BACKGROUND: Following laparoscopic cholecystectomy, an effective post-operative pain control is necessary, at least during the first 24 hours. We present a randomized, double-blind trial on the effect of the combined use of intravenous parecoxib, and metamizol or paracetamol on piritramide consumption using a patient-controlled analgesia (PCA) pump in patients recovering from laparoscopic cholecystectomy. METHODS: 120 patients were randomly allocated to four patient groups treated with normal saline or one of non-opioid analgesics (parecoxib 40 mg twice daily, metamizol 1 g three times daily, paracetamol 1 g three times daily) in addition to piritramide using the PCA pump. Beginning in the post-anesthesia care unit (PACU), patients were asked every 2 h for 6 hours and afterwards once every 6 h to quantify their pain experience at rest while piritramide consumption was recorded. RESULTS: In all groups, piritramide consumption was high in PACU. Only metamizol significantly reduced piritramide consumption compared to the others upon discharge from PACU. Overall, cumulative piritramide consumption was slightly lower in the metamizol group and higher in the NaCl group; however, these findings were statistically not significant. VAS scores were highest upon arrival in PACU and dropped almost continuously after surgery. A significantly lower postoperative pain intensity was only found in the parecoxib group at 24 h after surgery compared to the metamizol group. CONCLUSION: The efficacy of tested additive medications on piritramide consumption and pain relief is weak and there is no clear-cut difference between the non-opioid drugs used.