Non‐opioid postoperative analgesia

Abstract

Although significant improvement has been made in the treatment of pain in the postoperative period, many patients still experience unnecessary discomfort resulting in distress, higher morbidity and prolonged stay in hospital. The standard pillar of postoperative treatment of severe pain is the use of opioids. However, adverse reactions to opioids make their use unfavourable. A better understanding of the pathophysiology of pain has helped clinicians to a more balanced approach to postoperative pain treatment. The development of the multimodal approach to postoperative analgesia, with the use of different drugs acting via different routes to give good analgesia, with minimal side-effects, represents a major development in the treatment of postoperative pain. Early, aggressive mobilisation and feeding must follow in order to restore normal conditions quickly. Alternatives to opioids should be used as extensively as possible. Local anaesthesia, used as regional blocks or as wound infiltration, is most beneficial. Paracetamol has good basic analgesic properties, and should probably be used in dosages higher than recommended today. The combination with a NSAID results in better and longer-lasting analgesia. The intravenous form propacetamol will increase the possibilities of its use. The new concept of selective COX-2 inhibiting NSAIDs will result in analgesic and anti-inflammatory drugs with fewer side-effects. The well-known inexpensive group of corticosteroids have good analgesic and anti-emetic properties, and are especially interesting to use in patients who do not tolerate NSAIDs. The alpha2-receptor agonists like clonidine, when administered epidurally or intrathecally, are useful adjuncts, but their adverse effects on sedation and hypotension limit their use. NMDA-receptor antagonists are of limited value in the postoperative period. Adenosine and neostigimine are still on a research level but may lead to new, clinically useful analgesic drugs. In the future, cannabinoids, cholecystokinin-receptor antagonists and neurokinin-1 antagonists may become important analgesic drugs.