Patients with excessive INR values are usually treated
uniformly with regard to dosing of phytonadione. 6,14,16-19
Since patients often present with a wide range of INR val-
ues, this approach may lead to failure in response on the
one hand or to overcorrection of INR on the other. In-
deed, one recent study demonstrated that response to phy-
tonadione was dependent on INR at presentation. 21 When
patients in that study were categorized as severely overan-
ticoagulated (INR9.5), 24-hour phytonadione treat-
ment failure rate was 83%, whereas in mildly overantico-
agulated patients (INR9.5) this rate was 16%. In another
prospective study 17 patients were allocated to receive phy-
tonadione according to INR at presentation (below or above
INR of 10).