Dipyrone overdose.

Background: Dipyrone is a pyrazolone derivative used as an analgesic and antipyretic. Agranulocytosis, dipyrone's most serious and potentially fatal adverse effect, has led to its withdrawal in several countries. However, agranulocytosis is subject to geographical variability, ratio with at risks ranging from 0.8-23.7. In many countries dipyrone is still widely used in adults and children and even as an over-the-counter (OTC) preparation. Information on the effects of dipyrone overdose is scanty.

Objective: To determine the demographic and clinical characteristics of dipyrone overdose.

Methods: Retrospective review of prospectively collected poison center data on acute exposure to dipyrone over a three-year period. The data were subjected to descriptive analysis. Mann-Whitney test and Chi-square analysis were performed where relevant.

Results: A total of 243 records met the inclusion and exclusion criteria. Median age was 17y (4m-83y), median amount 5 g (250 mg-45 g), and median time to consultation was 2 h (5 min-48 h). Toxic events (49) occurred in 39 (16%) patients; 57% of these were gastrointestinal and all were mild. Time to consultation was longer in the symptomatic patients (4 h vs. 1.5 h, respectively, p=0.001) and in children (8 h vs. 3.5 h in adults). Suicidal patients ingested significantly larger amounts (8 g vs. 3.7 g, respectively, p=0.001), as did patients with gastrointestinal symptomatology (7.5 g vs. 5 g in asymptomatics, p=0.001). No agranulocytosis was reported.

Discussion: Dipyrone overdose is associated with mild, mainly gastrointestinal toxicity; this was noted at a median dose of 7.5 g. Early gastrointestinal decontamination may have prevented toxicity. The suggested treatment includes gastrointestinal decontamination (if <1 h since ingestion) and supportive measures.