PURPOSE: To evaluate the response of 73 patients with antivitamin K (AVK) overdose to 3 different therapeutic regimens. METHODS: Seventy three patients were evaluated in 94 occasions: group A (N=32), consisted of drug withdrawal for 2 days followed by reduced dosage; group B (N=37), drug withdrawal and reassessment within 4 days; group C (N=25), oral administration of vitamin K. Therapeutic range was set between INR-values of 2 and 4. RESULTS: Reversal regimens did not result in differences among 61 patients who had initial INR <8 (chi²=2.352, p=0.671). There were more patients bellow therapeutic range in group C (N=14) than group B (N=19) (chi² =9.998, p=0.007). After intervention, 7 patients in group B still had INR >4, but 5 of them were bellow 4.5, without increased bleeding risk. There were 10 patients in group C bellow therapeutic range, 6 of them with INR < 1.6, with risk of thromboembolism. Thirteen patients bled, but none required transfusion. CONCLUSION: Reversal of excessive oral anticoagulation can be safely performed by initial withdrawal of the drug, followed by lower doses. Vitamin K administration may lead to INR bellow the therapeutic range. This should be reserved for patients with high INR or in the presence of bleeding.
oral anticoagulation; vitamin K; bleeding; throboembolism
