Risk of Acute Liver Injury Associated With the Combination of Amoxicillin and Clavulanic Acid

Abstract

They were 35 cases of idiopathic acute liver injury. None was fatal. There were 14 cases of acute liver injury among users of amoxicillin alone. The type of liver injury was hepatocellular in half the cases. There were 21 cases of acute liver injury among users of amoxicillin and clavulanic acid together. The type of liver injury was cholestatic in three quarters of the cases. The incidence rates and 95% confidence intervals (CIs) of developing acute liver injury associated with the combination of amoxicillin and clavulanic acid and amoxicillin alone were 1.7 (1.1-2.7) and 0.3 (.02-0.5) per 10 000 prescriptions, respectively. The rate ratios and 95% CIs of acute liver injury for amoxicillin and clavulanic acid together compared with amoxicillin alone were 6.3 (3.2-12.7) for all patients and 8.4 (3.6-20.8) for patients presenting with jaundice. Among users of amoxicillin and clavulanic acid together, the risk of developing acute liver injury was more than 3 times greater after a course of 2 or more consecutive prescriptions than after a single course of therapy. The risk also increased with age among users of amoxicillin and clavulanic acid together. The combination of advancing age and repeated prescriptions resulted in a risk of developing acute liver injury greater than 1 per 1000 users of amoxicillin and clavulanic acid together.