AbstractBackground and AimsTocilizumab (TCZ; interleukine‐6 receptor antagonist) has been proposed to treat severe forms of Coronavirus disease‐19 (COVID‐19) because interleukine‐6 plays an important role in COVID‐19‐induced cytokine storm. Several clinical studies have shown very good effects of TCZ in patients with COVID‐19, with a few minor side effects reported. Only eight serious liver injuries caused by TCZ were reported before being used in the treatment of patients with COVID‐19. Considering the significantly increased use of TCZ for the treatment of COVID‐19, we would like to warn of its rare but possible serious hepatotoxicity, especially when used together with other hepatotoxic drugs.MethodsWe describe a patient with COVID‐19‐induced cytokine storm who developed drug‐induced liver injury associated with the use of TCZ.ResultsOne day after TCZ administration, serum transaminase levels increased 40‐fold. Nevertheless, TCZ had a positive effect on clinical and laboratory parameters in cytokine storm, with transaminases values normalizing in 10 days.ConclusionsThis is the first reported case of DILI caused by TCZ in a COVID‐19 patient. Intensive liver function monitoring is imperative in COVID‐19 patients, because of frequent polypharmacy with potentially hepatotoxic drugs.
