|
| |
|
Desmopressin is a synthetic analogue of arginine vasopressin (antidiuretic hormone), 1-deamino-8-arginine vasopressin (DDAVP). It is a useful drug for dogs with von Willebrand disease. Desmopressin elevates plasma vWf:Ag by inducing the release of vWf from stores (Weibel-Palade bodies) in endothelial cells. Factor VIII activity may also increase secondarily to the increased vWf. DDAVP will only work in animals with endothelial stores of vWf, ie. dogs with type I vWD, e.g. Dobermans, and is ineffective in dogs with type III vWD, e.g. Scottish terriers, which lack vWf stores. Repeat injections produce a diminishing response, due to depletion of stores, therefore the drug has limited use in the treatment of hemorrhagic episodes of vWD (although it can be used as an adjunct to plasma products). It is also quite expensive, which limits its use. Desmopressin is recommended as presurgical prophylaxis in Dobermans "at risk" of hemorrhage (i.e. those with vWf:Ag values < 35% or those that have shown previous bleeding tendencies), and in Dobermans of unknown vWD status with a prolonged BMBT. It is available as a liquid intranasal preparation for treatment of diabetes insipidus in human beings . The latter preparation is injected subcutaneously 30 minutes prior to surgery, at a dose of 1 µg/kg diluted to a "workable" volume (eg. 1 ml) with sterile saline. This dose may shorten the BMBT in vWD Dobermans for up to 4 hours. However, response to the drug is unpredictable in dogs with vWD (some dogs may not respond at all) and DDAVP should not be relied upon to achieve surgical hemostasis. Plasma or cyroprecipitate should be available in the event of excessive surgical hemorrhage. DDAVP is also used by some people to boost values of vWf:Ag in donor dogs for transfusion purposes.
|
