Oral Fluoroquinolone Use and the Risk of Acute Liver Injury: A Nationwide Cohort Study

BACKGROUND: Antibiotics are considered to be among the most frequent causes of drug-related acute liver injury (ALI). Although many ALIs have mild and reversible clinical outcomes, there is substantial risk of severe reactions leading to acute liver failure, need for liver transplant, and death. Recent studies have raised concerns of hepatotoxic potential related to the use of fluoroquinolones. METHODS: This study examined the risk of ALI associated with oral fluoroquinolone treatment compared with amoxicillin (419 930 courses, propensity score matched 1:1). The information on drug use was collected from a national, registry-based cohort derived from all Swedish adults aged 40–85 years. RESULTS: During a follow-up period of 60 days, users of oral fluoroquinolones had a >2-fold risk of ALI compared to users of amoxicillin (hazard ratio, 2.32 [95% confidence interval {CI}, 1.01–5.35). The adjusted absolute risk difference for use of fluoroquinolones as compared to amoxicillin was 4.94 (95% CI, .04–16.3) per 1 million episodes. CONCLUSIONS: In this propensity score–matched study, fluoroquinolone treatment was associated with an increased risk of ALI in the first 2 months after starting treatment.