Upadacitinib is an oral selective inhibitor of Janus associated kinase 1 (JAK-1) that is used in the therapy of moderate-to-severe rheumatoid arthritis. Upadacitinib has been associated with a low rate of serum enzyme elevations during therapy, but has not been linked to cases of clinically apparent acute liver injury although it may pose a risk for reactivation of hepatitis B in susceptible patients.