scholarly journals Decreased warfarin sensitivity among patients treated with elbasvir and grazoprevir for hepatitis C infection

2019 ◽  
Vol 76 (17) ◽  
pp. 1273-1280
Author(s):  
Douglas D DeCarolis ◽  
Yi-Chieh Chen ◽  
Anders D Westanmo ◽  
Christopher Conley ◽  
Amy A Gravely ◽  
...  
Keyword(s):  
Hepatitis C ◽  
Therapeutic Range ◽  
Antiviral Agents ◽  
Warfarin Dose ◽  
International Normalized Ratio ◽  
Sensitivity Index ◽  
Veterans Health ◽  
Health Administration ◽  
Hepatitis C Infection ◽  
The Mean

Abstract Purpose We previously reported an interaction with warfarin anticoagulation when initiating treatment with direct-acting antiviral agents for hepatitis C infection. A decreased warfarin sensitivity led to subtherapeutic anticoagulation. To study this interaction further, we expanded our research to include patients treated with the combination of elbasvir and grazoprevir concurrent with warfarin anticoagulation and investigated changes in warfarin sensitivity during and after treatment. Methods Using electronic health records of the Veterans Health Administration, patients starting treatment with elbasvir–grazoprevir for hepatitis C infection concurrent with warfarin anticoagulation were identified. Inclusion required stable warfarin anticoagulation prior to 12 weeks of treatment with elbasvir–grazoprevir. A warfarin sensitivity index (WSI) was calculated at the start and end of treatment and 12 weeks after treatment. The primary endpoint was the difference in WSI from pre- to end-treatment. The secondary endpoint was the WSI difference from pretreatment to 12 weeks posttreatment. Changes in International Normalized Ratio, warfarin doses, and time in therapeutic range were measured. Results In the final sample of 43 patients, the mean WSI decreased during treatment from 0.53 to 0.40, or 25.2%. After treatment, the mean WSI rose to 0.51. Although the mean weekly warfarin dose increased from 40.3 to 44.6 mg during treatment, the mean International Normalized Ratio decreased from 2.40 to 1.96, recovering to 2.59 after treatment. The time spent in therapeutic range decreased from 74.1% before treatment to 39.8% during treatment and back to 64.9% 12 weeks posttreatment. Conclusion When elbasvir–grazoprevir was added to stable warfarin anticoagulation, warfarin sensitivity decreased significantly during treatment and returned to baseline after treatment.

Multi-Center Study of Thromboplastin Calibration Precision – Influence of Reagent Species, Composition, and International Sensitivity Index (ISI)

1993 ◽  
Vol 69 (01) ◽  
pp. 035-040 ◽  
Author(s):  
A M H P van den Besselaar ◽  
R M Bertina
Keyword(s):  
Oral Anticoagulants ◽  
International Normalized Ratio ◽  
The Other ◽  
World Health ◽  
Rabbit Brain ◽  
Sensitivity Index ◽  
Bovine Plasma ◽  
Significant Difference ◽  
The Mean ◽  
International Sensitivity Index

SummaryFour thromboplastin reagents were tested by 18 laboratories in Europe, North-America, and Australasia, according to a detailed protocol. One thromboplastin was the International Reference Preparation for ox brain thromboplastin combined with adsorbed bovine plasma (coded OBT/79), and the second was a certified reference material for rabbit brain thromboplastin, plain (coded CRM 149R). The other two thromboplastin reagents were another rabbit plain brain thromboplastin (RP) with a lower ISI than CRM 149R and a rabbit brain thromboplastin combined with adsorbed bovine plasma (RC). Calibration of the latter two reagents was performed according to methods recommended by the World Health Organization (W. H. O.).The purpose of this study was to answer the following questions: 1) Is the calibration of the RC reagent more precise against the bovine/combined (OBT/79) than against the rabbit/plain reagent (CRM 149R)? 2) Is the precision of calibration influenced by the magnitude of the International Sensitivity Index (ISI)?The lowest inter-laboratory variation of ISI was observed in the calibration of the rabbit/plain reagent (RP) against the other rabbit/plain reagent (CRM 149R) (CV 1.6%). The highest interlaboratory variation was obtained in the calibration of rabbit/plain (RP) against bovine/combined (OBT/79) (CV 5.1%). In the calibration of the rabbit/combined (RC) reagent, there was no difference in precision between OBT/79 (CV 4.3%) and CRM 149R (CV 4.2%). Furthermore, there was no significant difference in the precision of the ISI of RC obtained with CRM 149R (ISI = 1.343) and the rabbit/plain (RP) reagent with ISI = 1.14. In conclusion, the calibration of RC could be performed with similar precision with either OBT/79 or CRM 149R, or RP.The mean ISI values calculated with OBT/79 and CRM 149R were practically identical, indicating that there is no bias in the ISI of these reference preparations and that these reference preparations have been stable since their original calibration studies in 1979 and 1987, respectively.International Normalized Ratio (INR) equivalents were calculated for a lyophilized control plasma derived from patients treated with oral anticoagulants. There were small but significant differences in the mean INR equivalents between the bovine and rabbit thromboplastins. There were no differences in the interlaboratory variation of the INR equivalents, when the four thromboplastins were compared.

