Drug-induced thrombotic microangiopathy using the Japanese pharmacovigilance database

Objective: Thrombotic microangiopathy (T'MA), often described as thrombotic thrombocytopenic purpura (TTP) or hemolytic uremic syndrome (HUS), is clinically problematic because it is life-threatening. However, up-to-date information on drugs inducing TMA is limited in the real-world setting. The purpose of this study was to clarify drugs associated with TMA using a spontaneous reporting system database. Material and methods: We performed a retrospective pharmacovigilance disproportionality analysis using the Japanese Adverse Drug Event Report (JADER) database. Adverse event reports submitted to the Pharmaceuticals and Medical Devices Agency between 2004 and 2017 were analyzed. The drug-induced TMA, TTP, and HUS signals were estimated using disproportionality analysis with calculation of the reporting odds ratio (ROR) and 95% confidence interval (CI). Results: A total of 3,292 TMA cases were identified. In the overall analysis, approximately half of the TMA cases involved males, and the most patients were in their 60s. Signal scores of TMA were high for ticlopidine hydrochloride (ROR: 16.2, 95% CI: 12.9 - 20.5), busulfan (ROR: 15.2, 95% CI: 11.5 - 20.3), tacrolimus hydrate (ROR: 10.6, 95% CI: 9.59 - 11.8), gemcitabine hydrochloride (ROR: 10.5, 95% CI: 8.96 - 12.2), and cyclosporine (ROR: 8.70, 95% CI: 7.67 - 9.86). As for TTP or HUS, signal scores of TTP and HUS for tacrolimus and cyclosporine were similar; however, those of TTP for ticlopidine and those of HUS for gemcitabine were noteworthy, and other drugs showed varied likelihoods of reporting TTP and HUS. Conclusion: Our results should raise physicians' awareness of drugs associated with TMA, but further investigation of these medications is warranted.