DOXORUBICIN REVERSIBLY DECREASES THE ANTITHROMBOGENICITY OF HEPARIN IMMOBILIZED ON CENTRAL VENOUS CATHETERS

This is an in vitro study of the effects of doxorubicin on heparin imm obilized on polyvinyl chloride (PVC) tubing. Doxorubicin contains an a mino group that binds up to 16 heparin molecules, farming insoluble co mplexes if they are added to the same infusion. Three systems were tes ted: doxorubicin in perfusing blood, cerebrospinal fluid, and 0.9% sod ium chloride (NaCl). The antithrombogenicity of immobilized heparin is impaired on exposure to doxorubicin. However, the reaction is reversi ble provided the PVC tubing system is thoroughly washed. Heparinized t ubing perfused for 12 hours in blood with doxorubicin (0.027 mg/mL) de creased the activity of the immobilized heparin to 6.0% compared with 43% of that exposed to blood only. Exposure to doxorubicin (0.27 mg/mL ) for 15 minutes in NaCl decreased the activity to 3% compared with th at of NaCl only. Continuous washing for 10 minutes (8 mL/min) resulted in regained activity. This indicated a reversible reaction between im mobilized heparin and doxorubicin. Cyclophosphamide, netilmicin, and g entamicin did not affect the antithrombogenicity of heparin in any sol ution.