How should I use Tysabri(Natalizumab)?

The injection is available in a specification of 300mg/15mL (20mg/mL), presenting as a colorless to slightly opalescent solution, which requires dilution before intravenous infusion. The dose is 300mg per administration, administered intravenously once every 4 weeks, with an infusion time of approximately 1 hour. Intravenous push or rapid injection is strictly prohibited.

Using aseptic technique, withdraw 15mL of the medicinal solution from a single-dose vial and inject it into 100mL of 0.9% Sodium Chloride Injection. Gently invert to mix; shaking is to be avoided. The concentration of the diluted solution is 2.6mg/mL, which must be used within 48 hours. It may be refrigerated (at 2°C–8°C) and should be warmed to room temperature before use; freezing is not allowed.

Patients must be closely monitored throughout the entire infusion process. After the first 12 infusions, observation is required for 1 hour; if no hypersensitivity reactions occur during these 12 infusions, the observation time for subsequent infusions may be shortened based on clinical judgment.

Special requirements for patients with Crohn's Disease (CD): If no therapeutic effect is achieved within 12 weeks of induction therapy, the treatment should be discontinued. If chronic oral corticosteroids cannot be discontinued within 6 months of treatment, the treatment should also be discontinued.