May increase the risk for bone marrow reticulin formation or progression; collagen fibrosis (not associated with cytopenias) was observed in clinical trials (treatment should be discontinued with onset of new or worsening cellular morphologic abnormalities or cytopenias). Cataract formation or worsening may occur. May cause hepatotoxicity (treatment should be discontinued for ALT levels ≥3 times ULN and which are progressive, or persistent ≥4 weeks, or accompanied by increased direct bilirubin, or by clinical signs of liver injury or evidence of hepatic decompensation. Hepatotoxicity usually recurred with retreatment after therapy interruption). Stimulation of cell surface TPO receptors may increase risk for hematologic malignancies. Upon discontinuation of therapy, thrombocytopenia may worsen, increasing risk of bleeding, particularly in patients receiving anticoagulants or antiplatelet agents. Thromboembolism may occur with excess increases in platelet levels. This product is available only through a restricted distribution program. Should be discontinued if platelet count does not increase after 4 weeks at the maximum dose (75 mg).