studies) and 3 are retrospective studies. Seven studies support its ambulatory initiation (3 prospective including 2 controlled studies, and 4 retrospective studies) with a total of 845 patients. Methadone could be used with caution early on in cancer pain management.

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