Background: Opioid rotation is currently the subject of considerable debate for two reasons: firstly as a strategy for pain treatment, and secondly because of the difficulty in determining equianalgesic doses. Switching from one slow-release (SR) opioid analgesic to another raises a number of critical issues, and there are no widespread studies that support a standard protocol. Initiation of opioid therapy must consider gradual dose titration of the drug until the minimum effective and maximum tolerated dosage for each patient is found.
Objective: This study aimed to evaluate the effects of SR opioid rotation after a stabilization period with normal-release (NR) morphine ('start therapy') in patients with cancer or non-cancer pain not controlled with their current SR opioid.
Methods: This is a multicentre, open-label, prospective study. A total of 326 consecutive patients were enrolled who were affected by chronic cancer or non-cancer pain that was not controlled by an SR opioid administered as either monotherapy or in combination with other analgesic drugs. Following start therapy with oral NR morphine at a dosage of 5 mg or 10 mg every 4 hours, rotation to an SR opioid of a different type from that previously administered was carried out.
Results: After about 3 days of start therapy with NR morphine, rotation to an SR opioid allowed a significant decrease of both baseline pain and daily episodes of breakthrough pain. No significant difference was detected between dosages and type of opioid administered, both prior to and after the start therapy period with NR morphine.
Conclusions: Rotation to another opioid preceded by a brief period of opioid receptor resetting by start therapy with NR morphine allows a good level of pain control and avoids rotation to inappropriate opioid dosages or combinations analgesics.