Antidotal effect of vitamin K1 against warfarin-induced anticoagulation in horses.

The study investigates the effectiveness of vitamin K1 in reversing the anticoagulation induced by warfarin in horses. The research found that vitamin K1 significantly shortened the coagulation time induced by warfarin.

Research Process

• The study was conducted on four mature horses. The horses were given warfarin intravenously until their prothrombin (PT) time was approximately 1.5 times longer than their normal time. PT time refers to the time it takes for blood to clot.
• Five separate experiments were conducted as part of this research. In Experiment 1, researchers evaluated the time it took for PT to return to its base-line value after discontinuing warfarin.
• In Experiment 2, horses were administered two doses of vitamin K1, six hours apart, and their PT was monitored for 24 hours.
• In Experiments 3 and 4, horses were dosed with warfarin as in Experiment 1 and then treated with 300 mg and 500 mg doses of vitamin K1 respectively. The PT reversal times were assessed.
• In the final experiment, one horse was removed from the study, one was given 300 mg of vitamin K1 via intravenous (IV), and two were given 300 mg of vitamin K1 via subcutaneous injection (SC), with their reversal times evaluated.

Results

• It was found that the therapeutic response time after stopping warfarin was 30 hours, and the PT reversal time was about 5 days from the last warfarin dose.
• However, introducing 100 mg dose of Vitamin K1 significantly reduced the therapeutic response time to 12 hours, and the PT reversal time to 24 hours.

Conclusion

• The study concluded that Vitamin K1 is effective in reversing warfarin-induced anticoagulation in horses, shortening the time it takes for blood to clot back to normal levels.