Novel Oral Anticoagulants Wrongly Dosed in the ICU

One-third of patients receiving a novel oral anticoagulant (NOAC) were on an inappropriate dose at some point during their stay in the intensive care unit (ICU), according to a new study.

Researchers at Fairleigh Dickinson University (FDU; Teaneck, NJ, USA) conducted a retrospective chart review involving 21 adult patients between June 2013 and May 2014, who received one of the then approved NOAC agents—apixaban (Eliquis, 33% of the study population), rivaroxaban (Xarelto, 43%), or dabigatran (Pradaxa, 24%)—in the ICU. Three-quarters of the patients had nonvalvular atrial fibrillation (AF) as the indication for NOAC medication; the rest of the patients received them for treatment or prevention of venous thromboembolism (VTE).

The results showed that seven of the NOAC ICU patients were dosed incorrectly, with failure to take account of renal function implicated in six of them. For rivaroxaban, one inappropriate dosing case was due to drug interactions in the presence of severe renal impairment, while the other was incorrect dose for the indication. The two cases of inappropriate dabigatran dosing, and all three apixaban cases, were due to incorrect dosing due to renal function impairment. A lone bleeding event occurred, and no patients required hemodialysis or prothrombin complex concentrate. The study was presented at the Society of Critical Care Medicine (SCCM) meeting, held during January 2015 in Phoenix (AZ, USA).

“Because renal function is so often impaired in this population and can change rapidly, it might be worthwhile to develop a trigger notification in the electronic medical record to alert the ICU team to potential NOAC dosing problems when creatinine clearance drops below a certain level,” concluded lead author Julie Kalabalik, PharmD, of the FDU school of pharmacy, and colleagues.

Until the introduction of NOACs, warfarin was the main treatment option for long-term control of patients with AF, VTE, or other conditions that require chronic anticoagulation. The major benefit of the NOAC anticoagulants is that they do not require strict and frequent laboratory monitoring, dosing adjustments, or dietary restrictions, and incur fewer drug interactions than warfarin. On the other hand, they do not have specific reversal agents, may require dosage adjustment based on patient renal function, and lack clinical data regarding their long-term safety and efficacy.

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