The principles of treatment and management of anticoagulant rodenticide poisoning are summarized in Table 4. Basically, once blood samples have been collected for the requisite diagnostic tests, the affected animal should receive a parenteral injection of vitamin K1. This form of the vitamin is preferred because vitamin K3 has little or no effect for the acute stages of poisoning . Also, vitamin K1 should not be given intravenously, as the manufacturer's insert clearly recognizes the hazard of anaphylaxis from intravenous use of this product. On numerous occasions, the authors have been informed of situations where anaphylaxis was associated with intravenous vitamin K1. Treatment with vitamin K1 should continue for up to 4-6 weeks unless laboratory monitoring of coagulation shows that values have returned to normal limits sooner. In cases where the toxicant is known to be warfarin rather than generically referred to as such, vitamin K1 supplementation is usually needed for up to 5-7 days. However, when identity of the toxicant is unknown, it is prudent to assume that one of the more toxic, longer-lasting products is involved.
The dosage of vitamin K1 given should generally not exceed 1 mg/lb/day, or at least should be given cautiously if higher doses are deemed necessary . Doses exceeding 2 mg/lb/day may be dangerous and have been shown recently to induce Heinz body hemolytic anemia . In our extensive experience with the monitoring and treatment of rodenticide poisoning cases, we have not had to exceed 1 mg/lb/day of vitamin K1 for successful control of bleeding . This regimen is about half the dosage recommended by Mount and Feldman [45, 46]. Regardless of the anticoagulant involved, it is important to initiate therapy promptly. When the product has not been identified, as frequently occurs, it is necessary to follow the regimen of prolonged treatment outlined in Table 4 to avoid relapse and to reduce the overall cost to the client.
For severely poisoned cases, bleeding may have caused serious anemia and therefore also necessitates one or more transfusions with fresh compatible whole blood. In addition to transfusions, where animals have bled in the pulmonary, pleural or pericardial cavities, surgical intervention may be necessary to remove blood to give space for lung or cardiac function. Once the poisoned animals are under treatment and are recovering, it is important to keep them quiet, confined and on a softened diet, for another 2-7 days (depending on the toxicant involved) to minimize hemorrhage in locations such as the central nervous system. As vitamin K1 replenishes circulating clotting factors in a time course consonant with their respective synthetic half-lives, it takes several days for severely depleted animals to resynthesize these factors and no longer be at risk for bleeding complications.