Opioid switching and rotation in primary care: implementation and clinical utility.

BACKGROUND: Opioid therapy is the standard treatment for moderate-to-severe cancer pain and is becoming a more frequent treatment for moderate-to-severe chronic noncancer pain. Response to opioids varies significantly between patients and even within the individual patient at different stages of treatment. Finding an opioid at a dose that provides adequate long-term analgesia with minimal adverse effects can be difficult. Opioid switching and opioid rotation, at different stages of therapy, represent two clinical strategies used to optimize opioid response for patients with moderate-to-severe pain.
OBJECTIVES: Review the theoretical and clinical evidence supporting the concepts of opioid switching and rotation, outline the conditions under which these practices should be considered, and briefly suggest practical steps for their implementation. SCOPE: Clinical literature, clinical practice and guideline databases, and professional society websites were searched for articles or reports describing opioid switching or opioid rotation in chronic pain therapy; variability in patient response to opioid therapy; physiologic, pharmacologic, and genetic factors that affect clinical response to opioids; and practical approaches to maximizing analgesia and minimizing adverse effects in opioid therapy. It is outside the scope of this review to evaluate the pharmacoeconomic aspects that affect changes in opioid therapy.
FINDINGS: The variability in de novo clinical response to opioids likely represents the interaction of the varying properties of the individual opioids with the variability in individual patient biology. This interaction forms the rationale for opioid switching and explains its clinical utility. As with opioid switching, success with opioid rotation is related to the myriad of factors determining an individual patient's response to a specific opioid. However, the benefits of opioid rotation also derive from a partial reversal of tolerance at the mu-opioid receptor and the response of different micro-opioid receptor subtypes to the different opioids.