571727
research-article2015
AOPXXX10.1177/1060028015571727Annals of Pharmacotherapy
Letter to the Editor
Comment: Efficacy and Safety of Argatroban and Bivalirudin in Patients With Suspected Heparin-Induced Thrombocytopenia Vo et al1 should be applauded for their research regarding analysis of argatroban and bivalirudin in the management of suspected heparin-induced thrombocytopenia (HIT). Although the report concludes that bivalirudin achieved the therapeutic activated partial thromboplastin time (aPTT) goal more expeditiously than argatroban, this conclusion may inadvertently be misinterpreted to denote that bivalirudin is a superior agent. Although the authors acknowledge that no protocol was used to standardize the choice of anticoagulant, dosage, and monitoring, there are certain aspects of this study worthy of clarification. As depicted in multiple studies, supratherapeutic levels and excessive anticoagulation may occur with Food and Drug Administration (FDA)-approved doses (ie, 2 µg/kg/min) of argatroban, even in patients who lack evidence of hepatic dysfunction.2-5 As the current study demonstrated, a median dose of 1 µg/kg/min of argatroban was required to achieve therapeutic goal aPTT. Additionally, the initial dosing selection of 2 µg/kg/min may have precipitated a delay in achievement of therapeutic aPTT. Furthermore, the complexity of argatroban dosing extends beyond the initial dose. Currently, many hospitals have implemented argatroban dose adjustment nomograms to correct aPTT results when not within therapeutic range. Without such protocols, lack of standardization may lead to suboptimal anticoagulation, resulting in bleeding, thrombotic events, and the assumption that other anticoagulants are equally or more effective. Results of this and other studies should illustrate the necessity of hastening standardization of protocols for the management of HIT and call on the FDA to review and possibly revise dosing recommendations for argatroban to optimize the safety and overall effectiveness of this agent. Until then, comparative studies of argatroban versus other
Annals of Pharmacotherapy 2015, Vol. 49(4) 499 © The Author(s) 2015 Reprints and permissions: sagepub.com/journalsPermissions.nav DOI: 10.1177/1060028015571727 aop.sagepub.com
anticoagulants should be deemed premature and results viewed with caution. Marta A. Miyares, PharmD Pharmacy Department, Jackson Memorial Hospital, Miami, USA [email protected] Declaration of Conflicting Interests The author declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding The author received no financial support for the research, authorship, and/or publication of this article.
References 1. Vo QT, Lin JK, Tong LM. Analysis of argatroban and bivalirudin in the management of suspected heparin-induced thrombocytopenia. Ann Pharmacother. 2015;49:178-184. 2. Keegan SP, Gallagher EM, Ernst NE, Young EJ, Mueller EW. Effects of critical illness and organ failure on therapeutic argatroban dosage requirements in patients with suspected or confirmed heparin-induced thrombocytopenia. Ann Pharmacother. 2009;43:19-27. 3. Arpino PA, Hallisey RK. Effect of renal function on the pharmacodynamics of argatroban. Ann Pharmacother. 2004;38: 25-29. 4. Verme-Gibboney CN, Hursting MJ. Argatroban dosing in patients with heparin-induced thrombocytopenia. Ann Pharmacother. 2003;37:970-975. 5. Reichert MG, MacGregor DA, Kincaid EH, Dolinski SY. Excessive argatroban anticoagulation for heparin-induced thrombocytopenia. Ann Pharmacother. 2003;37:652-654.
Downloaded from aop.sagepub.com at UNIV NEBRASKA LIBRARIES on June 5, 2016
research-article2015
AOPXXX10.1177/1060028015571727Annals of Pharmacotherapy
Letter to the Editor
Comment: Efficacy and Safety of Argatroban and Bivalirudin in Patients With Suspected Heparin-Induced Thrombocytopenia Vo et al1 should be applauded for their research regarding analysis of argatroban and bivalirudin in the management of suspected heparin-induced thrombocytopenia (HIT). Although the report concludes that bivalirudin achieved the therapeutic activated partial thromboplastin time (aPTT) goal more expeditiously than argatroban, this conclusion may inadvertently be misinterpreted to denote that bivalirudin is a superior agent. Although the authors acknowledge that no protocol was used to standardize the choice of anticoagulant, dosage, and monitoring, there are certain aspects of this study worthy of clarification. As depicted in multiple studies, supratherapeutic levels and excessive anticoagulation may occur with Food and Drug Administration (FDA)-approved doses (ie, 2 µg/kg/min) of argatroban, even in patients who lack evidence of hepatic dysfunction.2-5 As the current study demonstrated, a median dose of 1 µg/kg/min of argatroban was required to achieve therapeutic goal aPTT. Additionally, the initial dosing selection of 2 µg/kg/min may have precipitated a delay in achievement of therapeutic aPTT. Furthermore, the complexity of argatroban dosing extends beyond the initial dose. Currently, many hospitals have implemented argatroban dose adjustment nomograms to correct aPTT results when not within therapeutic range. Without such protocols, lack of standardization may lead to suboptimal anticoagulation, resulting in bleeding, thrombotic events, and the assumption that other anticoagulants are equally or more effective. Results of this and other studies should illustrate the necessity of hastening standardization of protocols for the management of HIT and call on the FDA to review and possibly revise dosing recommendations for argatroban to optimize the safety and overall effectiveness of this agent. Until then, comparative studies of argatroban versus other
Annals of Pharmacotherapy 2015, Vol. 49(4) 499 © The Author(s) 2015 Reprints and permissions: sagepub.com/journalsPermissions.nav DOI: 10.1177/1060028015571727 aop.sagepub.com
anticoagulants should be deemed premature and results viewed with caution. Marta A. Miyares, PharmD Pharmacy Department, Jackson Memorial Hospital, Miami, USA [email protected] Declaration of Conflicting Interests The author declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding The author received no financial support for the research, authorship, and/or publication of this article.
References 1. Vo QT, Lin JK, Tong LM. Analysis of argatroban and bivalirudin in the management of suspected heparin-induced thrombocytopenia. Ann Pharmacother. 2015;49:178-184. 2. Keegan SP, Gallagher EM, Ernst NE, Young EJ, Mueller EW. Effects of critical illness and organ failure on therapeutic argatroban dosage requirements in patients with suspected or confirmed heparin-induced thrombocytopenia. Ann Pharmacother. 2009;43:19-27. 3. Arpino PA, Hallisey RK. Effect of renal function on the pharmacodynamics of argatroban. Ann Pharmacother. 2004;38: 25-29. 4. Verme-Gibboney CN, Hursting MJ. Argatroban dosing in patients with heparin-induced thrombocytopenia. Ann Pharmacother. 2003;37:970-975. 5. Reichert MG, MacGregor DA, Kincaid EH, Dolinski SY. Excessive argatroban anticoagulation for heparin-induced thrombocytopenia. Ann Pharmacother. 2003;37:652-654.
Downloaded from aop.sagepub.com at UNIV NEBRASKA LIBRARIES on June 5, 2016
