Achieving opioid-free anaesthesia

Opioids have been central to anaesthetic practice for over a century, but they risk adverse effects including postoperative nausea and vomiting (PONV), ileus, respiratory depression, and opioid-induced hyperalgesia. These complicate recovery and contribute to the wider burden of opioid misuse, a growing concern in Irish healthcare. Opioid-free anaesthesia (OFA) supports Enhanced Recovery After Surgery (ERAS) principles by removing opioid-related barriers to early mobilisation and functional recovery.

To review the rationale for OFA, how it is delivered, its limitations, and to assess how it fits into current perioperative practice in Ireland.

OFA relies on combining agents that target multiple nociceptive pathways, such as N-methyl-D-aspartate (NMDA) receptor antagonists (ketamine, magnesium), alpha-2 adrenergic agonists (especially dexmedetomidine), non-steroidal anti-inflammatory drugs (NSAIDs), paracetamol, intravenous lidocaine, and gabapentinoids. Where applicable, ultrasound-guided peripheral nerve blocks can reduce intraoperative analgesic requirements and extending postoperative analgesia. Evidence supports OFA across a range of surgical contexts. Benefits are most consistent in laparoscopic and major abdominal surgery, where faster return of bowel function, reduced length of stay, and lower rates of PONV are reported. Evidence on postoperative analgesia is less clear. Opioid consumption in the immediate post-anaesthetic period tends to be lower but is often comparable to a well-executed opioid-inclusive multimodal regimen thereafter.

Rigid opioid avoidance risks undertreating acute pain, so OFA is best applied selectively, guided by procedure type, patient comorbidities, and institutional resources. This review evaluates the rationale, implementation, and limitations of OFA, providing clinicians with a balanced appraisal of its role in modern perioperative care.