Comparison of the onset and duration of the analgesic effect of dipyrone, 1 or 2 g, by the intramuscular or intravenous route, in acute renal colic.

In a double-blind, double-dummy randomized controlled clinical trial, the onset and duration of the analgesic effect of dipyrone, 1 or 2 g, and diclofenac sodium, 75 mg, by either the i.m. or the i.v. route were compared in 293 patients (aged 18-70 years) with acute renal colic. A level of > or = 50 mm on the 100-mm visual analogue scale was required for inclusion in the study. Patients were randomly allocated to six treatment groups, receiving dipyrone 1 g i.m., dipyrone 1 g i.v., dipyrone 2 g i.m.;, dipyrone 2 g i.v., diclofenac sodium 75 mg i.m.; and diclofenac sodium 75 mg i.v., respectively. Evaluations were performed at 10, 20, 30, and 60 min and 2, 4, and 6 h after treatment (time 0). Primary efficacy end points included course of pain, total pain, percentage of patients with a pain improvement of 50% or more at each evaluation time, pain intensity evaluated by the investigator on a 0-3 scale, and differences in pain intensity. The analgesic response was more marked and prolonged among patients receiving dipyrone 2 g i.m. or dipyrone 2 g i.v. There were no significant differences between dipyrone 1 g and diclofenac sodium 75 mg, by either the i.m. or the i.v. route. All treatment regimens were well tolerated.