Upadacitinib belongs to a class of drugs called Janus kinase (JAK) inhibitors. Upadacitinib is used to treat a number of autoimmune disorders such as rheumatoid arthritis, psoriatic arthritis, eczema... Learn basic information such as indications, contraindications, dosage and side effects of the drug. Upadacitinib drug will help patients improve treatment results.