As a hospital pharmacist, you will get questions about using direct oral anticoagulants (DOACs) for heparin-induced thrombocytopenia (HIT). We usually treat HIT with IV argatroban or sometimes IV bivalirudin or subcutaneous fondaparinux (Arixtra). Then we transition to warfarin (Marevan) once the platelet count recovers, usually 150,000/mm3 or higher. Now there's growing interest in using a DOAC to treat HIT. But data are limited, especially when considering DOACs as initial HIT treatment.
Continue to start with a non-heparin parenteral anticoagulant in HIT patients who are critically ill or have limb-threatening thrombosis. For now, lean toward starting a non-heparin parenteral anticoagulant in most HIT patients with any thrombosis due to limited DOAC data. When transitioning from a parenteral anticoagulant, consider a DOAC over warfarin. DOACs don't require overlap. And issues such as argatroban falsely elevating the INR can make warfarin more challenging. Plus it's okay to start a DOAC before the platelet count recovers.
Check for reasons to avoid a DOAC, such as renal dysfunction (apixaban with low dose may be used in renal dysfunction) or a mechanical valve. And keep in mind that DOACs may be cost. Use rivaroxaban (Xarelto) or apixaban (Eliquis). They have the most HIT data and don't require initial parenteral anticoagulant treatment like other DOACs.
In a stable HIT patient withOUT a thrombosis, consider STARTING treatment with a DOAC either rivaroxaban (Xarelto, Rivarospire) or apixaban (Eliquis). Order VTE treatment doses for HIT patients with OR without a clot. For example, use rivaroxaban (Xarelto) 15 mg BID for 21 days, then 20 mg daily. Treat HIT patients with a thrombosis for at least 3 months. But consider limiting treatment to 4 weeks for HIT patients without a clot. Data are limited, but this seems to be the time of greatest risk. Get our note "Heparin-induced thrombocytopenia (HIT)" for more details.
REFERENCES
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Cuker A, Arepally GM, Chong BH, Cines DB, Greinacher A, Gruel Y, Linkins LA, Rodner SB, Selleng S, Warkentin TE, Wex A, Mustafa RA, Morgan RL, Santesso N. American Society of Hematology 2018 guidelines for management of venous thromboembolism: heparin-induced thrombocytopenia. Blood Adv. 2018 Nov 27;2(22):3360-3392. Available at: https://ashpublications.org/bloodadvances/article/2/22/3360/16129/American-Society-of-Hematology-2018-guidelines-for
Warkentin TE, Pai M, Linkins LA. Direct oral anticoagulants for treatment of HIT: update of Hamilton experience and literature review. Blood. 2017 Aug 31;130(9):1104-1113. Available at: https://ashpublications.org/blood/article/130/9/1104/36991/Direct-oral-anticoagulants-for-treatment-of-HIT
Shatzel JJ, Crapster-Pregont M, Deloughery TG. Non-vitamin K antagonist oral anticoagulants for heparin-induced thrombocytopenia. A systematic review of 54 reported cases. Thromb Haemost. 2016 Aug 1;116(2):397-400. Available at: https://www.thieme-connect.de/products/ejournals/abstract/10.1160/TH16-02-0101