Efficacy and tolerance of metamizole versus morphine for acute pancreatitis pain.

BACKGROUND/AIMS: Morphine has been contraindicated for pain treatment in acute pancreatitis because of its presumed opioid-induced sphincter of Oddi dysfunction. However, scientific evidence supporting a deleterious influence on the clinical course is absent. This pilot study was undertaken to evaluate the efficacy and adverse events of metamizole versus morphine in acute pancreatitis.

METHODS

16 patients with acute pancreatitis were randomized to receive 10 mg/4 h s.c. (n = 8) morphine or 2 g/8 h i.v. (n = 8) metamizole. Pain scores were recorded every 4 h during 48 h after admission by a Visual Analogue Scale. Pethidine was additionally administered as a rescue therapy.

RESULTS

75% of patients achieved pain relief in the metamizole group versus 37.5% in the morphine group within 24 h of hospitalization (6/8 vs. 3/8; p: n.s.). The mean time to achieve pain relief was shorter in the metamizole group (10 +/- 6.6 vs. 17 +/- 18.3 h; p: n.s.). At the end of the study, 75% of patients achieved pain relief in the metamizole group versus 50% in the morphine group. Three patients in each group needed pethidine: 2 out of 3 achieved pain control in the metamizole group vs. 0 out of 3 in the morphine group.

CONCLUSIONS

Intravenous metamizole shows a non-significant association with a quicker pain relief than morphine s.c. in acute pancreatitis. A larger randomized controlled trial should be desirable to confirm this result. and IAP.