Tofacitinib

What it is and how it works

Mechanism of Action Tofacitinib is a Janus kinase (JAK) inhibitor. JAKs are intracellular enzymes which transmit signals arising from cytokine or growth factor-receptor interactions on the cellular membrane to influence cellular processes of hematopoiesis and immune cell function. Within the signaling pathway, JAKs phosphorylate and activate Signal Transducers and Activators of Transcription (STATs) which modulate intracellular activity including gene expression. Tofacitinib modulates the signaling pathway at the point of JAKs, preventing the phosphorylation and activation of STATs.

Indications

Tofacitinib tablets are Janus kinase (JAK) inhibitors. Tofacitinib tablets are indicated for the treatment of adult patients with: Moderately to severely active rheumatoid arthritis (RA), who have had an inadequate response or intolerance to one or more TNF blockers. Active psoriatic arthritis (PsA), who have had an inadequate response or intolerance to one or more TNF blockers. Active ankylosing spondylitis (AS), who have had an inadequate response or intolerance to one or more TNF blockers. Moderately to severely active ulcerative colitis (UC), who have had an inadequate response or intolerance to one or more TNF blockers. Tofacitinib tablets are indicated for the treatment of pediatric patients 2 years of age and older with: Active PsA, who have had an inadequate response or intolerance to one or more TNF blockers. Active polyarticular course juvenile idiopathic arthritis (pcJIA), who have had an inadequate response or intolerance to one or more TNF blockers.

Dosage and administration (summary)

Recommended Evaluations and Immunization Prior to Treatment Initiation Prior to initiating tofacitinib tablets, consider performing an active and latent TB evaluation, viral hepatitis screening, a complete blood count, and updating immunizations. Avoid tofacitinib tablets initiation if absolute lymphocyte count <500 cells/mm 3 , an absolute neutrophil count (ANC) <1000 cells/mm 3 or hemoglobin <9 g/dL. Important Administration Instructions XELJANZ XR (extended-release tablets) is not substitutable with tofacitinib tablets. Switching between tofacitinib tablets and XELJANZ XR should be made by the healthcare provider.

Contraindications

None. None.

Warnings and precautions

Serious Infections: Avoid use of tofacitinib tablets during an active serious infection, including localized infections. Gastrointestinal Perforations: Promptly evaluate patients at increased risk for gastrointestinal perforation who present with new onset abdominal symptoms. Hypoglycemia in Patients with Diabetes: Consider increased monitoring of blood glucose; advise patients with diabetes to notify their healthcare provider if they develop signs or symptoms of hypoglycemia.

Pregnancy

Pregnancy Risk Summary The available data with tofacitinib tablets from a pregnancy exposure registry that enrolled 11 exposed pregnant females, pharmacovigilance, and published literature are insufficient to draw conclusions about a drug-associated risk of major birth defects, miscarriage, or other adverse maternal or fetal outcomes.

Storage and supply

How Supplied Information for Tofacitinib Tablets How supplied information for tofacitinib tablets is shown in Table 23. Table 23: How Supplied Information for Tofacitinib Tablets Dosage Form, Strength, and Description Bottle Size (number of tablets) NDC Number Tofacitinib 5 mg tablets White to off white colored, round shaped, biconvex, film-coated …

Source: Tofacitinib (Tofacitinib) — US FDA prescribing information, 2026-09-01, DailyMed. Summarised and shortened; the full label governs. Iranian registration, indications and labelling may differ.