572440
research-article2015
AOPXXX10.1177/1060028015572440Annals of Pharmacotherapy
Letter to the Editor
Reply: Efficacy and Safety of Argatroban and Bivalirudin in Patients With Suspected Heparin-Induced Thrombocytopenia We thank Dr. Miyares for her comments in the accompanying editorial related to our recent publication on argatroban and bivalirudin in the management of suspected heparin-induced thrombocytopenia (HIT).1,2 Dr. Miyares emphasized the necessity of standardized protocols for argatroban given its dosing complexity. Though the Food and Drug Administration– approved argatroban starting dose for HIT is 2 µg/kg/min, as with other reviews, our study population required lower dosing to achieve the therapeutic activated partial thromboplastin time (aPTT) goal.3-5 The initial median (interquartile range) dose of 2.0 (0.64-2.0) µg/kg/min may have affected the time to therapeutic aPTT goal, but excessive anticoagulation may not have been reflected in time within therapeutic range as the author suggests; the mean ± SD percentage of aPTT values above goal were 15% ± 22% and 10% ± 15% (P = 0.613), whereas those below goal were 16% ± 20% and 6% ± 11% (P = 0.010) for argatroban and bivalirudin, respectively. To optimally use anticoagulants in a critical situation as HIT, we advocate for standardized protocols not only with argatroban but all comparative agents without fixed dosing. Our study aims to analyze real-life clinical practice of how patients with suspected HIT were managed at this tertiary care, academic medical center. Given the inherent limitations in a retrospective review, we agree that no definitive conclusions regarding inferiority or superiority may be drawn. Conducting a prospective comparative study where a majority of the variables can be controlled, including dosing through protocols or standardized order sets, would be ideal. Until then, a clinician may critically review the literature gathered from the existing paucity of data related to HIT treatment to determine the best care for his or her individual patient. Quynh-Anh T. Vo, PharmD Veterans Affairs Medical Center, San Francisco, CA, USA
Annals of Pharmacotherapy 2015, Vol. 49(4) 500 © The Author(s) 2015 Reprints and permissions: sagepub.com/journalsPermissions.nav DOI: 10.1177/1060028015572440 aop.sagepub.com
Joyce K. Lin, PharmD Veterans Affairs Medical Center, San Francisco, CA, USA University of California at San Francisco, CA, USA Lisa M. Tong, PharmD Veterans Affairs Medical Center, San Francisco, CA, USA University of California at San Francisco, CA, USA Declaration of Conflicting Interests The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding The author(s) received no financial support for the research, authorship, and/or publication of this article.
References 1. Miyares MA. Comment: efficacy and safety of argatroban and bivalirudin in patients with suspected heparin-induced thrombocytopenia. Ann Pharmacother. 2015;49:499. 2. Vo QT, Lin JK, Tong LM. Efficacy and safety of argatroban and bivalirudin in patients with suspected heparin-induced thrombocytopenia. Ann Pharmacother. 2015;49:178-184. 3. Smythe MA, Stephens JL, Koerber JM, Mattson JC. A comparison of lepirudin and argatroban outcomes. Clin Appl Thromb Hemost. 2005;11:371-374. 4. Kiser TH, Jung R, MacLaren R, Fish DN. Evaluation of diagnostic tests and argatroban or lepirudin therapy in patients with suspected heparin-induced thrombocytopenia. Pharmacotherapy. 2005;25:1736-1745. 5. Skrupky LP, Smith JR, Deal EN, et al. Comparison of bivalirudin and argatroban for the management of heparin-induced thrombocytopenia. Pharmacotherapy. 2010;30:1229-1238.
Downloaded from aop.sagepub.com at NANYANG TECH UNIV LIBRARY on November 14, 2015
research-article2015
AOPXXX10.1177/1060028015572440Annals of Pharmacotherapy
Letter to the Editor
Reply: Efficacy and Safety of Argatroban and Bivalirudin in Patients With Suspected Heparin-Induced Thrombocytopenia We thank Dr. Miyares for her comments in the accompanying editorial related to our recent publication on argatroban and bivalirudin in the management of suspected heparin-induced thrombocytopenia (HIT).1,2 Dr. Miyares emphasized the necessity of standardized protocols for argatroban given its dosing complexity. Though the Food and Drug Administration– approved argatroban starting dose for HIT is 2 µg/kg/min, as with other reviews, our study population required lower dosing to achieve the therapeutic activated partial thromboplastin time (aPTT) goal.3-5 The initial median (interquartile range) dose of 2.0 (0.64-2.0) µg/kg/min may have affected the time to therapeutic aPTT goal, but excessive anticoagulation may not have been reflected in time within therapeutic range as the author suggests; the mean ± SD percentage of aPTT values above goal were 15% ± 22% and 10% ± 15% (P = 0.613), whereas those below goal were 16% ± 20% and 6% ± 11% (P = 0.010) for argatroban and bivalirudin, respectively. To optimally use anticoagulants in a critical situation as HIT, we advocate for standardized protocols not only with argatroban but all comparative agents without fixed dosing. Our study aims to analyze real-life clinical practice of how patients with suspected HIT were managed at this tertiary care, academic medical center. Given the inherent limitations in a retrospective review, we agree that no definitive conclusions regarding inferiority or superiority may be drawn. Conducting a prospective comparative study where a majority of the variables can be controlled, including dosing through protocols or standardized order sets, would be ideal. Until then, a clinician may critically review the literature gathered from the existing paucity of data related to HIT treatment to determine the best care for his or her individual patient. Quynh-Anh T. Vo, PharmD Veterans Affairs Medical Center, San Francisco, CA, USA
Annals of Pharmacotherapy 2015, Vol. 49(4) 500 © The Author(s) 2015 Reprints and permissions: sagepub.com/journalsPermissions.nav DOI: 10.1177/1060028015572440 aop.sagepub.com
Joyce K. Lin, PharmD Veterans Affairs Medical Center, San Francisco, CA, USA University of California at San Francisco, CA, USA Lisa M. Tong, PharmD Veterans Affairs Medical Center, San Francisco, CA, USA University of California at San Francisco, CA, USA Declaration of Conflicting Interests The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding The author(s) received no financial support for the research, authorship, and/or publication of this article.
References 1. Miyares MA. Comment: efficacy and safety of argatroban and bivalirudin in patients with suspected heparin-induced thrombocytopenia. Ann Pharmacother. 2015;49:499. 2. Vo QT, Lin JK, Tong LM. Efficacy and safety of argatroban and bivalirudin in patients with suspected heparin-induced thrombocytopenia. Ann Pharmacother. 2015;49:178-184. 3. Smythe MA, Stephens JL, Koerber JM, Mattson JC. A comparison of lepirudin and argatroban outcomes. Clin Appl Thromb Hemost. 2005;11:371-374. 4. Kiser TH, Jung R, MacLaren R, Fish DN. Evaluation of diagnostic tests and argatroban or lepirudin therapy in patients with suspected heparin-induced thrombocytopenia. Pharmacotherapy. 2005;25:1736-1745. 5. Skrupky LP, Smith JR, Deal EN, et al. Comparison of bivalirudin and argatroban for the management of heparin-induced thrombocytopenia. Pharmacotherapy. 2010;30:1229-1238.
Downloaded from aop.sagepub.com at NANYANG TECH UNIV LIBRARY on November 14, 2015
