To investigate the combined analgesic and spasmolytic effect of dipyrone, 104 patients suffering from "severe" or "excruciating" colic pain due to a confirmed calculus in the upper urinary tract were randomized to receive i.v. either 2.5 g dipyrone (36 patients), 100 mg tramadol (35 patients), or 20 mg butylscopolamine (33 patients) in a multicentre, observer-blind, parallelgroup study conducted in 8 German centres. The three treatment groups were homogeneous when analyzed by age, sex, height, and baseline pain intensity. Dipyrone was significantly more effective than tramadol in reducing pain for the primary endpoint, pain intensity differences (PID) at 20, 30, and 50 min after drug administration, and was significantly more effective than butylscopolamine at 30 and 50 min for the secondary efficacy endpoint, pain intensity differences on a categorical scale. Dipyrone had the highest SPID0_ 2 h of the three drugs (P < 0.05). Only 5 patients receiving dipyrone needed "rescue" medication as compared with 13 patients given tramadol and 11 patients receiving butylscopolamine. Adverse events were observed in 4 patients receiving butylscopolamine and in 1 patient each given dipyrone and tramadol. "Distinct" pain relief as assessed on a visual analogue scale (VAS) is a reliable method of determining the onset of analgesic action in the colic pain model.
The pyrazolone derivative dipyrone (metamizol) is one of the most widely used drugs throughout the world because of its potent analgesic and antipyretic properties. Since this drug also exhibits a pronounced spasmolytic effect, it is recommended as a first-line drug in the treatment of acute colic pain [1,2].
Although there is substantial evidence that dipyrone also has a pronounced spasmolytic effect, the clinical impact of its combined mode of action has not been investigated. Therefore, we decided to compare dipyrone (Novalgin) with tramadol (Tramal), a pure analgesic and centrally acting opioid, and butylscopolamine (N-butylscopo-Correspondence to: Dr. G. Stankov lamonium bromide, Buscopan), an alkaloid with pure spasmolytic and parasympatholytic properties, in the treatment of acute renal colic pain. Both comparative drugs are widely used either as monotherapy or in combination in this condition [3][4][5].
The present study was performed as a double-blind (observer-blind), randomized, multicentre, parallel-group study in patients suffering from acute colic pain due to renal or ureteral calculus. The primary objectives of the trial were to assess the therapeutic effect of dipyrone and the two comparative drugs on acute colic pain using a visual analogue scale and a categorical five-point scale.