Optimal loading dose for the initiation of warfarin: a systematic review

Table 2 Dosing regimes

Study	Dosing Protocol on Days 1&2 (Reference for nomogram used)
Harrison 1997 ^ξ	5 mgs on day 1, up-to 5 mgs on day 2 vs. 10 mgs on day 1, up-to 10 mgs on day 2
Crowther 1999 ^ξ	5 mgs on day 1, up-to 5 mgs on day 2 vs. 10 mgs on day 1, up-to 10 mgs on day 2
Kovacs 2003	5 mgs vs. 10 mgs on days 1&2 ^δ
Quiroz 2006	5 mgs vs. 10 mgs on days 1&2
5 mg trials
Ageno 2001	5 mg Day 0 (subsequent doses adjusted) vs. 2.5 mg on days 0 through 4 (dose modified if <1.5 or >3.0 on day 3)
Shine 2003	5 mg on day 1, up-to 5 mgs on day 2 vs. Calculated dose on day 1, up-to 100% calculated dose on day 2
Age trials
Roberts 1999	Age adjusted nomogram (6-10 mg) on day 1, 0.5-10 mg on day 2 vs. Fennerty protocol (10 mg on day 1, 0.5 mg-10 mg on day 2) ^ψ
Gedge 2000	Age stratified 65-75 years & 75 yrs - 10 mg on day 1, upto 5 mg on day 2 vs. Modified Fennerty protocol, 10 mg day 1 and up to 10 mgs on day 2
Genotyping trials
Hillman 2005	5 mg on days 1 & 2 vs. Model - genetic nomogram
Anderson 2007	10 mg on days 1 & 2 vs. Model - 2× predicted maintenance dose on days 1 & 2 followed by predicted dose
Caraco 2008	5 mg on day 1 & up to 5 mg on day 2 vs. Model - genetic nomogram

^ξ Crowther 1997 report: Crowther MA, Harrison L, Hirsh J. Reply: Warfarin: Less May Be Better. Ann Intern Med 1997 August 15;127(4):333.
^δKovacs MJ, Anderson DA, Wells PS. Prospective assessment of a nomogram for the initiation of oral anticoagulation therapy for outpatient treatment of venous thromboembolism. Pathophysiol Haemost thromb 2002;321:131-133
^ψ Fennerty A, Dolben J, Thomas P et al. Flexible induction dose regimen for warfarin and prediction of maintenance dose. British Medical Journal Clinical Research Ed 1984 April 28;288(6426):1268-70.

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