The effect of metamizole on gastric emptying and small intestine transit in the rat

: The effect of the pyrazolone derivative metamizole on the motility of the upper gastrointestinal tract of the rat was investigated. An animal model for simultaneous quantification of gastric emptying and small intestinal transport was used. A test meal with different radioactive labels was administered by means of previously implanted tubes both to the stomach (1.0 ml; 51Cr) and to the duodenum (0.25 ml; 99mTc), and the spatial distribution of both isotopes in a gastrointestinal preparation was determined after a transport time of 30 min. It has been shown that intravenously administered metamizole reduces significantly the percentage of the test meal discharged by the stomach (control: 70.9 +/- 2.8; 50 mg/kg metamizole: 26.3 +/- 6.9, p less than 0.001; 250 mg/kg metamizole: 3.8 +/- 1.5, p less than 0.001); 1250 mg/kg metamizole: 1.1 +/- 0.3; p less than 0.001). The 50- and 250-mg/kg doses had no negative effect on the propulsion of the small intestine. A dose of 1250 mg/kg induced a significant reduction in small intestinal transport (p less than 0.001).