"Tofacitinib is an oral agent taken twice daily used to treat many rheumatological conditions mainly RA. Tofacitinib inhibits Janus kinase (JAK) signalling. Immune cells such as macrophages, monocytes and T cells play a key role in the pathophysiology of RA. They contain receptors on their surface which rely on the JAK. JAK initiates a cascade of intracellular phosphorylation events leading to the activation of transcription factor STAT. In rheumatological disease JAK-STAT signalling pathway is involved in the transcription of immune cells which promote inflammatory response."