Immune-mediated Drug-induced Liver Injury Caused by Laninamivir Octanoate Hydrate.

We herein report the first case of immune-mediated drug-induced liver injury that may have been caused by laninamivir. A 15-year-old girl was diagnosed with influenza and prescribed 40 mg laninamivir. Six weeks later, she was admitted to our hospital because of jaundice and fatigue. Laboratory examinations revealed elevated levels of hepatobiliary enzymes, and acute liver injury was suspected. Laboratory examinations and histological findings were characteristic of autoimmune hepatitis. Steroid treatment was ineffective, and azathioprine was added to the treatment. Twenty-two months after the onset, a second biopsy revealed the absence of inflammatory infiltrations, and the drugs were withdrawn. Liver function tests remained normal nine months after withdrawal.