Eighty-four outpatients with nonrheumatic atrial fibrillation starting oral anticoagulant treatment were adminis tered warfarin (10 mg/day) for the first 2 days of treatment. Prothrombin time, expressed as International Normalized Ratio (INR), was measured on day 3 and plotted against the weekly warfarin maintenance dose, defined as the dose able to maintain INR between 2.0 and 3.0 (therapeutic range) on three consecu tive occasions, 1 week apart. The data fit a regression line (r = 0.74, p < .0001) that we use to estimate the weekly maintenance dose of other patients.
Dalen JE, Hirsh J, eds. Third ACCP Consensus Conference on Antithrombotic Therapy. Chest 1992;102:303S.
2.
Petersen P., Boysen G., Godtfredsen J., Andersen ED, Andersen B.Placebo-controlled, randomized trial of warfarin and aspirin for prevention of thromboembolic complications in chronic atrial fibrillation. The Copenhagen AFASAK study. Lancet1989;1:175.
3.
Stroke Prevention in Atrial Fibrillation Study Group Investigators.Stroke prevention in atrial fibrillation study. Final results. Circulation1991;84:527.
4.
TheBoston Area Anticoagulation Trial for Atrial Fibrillation Investigators. The effect of low-dose warfarin on the risk of stroke in patients with nonrheumatic atrial fibrillation. N Engl J Med1990; 323:1505.
5.
Connolly SJLaupacis A., Gent M., et al. Canadian atrial fibrillation study. J Am Coll Cardiol1991 ;8:49.
6.
Ezekowitz MD , Bridgers SL, James KE, et al. Warfarin in the prevention of stroke associated with nonrheumatic atrial fibrillation. Veterans Affairs Stroke Prevention in Nonrheumatic Atrial Fibrillation Investigators . N Engl J Med1992;327:1406.
7.
Kulbertus HE, Leval-Rutten FD, Bartsch P., et al. Atrial fibrillation in the elderly ambulatory patients. In: Kulbertus HE, Olsson SB, Schlepper M, eds., Atrial fibrillation Molndal, AB Hassle, Kiruna, Sweden 1992:148.
8.
Lake FR, McCall MG, Cullen KJ, et al. Atrial fibrillation and mortality in an elderly population. Austr N ZJ Med1989;19:321.
9.
Hirsh J., Dalen JE, Deykin D., et al. Oral anticoagulants. Mechanism of action, clinical effectiveness and optimal therapeutic range. Chest1995;108:231S.
10.
British Society of Haematology, British Committee for Standards in Haematology, Haemostasis and Thrombosis Task Force.Guidelines on oral anticoagulation: second edition. J Clin Pathol1990; 43:177.
11.
Holford Nhg.Clinical pharmacokinetics and pharmacodynamics of warfarin: understanding the dose-effect relationship. Clin Pharmacokin1986; 11:483.
12.
Fennerty A. , Dolben J., Thomas P., et al. Flexible induction dose regimen for warfarin and prediction of maintenance dose. BMJ1984;288:1268.
13.
Shetty Hgm, Fennerty AG, Routledge PAClinical pharmacokinetic considerations in the control of oral anticoagulant therapy. Clin Pharmacokin1989;16:238.
14.
Flegel KM, Hanley J.Risk factors for stroke and other embolic events in patients with nonrheumatic atrial fibrillation. Stroke1989 ;20:1000.
15.
Wolf PA, Abbott RD, Kannel WBAtrial fibrillation as an independent risk factor for stroke: the Framingham study. Stroke1991; 22:983.
16.
Wolf PA, Abbott RD, Kannel WB: Atrial fibrillation: a major contributor to stroke in the elderly: the Framingham Study. Arch Intern Med1987 ;147:1561.
17.
Kannel WB, Abbott RD, Savage DD, et al. Epidemiologic features of chronic atrial fibrillation: the Framingham Study. N Engl J Med1982;306:1019.
18.
James AH, Britt RP, Raskino CL, et al. Factors affecting the maintenance dose of warfarin. J Clin Pathol1992;45:704.
19.
Redwood M., Taylor C., Bain BJ, et al. The association of age with dosage requirement for warfarin . Age Aging1991;20:217.
20.
Doi Sar.Pharmacodynamic optimization of warfarin therapy. Clin Pharmacol Ther1994;55:597.