Tysabri (Natalizumab) - Drug Interactions, Contraindications, Overdosage, etc

DRUG INTERACTIONS

Because of the potential for increased risk of PML and other infections, Crohn's disease patients receiving TYSABRI should not be treated with concomitant immunosuppressants (e.g., 6-mercaptopurine, azathioprine, cyclosporine, or methotrexate) or inhibitors of TNF-α, and corticosteroids should be tapered in those patients with Crohn's disease who are on chronic corticosteroids when they start TYSABRI therapy [see Boxed Warning, Indications and Usage (1.2), Warnings and Precautions (5.1, 5.4) ]. Ordinarily, MS patients receiving chronic immunosuppressant or immunomodulatory therapy should not be treated with TYSABRI [see Boxed Warning, Indications and Usage (1.1), Warnings and Precautions (5.1, 5.4) ].

OVERDOSAGE

Safety of doses higher than 300 mg has not been adequately evaluated. The maximum amount of TYSABRI that can be safely administered has not been determined.

CONTRAINDICATIONS

• TYSABRI is contraindicated in patients who have or have had progressive multifocal leukoencephalopathy (PML) [see Boxed Warning, Warnings and Precautions (5.1) ].
• TYSABRI should not be administered to a patient who has had a hypersensitivity reaction to TYSABRI. Observed reactions range from urticaria to anaphylaxis [see Warnings and Precautions (5.3) ].

REFERENCES

• Best WR, Becktel JM, Singleton JW, Kern F: Development of a Crohn's Disease Activity Index, National Cooperative Crohn's Disease Study. Gastroenterology 1976; 70(3): 439-444.