Cellular mechanisms of opioid tolerance and the clinical approach to the opioid tolerant patient in the post-operative period.

The high prevalence of opioid use for recreational purposes in the USA and the European Union, as well as the use of opioids for the treatment of chronic non-malignant pain, has resulted in an increase in the number of patients with opioid tolerance who undergo surgery and require post-operative pain management. The approach to post-operative pain control in these patients is significantly different to the strategies used in opioid naïve patients. Fortunately, better understanding of the cellular mechanisms of opioid tolerance in animals has resulted in the transfer of concepts from the 'bench' to the clinical arena. This chapter describes the new developments in opioid tolerance and how this knowledge can be applied to clinical practice.