Abstract
BackgroundDabigatran etexilate may be underutilized in geriatric patients because of inadequate clinical experience in individuals with severe renal impairment and post-marketing reports of bleeding events. Assessing the degree of anticoagulation may improve the risk:benefit ratio for dabigatran. The aim of this prospective study was to identify whether therapeutic drug monitoring of dabigatran anticoagulant activity using a chromogenic anti-factor IIa assay is a viable option for therapy individualization.MethodsPlasma dabigatran concentration was assessed in nine patients with nonvalvular atrial fibrillation aged 75 years or older currently receiving dabigatran etexilate for prevention of stroke, using an anti-factor IIa chromogenic assay and HPLC-MS/MS. Trough concentrations were evaluated on two separate occasions to determine intrapatient variation.ResultsBlood was collected at 13.1 ± 2.3 h (mean ± SD) post dose from patients prescribed dabigatran etexilate 150 mg twice daily (5/9 patients) or dabigatran etexilate 75 mg twice daily (4/9 patients). Results from the anti-factor IIa chromogenic assay correlated with dabigatran concentrations as assessed by HPLC-MS/MS (r2 = 0.81, n = 16). There was no correlation between dabigatran trough values taken at separate visits (r2 = 0.002, n = 7). Furthermore, there was no correlation found between the drug concentrations and patients’ renal function determined by both creatinine and cystatin-C based equations. None of the patients enrolled in the study were in the proposed on-therapy trough range during at least one visit.ConclusionThe chromogenic anti-factor IIa assay demonstrated similar performance in quantifying dabigatran plasma trough concentrations to HPLC-MS/MS. Single measurement of dabigatran concentration by either of two methods during routine visits may not be reliable in identifying patients at consistently low or high dabigatran concentrations.Electronic supplementary materialThe online version of this article (doi:10.1186/s12959-016-0084-2) contains supplementary material, which is available to authorized users.
Highlights
Dabigatran etexilate may be underutilized in geriatric patients because of inadequate clinical experience in individuals with severe renal impairment and post-marketing reports of bleeding events
Dabigatran possesses many of the attributes of an ideal anticoagulant for stroke prevention in nonvalvular atrial fibrillation (NVAF) including predictable pharmacokinetics and lack of the requirement for routine monitoring [1,2,3]
The landmark Randomized Evaluation of LongTerm Anticoagulation Therapy (RE-LY) trial found dabigatran etexilate 150 mg twice daily to be superior to Brunetti et al Thrombosis Journal (2016) 14:10 warfarin; it has been difficult to extrapolate the results to the geriatric population or to patients with severe renal impairment
Summary
Dabigatran etexilate may be underutilized in geriatric patients because of inadequate clinical experience in individuals with severe renal impairment and post-marketing reports of bleeding events. Dabigatran etexilate is underutilized in geriatric patients because of insufficient clinical experience with dosing recommendations in severe renal impairment and post-marketing reports of bleeding complications [6,7,8, 12,13,14,15,16,17,18]. The European Medicines Agency (EMA) considers dabigatran etexilate as contraindicated in patients with a CrCl < 30 mL/min and patients with a CrCl < 50 mL/min should receive 110 mg twice daily [24] These data suggest that the ability to gauge the degree of anticoagulation in the geriatric patient population may be beneficial
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