Baricitinib and Upadacitinib belong to which drug class?

• A. JAK inhibitors
• B. TNF inhibitors
• C. Interleukin inhibitors
• D. Calcineurin inhibitors

Answer: (A)

Baricitinib and Upadacitinib are Janus kinase inhibitors. They are oral small molecules that block the JAK-STAT signaling pathway inside cells, which dampens the effects of several inflammatory cytokines. Baricitinib inhibits JAK1 and JAK2, while Upadacitinib is more selective for JAK1. By preventing phosphorylation of STAT proteins, these drugs reduce transcription of pro-inflammatory genes and thus help control autoimmune conditions such as rheumatoid arthritis and related diseases. They are not TNF inhibitors (which neutralize the cytokine outside cells), not specific interleukin inhibitors, and not calcineurin inhibitors (which block T-cell activation through a different pathway).