Generic Name

Tofacitinib

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Classification

FDA Approved Indications

• Rheumatoid arthritis (moderate to severe, in patients who have inadequate response to methotrexate or other DMARDs)
• Juvenile idiopathic arthritis (polyarticular course)
• Ulcerative colitis

Mechanism of Action

Tofacitinib inhibits Janus kinase enzymes (mainly JAK1 and JAK3), which are involved in the signaling of cytokine receptors that regulate immune cell function, thereby modulating the immune response and reducing inflammation.

Dosage and Administration

Adult: 20 mg once daily for rheumatoid arthritis or ulcerative colitis (dose may be adjusted based on response and tolerability); for rheumatoid arthritis, the recommended dose is 5 mg twice daily or 11 mg once daily in ulcerative colitis.

Pediatric: Not approved for pediatric use.

Geriatric: No specific dose adjustment, but caution advised due to increased risk of infections.

Renal Impairment: No specific adjustment required for mild to moderate impairment; data limited for severe impairment.

Hepatic Impairment: Use with caution; contraindicated in severe hepatic impairment.

Pharmacokinetics

Absorption: Rapid absorption, approximately 4 hours to peak plasma concentration.

Distribution: Protein binding approximately 50%.

Metabolism: Mainly metabolized via CYP3A4 and to a lesser extent by CYP2C19.

Excretion: Excreted primarily in feces (about 70%) and urine (around 15%).

Half Life: Approximately 3 hours.

Contraindications

• Active or latent tuberculosis or other serious infections.
• History of hypersensitivity to tofacitinib.

Precautions

• Increase risk of infections, make sure to screen for infections before initiation.
• Monitor for signs of infection during therapy.
• Use with caution in patients with liver disease, cytopenias, or a history of malignancy.

Adverse Reactions - Common

• Upper respiratory tract infections (Frequent)
• Headache (Common)
• Diarrhea (Common)
• Elevated liver enzymes (Common)

Adverse Reactions - Serious

• Serious infections (e.g., pneumonia, herpes zoster) (Less common)
• Gastrointestinal perforation (Rare)
• Blood clots (deep vein thrombosis and pulmonary embolism) (Rare)
• Malignancies (lymphoma, other cancers) (Rare)

Drug-Drug Interactions

• Inhibitors or inducers of CYP3A4 (e.g., ketoconazole, rifampin)
• Other immunosuppressants (e.g., azathioprine, cyclosporine)

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Patient/Family Teaching

• Report any signs of infection immediately.
• Do not receive live vaccines while on therapy.
• Avoid catching and spreading infections.
• Follow up with lab tests as recommended.

Special Considerations

Black Box Warnings:

• serious infections, including tuberculosis, lymphoma, and other malignancies, and thrombosis.

Genetic Factors: Limited data available.

Lab Test Interference: May cause changes in lipid profiles, liver enzymes, and blood counts.

Overdose Management

Signs/Symptoms: Increased risk of infections, hematologic abnormalities.

Treatment: Supportive care; no specific antidote.

Storage and Handling

Storage: Store at room temperature between 20°C to 25°C (68°F to 77°F).

Stability: Stable until the expiration date on the packaging.