Rheumatoid arthritis、 Ankylosing Spondylitis<20230504>
#仿單變更2021
#仿單變更2023

Tofacitinib is a Janus kinase (JAK) inhibitor. Janus kinases (JAK) are intracellular enzymes and modulates a signaling pathway that influences the cellular processes of hematopoiesis and immune cell function. Signals in this pathway arise from cytokine or growth factor-receptor interactions on the cellular membrane. Inhibition of JAK prevents the phosphorylation and activation of Signal Transducers and Activators of Transcription (STATs), which modulate gene expression and other intracellular activity.

XELJANZ(5 mg/10 mg)
Absorption: 74%, Cmax: ~42.7ng/mL, Tmax: ~1hr <20210316>
Protein binding: ~40% (predominantly to albumin)
Metabolism: hepatic(70%) CYP3A4 and CYP2C19 to inactive metabolites
Excretion: primarily urine(30%) as unchanged drug; Elimination Half-life: ~3 hours
XELJANZ XR(11 mg)
1.Peak blood concentration: within 4 hours.
2.Half-life is approximately 6-8 hours.
<20240419>

Hypersensitivity to tofacitinib or any component of the formulation.

C

Excretion in breast milk unknown/not recommended

Infection (20% to 22%), Diarrhea (4%), Headache (4%), Hypertension (2%).
Warnings:
1. Infections: May increase risk for serious infections, which may result in hospitalization and/or fatality; Often developed in patients receiving concomitant immunosuppressive agents.
2. Tuberculosis: TB(pulmonary or extrapulmonary) has been reported.
3. Thrombosis (including deep venous thrombosis, pulmonary embolism, and arterial thrombosis) have been observed at an increased incidence in RA patients treated with tofacitinib and other Janus kinase inhibitors <20210316>
4. Malignancy: Lymphoma and other malignancies have been reported in patients receiving tofacitinib.

Rheumatoid arthritis and ankylosing Spondylitis <20230504> (monotherapy or in combination with methotrexate or nonbiologic disease-modifying antirheumatic drugs (DMARDs): Oral: 5 mg twice daily.
To Xeljanz XR(extended-released): Xeljanz 5mg twice daily may switch to Xeljanz XR 11mg once daily, on second day after final dose of Xeljanz.<20210316>

Moderate-to-severe impairment: Reduce dose to 5 mg once daily. Note:Tofacitinib has not been studied in patients with baseline CrCl <40 mL/minute.