JAK inhibitors are oral small molecules that interrupt the Janus kinase signalling pathway, which many inflammatory cytokines share. Because they are tablets rather than injections, they offered the first real oral alternative to biologics in rheumatoid arthritis. Regulators in the US and EU have since added warnings about cardiovascular events, blood clots, serious infection and cancer, so they are generally used after a TNF inhibitor has failed.
The facts on this page are pulled directly from official U.S. FDA datasets — they are not written from memory. Each field below names the dataset it came from, so you can check it yourself.
Plain-English summaries and drug-class explainers are written and reviewed by the Priya Life Science editorial team, led by Sreepriya Prasannan (MSc Digital Transformation of Life Sciences (Innopharma Education / Griffith College); MSc & BSc Botany). Data is retrieved automatically from the sources above and cross-checked with AI-assisted verification (Anthropic's Claude) — brand and generic names are matched against the exact FDA product record so that a combination product or a different formulation cannot be mistaken for the drug on this page. An editor reviews the result before publication. We describe this in full in our editorial standards and corrections policy. The FDA data on this page was last retrieved on 28 Aug 2026.