Lignocaine plus morphine in bolus patient-controlled intravenous analgesialacks post-operative morphine-sparing effect

Lignocaine has been used successfully to treat burn pain and neuropathic pa in. We have conducted a randomized, double-blind trial to assess the morphi ne-sparing effect of intravenous lignocaine in patients with acute pain. Af ter major abdominal surgery, patients were treated with post-operative pati ent-controlled intravenous analgesia in two groups: group M (n = 25, morphi ne 0.2 mg mL(-1)) and group ML (n = 25, morphine 0.2 mg mL(-1) plus lignoca ine 3.2 mg mL(-1)). The patient-controlled analgesia system was programmed to deliver a 5 mL bolus with a 50 mL per 4 h limit; the lockout time was 10 min. Both groups closely resembled each other in terms of demographic data , pain intensity, cumulative morphine dose and the morphine-associated naus ea, vomiting and pruritus. However, the sedation scores in group ML patient s during the first post-operative day were significantly greater than those in group M. The incidence of lignocaine-related lightheadedness and dry mo uth was also significantly greater in group ML than in group M. It was conc luded that the addition of lignocaine 3.2 mg mL(-1) to morphine 0.2 mg mL(- 1) given via patient-controlled analgesia system does not provide a post-op erative morphine-sparing analgesic effect.