Inductive Effect of a Ritonavir-Containing Hepatitis C Treatment Regimen on Warfarin in a Patient—A Case Report

2018 ◽  
Vol 32 (4) ◽  
pp. 470-473 ◽  
Author(s):  
Audrey C. Rosene ◽  
Jaymee L. Gaspar
Keyword(s):  
Hepatitis C ◽  
Treatment Regimen ◽  
Case Reports ◽  
Warfarin Dose ◽  
International Normalized Ratio ◽  
Close Monitoring ◽  
Anticoagulation Management ◽  
Hepatitis C Treatment ◽  
History Of ◽  
Repeated Use

The warfarin management strategy for a mechanical mitral valve patient initiated on a ritonavir-based hepatitis C treatment regimen is described. A 62-year-old male with a past medical history of hepatitis C genotype 1a and stable warfarin dose history was initiated on a concomitant Viekira Pak® (VP) regimen containing ritonavir. Prior to initiation of the VP for hepatitis C treatment, the patient was stable on a warfarin dose of 40 mg/wk for 5 months. During treatment with VP, the patient experienced a markedly decreased international normalized ratio (INR) and warfarin requirements ultimately increased 125% from baseline (90 mg/wk). Effective anticoagulation management throughout and surrounding the treatment period for hepatitis C involved frequent warfarin dose adjustments, including preemptive changes, close monitoring, and repeated use of enoxaparin to ensure adequate thrombotic prophylaxis. This is believed to be the first reported case describing the management of warfarin in a patient with hepatitis C who received VP and required a drastically increased weekly warfarin dose. The possible mechanisms suggestive of this interaction and similar case reports in the literature are discussed.

Tu1656 Hepatitis C Treatment Initiation and Clinic Efficiency in the US Veterans Health Administration

2016 ◽  
Vol 150 (4) ◽  
pp. S1158
Author(s):  
Shari S. Rogal ◽  
Vera Yakovchenko ◽  
Rachel Gonzalez ◽  
Whitney Rockefeller ◽  
William Lukesh ◽  
...  
Keyword(s):  
Hepatitis C ◽  
Treatment Initiation ◽  
Veterans Health Administration ◽  
Veterans Health ◽  
Health Administration ◽  
Hepatitis C Treatment ◽  
Clinic Efficiency ◽  
The Us ◽  
Us Veterans

scholarly journals Analysis of a hepatitis C screening programme for US veterans

2005 ◽  
Vol 134 (2) ◽  
pp. 249-257 ◽  
Author(s):  
I. A. ZUNIGA ◽  
J. J. CHEN ◽  
D. S. LANE ◽  
J. ALLMER ◽  
V. E. JIMENEZ-LUCHO
Keyword(s):  
Risk Factors ◽  
Hepatitis C ◽  
Screening Programme ◽  
Medical Center ◽  
Liver Function Tests ◽  
Hcv Infection ◽  
Veterans Health ◽  
Health Administration ◽  
Screening Guidelines ◽  
Us Veterans

This study analyses a screening programme for hepatitis C virus (HCV) infection among US veterans in a suburban Veterans Affairs Medical Center, in New York. This is the first study examining all 11 potential risk factors listed in the 2001 National U.S. Veterans Health Administration Screening Guidelines. A retrospective study was conducted of 5400 veterans ‘at risk’ of HCV, identified through a questionnaire in this institution's primary-care outpatient departments between 1 October 2001 and 31 December 2003. Multivariate logistic regression models were built to identify independent predictors of infection. Of 2282 veterans tested for HCV, 4·6% were confirmed by HCV PCR to be HCV infected. In the multivariate model developed, injection drug use, blood transfusion before 1992, service during the Vietnam era, tattoo, and a history of abnormal liver function tests were independent predictors of HCV infection. Our data support considering a more targeted screening approach that includes five of the 11 risk factors.

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