 Various warfarin initiation regimens have been attempted, but none are in common use. In 1984, Fennerty proposed an every 16-hour dosing initiation nomogram for patients with venous thromboembolism whose average age was 52 years. This nomogram never gained wide support because of the awkward dosing interval and because it had been used in a patient population much younger than the average population of patients who take warfarin. In 1998, the modified Fennerty nomogram was introduced and dosed patients with warfarin every 24 hours. The nomogram enrolled an older population, average age of 78 years. However, 35 of these patients had excessively high INRs that exceeded 4.0 within the first 4 days of warfarin initiation. 