Rivaroxaban for Treatment in Venous or Arterial Thrombosis in Neonates

Inclusion Criteria: * Children from birth to less than 6 months with documented symptomatic or asymptomatic venous or arterial thrombosis who have been treated with anticoagulant therapy for at least 5 days. * Gestational age at birth of at least 37 weeks. * Hemoglobin, platelets, creatinine, ALT and total and direct bilirubin assessed within 10 days prior to enrollment. * Oral feeding/nasogastric/gastric feeding for at least 10 days. * Informed consent provided. * Body weight \>2600 g Exclusion Criteria: * Active bleeding or high risk for bleeding contraindicating anticoagulant therapy, including history of intra-ventricular bleeding. * Symptomatic progression of thrombosis during preceding anticoagulant treatment. * Planned invasive procedures, including lumbar puncture and removal of non-peripherally placed central lines during study treatment. * Hepatic disease which is associated with either: coagulopathy leading to a clinically relevant bleeding risk, or alanine aminotransferase (ALT) \> 5x upper level of normal (ULN) or total bilirubin (TB) \> 2x ULN with direct bilirubin \> 20% of the total. * Creatinine \>1.5 times of normal. * Uncontrolled Hypertension defined as \>95th percentile. * History of gastrointestinal disease or surgery associated with impaired absorption. * Platelet count \<100 x 109/L. * Concomitant use of strong inhibitors of both cytochrome P450 isoenzyme 3A4 (CYP3A4) and P-glycoprotein (P-gp), e.g. all human immunodeficiency virus protease inhibito…