DDAVP (desmopressin; 1‐deamino‐cys‐8‐d‐arginine‐vasopressin) treatment in children with haemophilia B

We tested the response to desmopressin (1‐deamino‐cys‐8‐d‐arginine‐vasopressin; DDAVP) in four patients with haemophilia B [factor IX (F IX) at diagnosis 1·4–5%]. The activated partial thromboplastin time (aPTT) was significantly shortened in all patients. Although there was an up to 1·4‐fold increase in F IX levels in three patients, maximal F IX activity remained below 10%. Much more prominent were the increases in F VIII (three‐ to fourfold), in von Willebrand factor antigen (VWF:Ag; 2·5‐fold) and particularly in VWF collagen‐binding activity (VWF:CBA; fivefold). These changes were reflected by the prophylactic efficacy of DDAVP for dental surgery. After pretesting, DDAVP could be a useful drug for reducing the need for plasma products for prevention of minor surgical bleeding in patients with mild to moderate haemophilia B.