Table 4.

JAK enzyme inhibitors in oral lichen planus.

Drug	Mechanism of Action	Indications	Method and Dose	Side Effect
Baricitinib	Inhibits JAK1/JAK2, blocks γc-chain, β-co-chain (IL-5, IL-130 and GM-CSF), gp6 (IL-12 family), interferon and interleukin (IL-23, IL-27, IL-19) signaling; inhibits allogeneic T cell responses to keratinocytes in vitro	Patients not responding to conventional treatment	Whole body: 3.4mg, ×2/d	Slight increase in cholesterol
Tofacitinib	Inhibition of JAK1/JAK2/JAK3 STAT1/STAT3/STAT5, competitively binds to the active region of adenosine triphosphate kinase and blocks activation of signal transduction	Application to patients with lichen planus of the scalp	Topical: 5mg in LP 2%, ×2/d Whole body: 10-15mg/d	Temporary abnormal hemoglobin and creatinine, mildly elevated triglyceride and cholesterol levels
Upadacitinib	Inhibition of JAK1 enzyme activity	Patients with erosive oral lichen planus	Whole body: 15mg daily	No significant adverse reactions
Peficitinib	Inhibition of JAK3 enzyme activity and JAK1/3-mediated cell proliferation	Applied to generalized lichen planus	Systemic dosing, exact dosage not yet known	No significant adverse reactions
Abrocitinib	Inhibition of JAK1 enzyme activity	Applied to generalized lichen planus	Whole body: 100mg/200mg daily	respiratory and/or gastrointestinal level