LAUSR

Peripheral nerve blocks effectively alleviate postoperative pain. Animal studies and human research suggest that opioid tolerance may reduce the effectiveness of local analgesics. The reduced effectiveness has been observed in opioid‐tolerant humans and animals undergoing spinal and infiltration anaesthesia with both lidocaine and bupivacaine. However, the impact on peripheral nerve blocks in humans has not been evaluated. This study aims to assess the onset time and duration of a radial nerve block in opioid‐tolerant individuals compared to opioid‐naive individuals. We hypothesise that peripheral nerve blocks may be less effective in producing sensory and motor blockades in opioid‐tolerant individuals compared to their opioid‐naive counterparts.