ORAL ANTICOAGULATION IN PEDIATRIC-PATIENTS - DOSE REQUIREMENTS AND COMPLICATIONS

The lack of oral anticoagulant guidelines specific to paediatric pract ice has led to the adoption of adult regimens, often without scientifi c evidence of efficacy or safety. A two year prospective study of anti coagulant control was carried out in 45 children aged 9 months to 18 y ears, the majority of whom were receiving primary prophylactic anticoa gulation. The main indication was congenital heart disease, either wit h (n=8) or without (n=34) mechanical valve prosthesis. During a follow up period of 602 patient months the average interval between visits w as three weeks. Target international normalised ratios (INRs) were ach ieved on 62% and 39% of visits for children with low target INR (2.0-3 .0) and high target INR (3.0-4.0) respectively. However warfarin dose was altered on only 22% of visits. Warfarin doses required to achieve a stable INR of 2.0-3.0 in 33 children were strongly correlated with w eight [dose (mg/d)=0.07 X weight (kg)+0.54] but independently influenc ed by age. No thrombotic complications were recorded, and haemorrhagic events were infrequent (2.1% of visits) and, with one exception, mino r. Safe outpatient oral anticoagulation is feasible in children, whose warfarin requirements appear moderately predictable and whose control is no more erratic than that of adults.