Anaphylaxis and Other Allergic Reactions. Anaphylaxis has been reported as a rare complication of interferon beta-1b use. Other allergic reactions have included dyspnea, bronchospasm, tongue edema, skin rash and urticaria. Discontinue EXTAVIA if anaphylaxis occurs. The removable rubber cap of the diluent pre-filled syringe contains natural rubber latex and should not be handled by latex-sensitive individuals as it may cause allergic reactions.
Depression and Suicide. Depression and suicide have been reported to occur with increased frequency in patients receiving interferon compounds, including interferon beta-1b. Patients treated with EXTAVIA should be advised to report immediately any symptoms of depression and/or suicidal ideation. Consider discontinuation of EXTAVIA if depression occurs.
Congestive Heart Failure. Monitor patients with pre-existing congestive heart failure (CHF) for worsening of their cardiac condition during initiation of and continued treatment with EXTAVIA. Consider discontinuation of EXTAVIA if worsening of CHF occurs with no other etiology.
Injection Site Reactions Including Necrosis. Injection site reactions, including injection site necrosis, can occur with the use of interferon beta products, including EXTAVIA. Injection site reactions occurred in 78% of patients receiving interferon beta-1b (compared to 26% on placebo) in controlled clinical trials with injection site necrosis reported in 4% of interferon beta-1b patients (compared to 0% on placebo). Injection site abscesses and cellulitis have been reported in the postmarketing setting with use of interferon beta products including EXTAVIA. Some cases required treatment with hospitalization for surgical drainage and intravenous antibiotics. Periodically evaluate patient understanding and use of aseptic self-injection techniques and procedures, particularly if injection site necrosis has occurred. Patients should be advised of the importance of rotating injection sites with each dose. Whether to discontinue therapy following a single site of necrosis is dependent on the extent of necrosis. For patients who continue therapy with EXTAVIA after injection site necrosis has occurred, avoid administration of EXTAVIA into the affected area until it is fully healed. If multiple lesions occur, change injection site or discontinue therapy until healing occurs.
Leukopenia. Leukopenia was reported in 18% of patients receiving interferon beta-1b (compared to 6% on placebo) in controlled clinical trials leading to a reduction in dose in some patients. Monitoring of complete blood and differential white blood cell counts is recommended. Patients with myelosuppression may require more intensive monitoring of complete blood cell counts, with differential and platelet counts.
Thrombotic Microangiopathy. Cases of thrombotic microangiopathy (TMA), including thrombotic thrombocytopenic purpura and hemolytic uremic syndrome, some fatal, have been reported with interferon beta products, including EXTAVIA. Cases have been reported several weeks to years after starting interferon beta products. Discontinue EXTAVIA if clinical symptoms and laboratory findings consistent with TMA occur, and manage as clinically indicated.
Flu-Like Symptom Complex. The rate of flu-like symptom complex for patients on interferon beta-1b was 57% (vs 37% on placebo) in controlled clinical trials. Analgesics and/or antipyretics on treatment days may help ameliorate flu-like symptoms associated with EXTAVIA use.
Seizures. Seizures have been temporally associated with the use of beta interferons in clinical trials and postmarketing safety surveillance.
Drug-induced Lupus Erythematosus. Cases of drug-induced lupus erythematosus have been reported with some interferon beta products, including EXTAVIA. Signs and symptoms of drug-induced lupus reported in patients treated with EXTAVIA have included rash, serositis, polyarthritis, nephritis, and Raynaud’s phenomenon. EXTAVIA therapy should be stopped if patients develop new signs and symptoms of this syndrome.
Monitoring for Laboratory Abnormalities. In addition to those laboratory tests normally required for monitoring patients with multiple sclerosis, complete blood and differential white blood cell counts, platelet counts and blood chemistries including liver function tests are recommended at one, three, and six months after introduction of EXTAVIA therapy, and periodically thereafter in the absence of clinical symptoms.
Pregnancy. Patients should be warned of the potential hazard to the fetus. EXTAVIA should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
Most Common Adverse Reactions. The most commonly reported adverse reactions (at least 5% more frequent on interferon beta-1b than on placebo) in controlled clinical trials were injection site reaction (78% vs 26% for placebo), lymphopenia (86% vs 66%), flu-like symptoms (57% vs 37%), myalgia (23% vs 14%), leukopenia (13% vs 4%), neutropenia (13% vs 5%), increased liver enzymes (SGPT to greater than five times baseline value [12% vs 4%], SGOT to greater than five times baseline value [4% vs 1%]), headache (50% vs 43%), hypertonia (40% vs 33%), pain (42% vs 35%), rash (21% vs 15%), insomnia (21% vs 16%), abdominal pain (16% vs 11%), and asthenia (53% vs 48%).
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