| Heparin is a complex glycosaminoglycan that is widely used for its anticoagulant properties. Heparin has also been used for its antithrombotic, anti-inflammatory, and antifibrotic effects. In veterinary medicine, the use of heparin has been limited to the management of hypercoagulable disease states. It is traditionally administered either intravenously or subcutaneously. The purpose of this study was to evaluate the anticoagulant effects of heparin administered via an inhaled route in the dog. Bronchoalveolar lavage fluid was collected from healthy dogs to generate a calibration curve to relate heparin concentration (IU/mL) to clotting time in the activated partial thromboplastin time (aPTT). Healthy dogs were then administered inhaled heparin to determine the threshold dose of heparin that would prolong systemic aPTT. Inhaled total heparin doses as high as 200,000 IU failed to cause prolongation of systemic aPTT in any dog. A heparin dose of 200,000 IU of heparin was then administered and the anticoagulant activity of inhaled heparin within BALf was evaluated. No detectable activity was found in any dog. |
