The intraoperative use of non-opioid adjuvant analgesic agents: a survey of anaesthetists in Australia and New Zealand

BACKGROUND: Opioids have long been the mainstay of drugs used for intra-operative analgesia. Due to their well-known short and long term side effects, the use of non-opioid analgesics has often been encouraged to decrease the dose of opioid required and minimise these side effects. The trends in using non-opioid adjuvants among Australian Anaesthetists have not been examined before. This study has attempted to determine the use of non-opioid analgesics as part of an opioid sparing practice among anaesthetists across Australia and New Zealand. METHODS: A survey was distributed to 985 anaesthetists in Australia and New Zealand. The questions focused on frequency of use of different adjuvants and any reasons for not using individual agents. The agents surveyed were paracetamol, dexamethasone, non-steroidal anti-inflammatory agents (NSAIDs), tramadol, ketamine, anticonvulsants, intravenous lidocaine, systemic alpha 2 agonists, magnesium sulphate, and beta blockers. Descriptive statistics were used and data are expressed as a percentage of response for each drug. RESULTS: The response rate was 33.4%. Paracetamol was the most frequently used; with 72% of the respondents describing frequent usage (defined as usage above 70% of the time); followed by parecoxib (42% reported frequent usage) and dexamethasone (35% reported frequent usage). Other adjuvants were used much less commonly, with anaesthetists reporting their frequent usage at less than 10%. The majority of respondents suggested that they would never consider dexmedetomidine, magnesium, esmolol, pregabalin or gabapentin. Perceived disincentives for the use of analgesic adjuvants varied. The main concerns were side effects, lack of evidence for benefit, and anaesthetists’ experience. The latter two were the major factors for magnesium, dexmedetomidine and esmolol. CONCLUSION: The uptake of tramadol, lidocaine and magnesium amongst respondents from anaesthetists in Australia and New Zealand was poor. Gabapentin, pregabalin, dexmedetomidine and esmolol use was relatively rare. Most anaesthetists need substantial evidence before introducing a non-opioid adjuvant into their routine practice. Future trials should focus on assessing the opioid sparing benefits and relative risk of using individual non-opioid adjuvants in the perioperative period for specific procedures and patient populations.