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Table 1 Warfarin dosing relative to initiation and discontinuation of boceprevir

From: Warfarin and boceprevir interaction causing subtherapeutic international normalized ratio: a case report

Date Weekly ribavirin dose (mg) Weekly warfarin dose (mg) POC-INR, LAB-INR* Important notes
11/07/2012   15 1.9  
01/08/2012 1200 15 2.8 PEG-INF and RBV started
15/08/2012 1200 15 1.9  
30/08/2012 1200 15 2.5  
31/08/2012 1200 ----- ----- Boceprevir started
05/09/2012 1200 15 2.5  
19/09/2012 1000 15 1.2  
25/09/2012 1000 17.5 1.2 Consumed high vitamin K food on 24/09/12
01/10/2012 600 17.5 1.3 Epoetin alfa and vitamin B12 added
10/10/2012 600 20 1.3  
16/10/2012 200 23.75 1.48*  
24/10/2012 200 26.25 2.2  
31/10/2012 200 26.25 1.72*  
07/11/2012 200 27.5 2.0  
14/11/2012 200 26.25 1.8 1.82* Patient took less warfarin than instructed.
27/11/2012 400 27.5 2.24*  
12/12/2012 600 27.5 2.0 2.02*  
26/12/2012 800 28.75 2.1  
16/01/2013 800 28.75 1.7  
30/01/2013 800 31.25 2.0 Consumed high vitamin K food twice in past week
13/02/2013 600 31.25 3.3  
27/02/2013 200 30 2.4 Iron added
13/03/2013 400 30 2.9 Recent suprapubic abscess; completing amoxicillin/clavulanate, which started 07/03/13
27/03/2013 200 30 2.2  
10/04/2013 200 30 2.4  
24/04/2013 400 30 3.6 New facial abscess, starting 10-day course clindamycin
08/05/2013 400 28.75 2.5 HCV medications DISCONTINUED due to low platelets
16/05/2013   23.75 1.48*  
29/05/2013   26.25 2.8  
12/06/2013   Unknown 2.2 Hospitalized at outside hospital for UTI and bacteremia from 04/06/–07/06/13, ciprofloxacin added
19/06/2013   25 3.1  
26/06/2013   25 3.7  
10/07/2013   25 3.2 Patient took more warfarin than instructed
24/07/2013   23.25 2.4  
15/08/2013   23.75 2.4  
10/09/2013   23.75 3.0  
10/10/2013   23.75 2.5  
06/11/2013   23.75 3.2  
  1. Abbreviations: HCV hepatitis C virus, INR international normalized ratio, LAB laboratory, PEG-INF peginterferon alfa-2a, POC point-of-care, RBV ribavirin, UTI urinary tract infection. *Laboratory INR.