Before taking Tysabri(Natalizumab)

Progressive Multifocal Leukoencephalopathy (PML)

Risk factors include positive anti-JCV antibodies, long treatment duration (especially > 2 years), and previous use of immunosuppressants. Anti-JCV antibody testing should be performed before initiating medication and regular rechecks should be conducted.

If any neurological symptoms occur (e.g., limb weakness, visual impairment, cognitive changes), medication should be discontinued immediately and an assessment should be carried out. Monitoring should be continued for at least 6 months after drug discontinuation.

TYSABRITOUCH® Prescribing Program

Due to the risk of PML, this product can only be obtained through the TOUCH® Program. Physicians, patients, pharmacies, and infusion centers must all register and comply with monitoring requirements.

Herpes Infections

It can cause herpetic encephalitis, meningitis, and acute retinal necrosis (ARN), which may lead to blindness or death. If relevant symptoms appear, medication should be discontinued immediately and antiviral treatment should be administered.

Hepatotoxicity

Acute liver failure requiring liver transplantation has been reported. If jaundice occurs or liver injury indicators rise, medication should be discontinued.

Hypersensitivity Reactions and Antibody Formation

Allergic reactions may occur, most frequently within 2 hours of infusion. If a hypersensitivity reaction occurs, permanent discontinuation of the medication is required. Antibody testing can guide treatment decisions.

Immunosuppression and Infections

It may increase the risk of infections, including opportunistic infections. Concurrent use with immunosuppressants should be avoided.

Abnormal Laboratory Findings

Reversible elevations in lymphocytes, monocytes, and eosinophils, as well as a mild decrease in hemoglobin, may occur.

Hematological Abnormalities

It may cause thrombocytopenia, including immune thrombocytopenic purpura (ITP). Neonates may develop thrombocytopenia and anemia, and blood routine tests should be performed after birth.

Immunization

There is no data supporting the safety of live vaccines, so vaccination with live vaccines should be avoided.