Hemolytic anemia is primary toxicity of oral therapy, usually occurring within 1-2 weeks of therapy initiation. Anemia associated with ribavirin may worsen underlying cardiac disease. Avoid use in significant/unstable cardiac disease. Ribavirin monotherapy not effective for chronic hepatitis C infection. Use with caution in renal impairment (avoid use in CrCl <50 mL/minute). Autoimmune/infectious disorders occurred with combination therapy (use with caution in autoimmune disease or severe infection). Bone marrow suppression occurred with combination therapy (discontinue if this occurs). Dental and periodontal disorders reported with combination therapy. Xerostomia may contribute to and/or exacerbate dental disorders. Severe cutaneous reactions, including Stevens-Johnson syndrome and exfoliative dermatitis reported (rarely) with combination therapy. Discontinue with signs or symptoms of severe skin reactions. Diabetes occurred with combination therapy. Acute hypersensitivity reactions (e.g. anaphylaxis, angioedema, bronchoconstriction, and urticaria) observed (rarely) with combination therapy. Pancreatitis occurred with combination therapy. Discontinue therapy in suspected/confirmed pancreatitis. Severe psychiatric events occurred including depression and suicidal behavior during combination therapy. Avoid use in psychiatric history (discontinue if severe psychiatric symptoms occur). Pulmonary symptoms associated with combination therapy; use with caution in pulmonary disease, including sarcoidosis. Use with caution in patients requiring assisted ventilation as precipitation of drug in respiratory equipment may interfere with safe and effective patient ventilation. Ribavirin is potentially mutagenic, tumor-promoting, and gonadotoxic.