Untersuchungen zum differenzierten Einsatz von Nichtopioiden zur postoperativen Analgesie I - Quantifizierung des analgetischen Effektes von Metamizol mittels der patientenkontrollierten Analgesie

OBJECTIVE: The aim of this study was to investigate: 1. Whether the perioperative administration of metamizol causes a significant reduction in postoperative opioid requirements within the first 24 h after surgery. 2. The opioid-sparing effect after different types of operations. 3. Whether preoperative application of metamizol causes a significant reduction of the pain-score immediately after operation. METHODS: In a double-blind, randomised, placebo-controlled study, 117 patients, scheduled for minor orthopaedic or laparoscopic surgery or other operations (mainly resection of the thyroid gland and inguinal herniotomies) received either metamizol (1 g/100 ml NaCl 0.9%) or placebo (100 ml NaCl 0.9%) intravenously over 15 min in three separate doses: the first dose was given just before induction and the others 6 h and 12 h later. After surgery all patients were allowed to self-administer buprenorphine from a PCA (patient-controlled analgesia) pump (Bolus: 30 microgram, lockout: 5 min in the recovery room, 30 min on the ward). Every hour for the first 6 h and after 24 h, cumulated doses of buprenorphine, pain scores (0-10), blood pressure, pulse and side effects were recorded. RESULTS: After minor orthopaedic and laparoscopic surgery, metamizol-treated patients had significantly less pain immediately after surgery and used a significantly lower cumulated dose of opioid in the first 24 h after surgery (-20% and -67% respectively) than patients receiving placebo. After the other types of surgery no analgesic effect could be established. CONCLUSIONS: Perioperative administration of metamizol results in better pain relief and significantly lower buprenorphine requirements particularly after laparoscopic operations. To achieve a significant pain reduction immediately after the operation, the first dose should be applied before induction.