Correspondence (letter to the editor): Metamizole Has Been Overlooked as a Trigger for Acute Liver Injury and Acute Liver Failure

We read the article by Weiler et al. on the epidemiology of acute liver failure (ALF) in Germany with great interest (1). The article clearly illustrates that the rates at which substances cause drug-induced liver injury (DILI) differ in the international comparison. The authors showed that phenprocoumon is a relatively common cause of ALF in Germany, whereas American registry studies of DILI do not make any mention of phenprocoumon, probably because of the more common use of warfarin (2). Furthermore, awareness of potential hepatotoxicity is vital for recognizing and notifying this condition. In this context we wish to mention our case series of 23 patients with severe icteric hepatitis owing to metamizole intake, with metamizole a contributing causal factor in two cases of ALF (3). Liver injury has thus far not been included in the adverse effects for metamizole. Except for our study, only individual case reports of liver injury after metamizole administration exist (4). The study reported by Weiler et al. does not identify metamizole as a triggering medication either, which we explain with lacking awareness regarding liver injury due to metamizole, with consequently lacking reporting of cases. The medicines report regarding metamizole in the same issue of Deutsches Ärzteblatt calls for documenting in detail the perioperative use of metamizole in the discharge notes, to enable those in charge of subsequent treatment to recognize the signs of agranulocytosis early on. On the basis of our study, this also holds true for categorizing acute icteric hepatitis or acute liver failure after an inpatient stay and use of metamizole.