Background: The semi-synthetic opioid, buprenorphine, has the general structure of morphine but differs from it in significant ways, both pharmacologically and clinically. A number of long-term studies have shown effective, long-lasting analgesia in moderate to severe cancer and non-cancer pain, including neuropathic pain, with a low incidence of constipation, nausea, dizziness and tiredness. The treatment of moderate to severe chronic pain has improved as a result of the development of new methods of administration of this substance, particularly the introduction of the transdermal drug delivery system, which offers a number of advantages over the usual oral and parenteral routes.
Scope: A panel of experts specialising in palliative care and pain treatment was convened in November 2007 to discuss their clinical experiences with transdermal buprenorphine and other analgesics. The aim was to provide practical guidance on the treatment of cancer pain with transdermal buprenorphine, particularly when there is a need for increasing pain relief leading to high and increasing doses. A literature search on the use of transdermal buprenorphine was carried out for the panel meeting (based on a search of PubMed to November 2007 - since updated by an additional search for the period to February 2009) and a number of case histories were presented and discussed. This commentary article presents this evidence and the consensus findings of the expert panel.
Findings: The Panel reached consensus that transdermal buprenorphine was a valuable treatment for chronic cancer pain, including its neuropathic components. A number of general recommendations were made. Large-scale, randomised clinical studies are needed to provide product comparisons on the use of analgesics in the treatment of neuropathic pain although it was recognised that such studies may not be practicable. Data on the treatment of acute and chronic pain should be kept separate in general. Physicians should be made more aware of the problem of hyperalgesic effects of some opioids in long term use. Buprenorphine in contrast has been described to exert an antihyperalgesic effect. The development of analgesic tolerance with some opioids in long term use and the lack of it with buprenorphine requires further studies. The registered dose range of 35-140 microg/h was considered adequate to achieve sufficient pain relief in most patients although some members of the panel presented data showing that increases beyond this dose range provided improved pain relief if slow titration is used. However, it was generally felt that more evidence was needed before this could become generally acceptable.
Conclusion: The consensus was that transdermal buprenorphine has a valuable role to play in the treatment of chronic cancer pain because of its efficacy and good safety and tolerability profile, including a low risk of respiratory depression, a lack of immunosuppression and a lack of accumulation in patients with impaired renal function.