A narrative review on tofacitinib: The properties, function, and usefulness to treat coronavirus disease 2019.

In coronavirus disease 2019 (COVID-19), the formation of cytokine storm may have a role in worsening of the disease. By attaching the cytokines like interleukin-6 to the cytokine receptors on a cell surface, Janus kinase (JAK)-signal transducers and activators of transcription (STAT) pathway will be activated in the cytoplasm lead to hyperinflammatory conditions and acute respiratory distress syndrome. Inhibition of JAK/STAT pathway may be useful to prevent the formation of cytokine storm. Tofacitinib is a pan inhibitor of JAKs. In this review, the main characteristics of tofacitinib and its usefulness against COVID-19 pneumonia were reviewed. Tofacitinib may be a hopeful therapeutic candidate against COVID-19 respiratory injury since it inhibits a range of inflammatory pathways. Hence, the agent may be considered a potential therapeutic against the post-COVID-19 respiratory damage. Compared to other JAK inhibitors (JAKi), the administration of tofacitinib in COVID-19 patients may be safer and more effective. Other JAKi such as baricitinib are related to severe adverse events such as thrombotic events compared to more common side effects of tofacitinib.