Perioperative opioids: a narrative review contextualising new avenues to improve prescribing.

Opioids have dominated the management of perioperative pain in recent decades with higher doses than ever before used in some circumstances. Through the expanding use of opioids, growing research has highlighted their associated side-effects and the intertwined phenomena of acute withdrawal syndrome, opioid tolerance, and opioid-induced hyperalgesia. With multiple clinical guidelines now endorsing multimodal analgesia, a diverse array of opioid-sparing agents emerges and has been studied to variable degrees, including techniques of opioid-free anaesthesia. It remains unclear to what extent such methods should be adopted, yet current evidence does suggest dependence on opioids as the primary perioperative analgesic might not meet the principles of 'rational prescribing' as described by Maxwell. In this narrative review we describe how, using current evidence, a patient-centred rational-prescribing approach can be applied to opioids in the perioperative period. To contextualise this approach, we discuss the historical adoption of opioids in anaesthesia, our growing understanding of associated side-effects and emerging strategies of opioid-sparing and opioid-free anaesthesia. We discuss avenues and challenges for improving opioid prescribing to limit persistent postoperative opioid use and how these may be incorporated into a rational-prescribing approach.