Patients were hospitalized for 72 hours and were randomly assigned
(sealed envelopes) by a physician not involved in the
study to receive either oral or intravenous phytonadione. Doses
of phytonadione were determined according to baseline INR
at presentation: patients with INR values of 6 to 10 received
either an intravenous dose of 0.5 mg or an oral dose of 2.5 mg.
Patients with INR values greater than 10 received either an intravenous
dose of 1.0 mg or an oral dose of 5.0 mg.
Intravenous phytonadione (Konakion, 10-mg ampoules;
Roche, Basel, Switzerland) was serially diluted and a volume
containing 0.5 or 1.0 mg was prepared in a 150-mL saline infusion
bag and infused over 30 minutes. Blood pressure and
pulse were determined before and after infusion. Oral phytonadione
(2.5 or 5.0 mg) was administered as a single phytonadione
tablet (Mephyton, 5.0 mg; Merck & Co, West Point,
Pa). Any adverse event during phytonadione administration was
recorded.
In all patients warfarin was withheld for 24 hours following
phytonadione administration and resumed thereafter in all
patients defined as responders.