Ulcerative Collitis (UC) is a chronic immune-mediated inflammatory

condition of the large intestine that is frequently associated with

inflammation of the rectum but often extends proximally to involve

additional areas of the colon. The absence of rectal involvement has

been noted in fewer than 5% of adult patients with UC at diagnosis but

may be seen in up to one-third of pediatric-onset colitis. Determination of the extent and severity of disease is important to

select the appropriate treatment algorithm. Extent of the disease

should be characterized according to the Montreal classification as

proctitis (E1), left-sided colitis (E2), or extensive colitis (E3) (extension

proximal to the splenic flexure). [4,5] Commonly, severity of UC has been

classified according to the Truelove and Witts’ [6] criteria published in

1955. Mild colitis is defined as fewer than 4 bowel movements daily,

normal temperature, heart rate, hemoglobin (>11 g/dL), and ESR (<20

mm/hr). Severe disease is defined by bowel frequency greater than 6

times a day in conjunction with fever, tachycardia, anemia, or an

elevation in ESR. Tofacitinib, a JAK-STAT (Janus kinase-signal transducers and

activators of transcription) inhibitor and an anti-inflammatory drug, is a

new addition to the treatment modalities for UC. Janus kinases are

intracellular tyrosine kinases which mediate the signal transduction of

various cytokines involved in the inflammatory reactions in IBD, like IL-

6, IL-7, Il-10, IL-12, IFNα, IFNβ 2, 4, 7, 9 etc. The advantages of JAK-

STAT inhibitors over monoclonal antibodies include, the oral

administration, predictable pharmacokinetics with reduced plasma half-

life, rapid onset of action, quick clearance, lack of immunogenicity and

an intracellular target.