THE EFFECTS OF CAFFEINE ON FREE FATTY ACIDS AND BLOOD COAGULATION PARAMETERS OF DOGS

¹ Division of Cardiology, Philadelphia General Hospital, Philadelphia, Pennsylvania

Serial blood samples over a 4-hr period were drawn from 11 control dogs and 22 dogs who had received 25 mg/kg of caffeine sodium benzoate i.v. These samples were analyzed for various parameters of clotting and free fatty acids. No significant differences between the caffeine-treated animals and the controls were noted in the tests for clotting time in glass and silicone-treated tubes, Stypven and partial thromboplastin time. Significant changes in the serum free fatty acid levels, however, were noted as early as 70 to 90 min after the injection of caffeine. The elevations became more marked 1 hr later and were even greater at the end of 4 hr. During the interval of 2 to 4 hr after the administration of caffeine, significant shortening of the in vitro heparin tolerance time, recalcification time of the plasma and the one-stage prothrombin time were observed. Only the heparin tolerance time was shortened during the 70-to 90-min interval. The increase in free fatty acids was possibly the cause of the altered coagulation profile found in the caffeine-treated animals.