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9780521704632c23 CUFX213A/Peck 9780521618168 December 29, 2007 14:58
23 Drugs affecting coagulationMiscellaneous
Dextran 40 and dextran 70
These are polysaccharides that contain chains of glucose. They are produced by the
fermentation of sucrose by the bacteriumLeuconostoc mesenteroides.Uses
They are used as prophylaxis against peri-operative venous thrombosis and as
plasma volume expanders.Mechanism of action
Their anticoagulant activity appears to depend on reducing platelet adhesiveness
and a specific inhibitory effect on the von Willebrand factor. They also reduce red cell
aggregation and provide a protective coat over vascular endothelium and erythro-
cytes. The dilution of clotting factors and volume expansion also improves micro-
circulatory flow.Other effects
These include fluid overload, allergic reactions and anaphylaxis. Dextran 70 can
impair cross matching by rouleaux formation. Renal failure is a rare complication.Epoprostenol (prostacyclin – PGI 2 )
This is a naturally occurring prostaglandin.Uses
Epoprostenol is used to facilitate haemofiltration by continuous infusion into the
extracorporeal circuit.Mechanism of action
Epoprostenol causes inhibition of platelet adhesion and aggregation by stimulating
adenylate cyclase. The ensuing rise in cAMP reduces intracellular Ca^2 +,effecting the
change. It may also have a fibrinolytic effect. The recommended dose range is 2–12
ng.kg−^1 .min−^1.Side effects
These relate to its vasodilator properties (hypotension, tachycardia, facial flushing
and headache).