Anaesthetics, local + Alcohol and/or Antirheumatics - Drug Interactions

Limited evidence suggests that failure rate of spinal anaesthesia with bupivacaine may be markedly increased in patients whoare receiving antirheumatic drugs and/or who drink alcohol

Clinical evidence,mechanism, importance and management

The observation that regional anaesthetic failures seemed to be particularly high among patients undergoing orthopaedic surgery who were suffering from rheumatic joint diseases,prompted further study of a possible interaction. It was found that failure rate of low-dose spinal anaesthesia with 0.5 % bupivacaine (average volume of 2 mL) increased from 5 % in control group (no alcohol or long-term treatment) to 32 % to 42 % in those who had been taking antirheumatic drugs (indometacin or unspecified) for at least 6 months or who drank at least 80 g of ethanol daily, or both. The percentage of those patients who had a reduced response (i.e. an extended latency period and/or a reduced duration of action) also increased from 3 % up to 39 to 42%.(See reference number 1) The reasons are not understood. This appears to be only report of such an effect.

1. Sprotte G,Weis KH. Drug interaction with local anaesthetics. Br J Anaesth (1982) 54, 242P– 243P.