Few things are better in medicine than having an effective and cheap medication with multiple indications; enter the 70-year-old rodenticide (yes, that was its original indication), warfarin. DVT? Warfarin. PE? Warfarin. Afib? Warfarin. LV thrombus? Warfarin. Mechanical valve? Warfarin. Coagulopathy? Warfarin. And the list goes on…
At around 15 cents a pill and with a long list of indications, it is common practice for correctional facilities to use warfarin as their first line for anticoagulation. But is this “best practice” in line with “community standards”? The answer is “NO”!
The Challenges of Warfarin
Despite its cheap cost, warfarin requires routine coagulation monitoring because genetic variation, as well as its interaction with food, other drugs, and comorbidities produce variable and unpredictable anticoagulation effects. The “time in therapeutic range” is a determinant of the efficacy and safety of warfarin, and multiple studies have shown that a patient is only within the therapeutic window roughly 60% of the time. It can be surmised that this number is likely even lower in a correctional environment. Thus, more than 40% of the time, an inmate-patient with a serious disease wouldn’t be appropriately receiving treatment as they’d be outside the therapeutic window. Furthermore, being too low puts them at risk of the disease they are being treated for, and being too high puts them at risk of serious bleeding episodes.
Warfarin vs. DOACs
So, what do we do? First approved in 2010, direct oral anticoagulants (DOACs) have rapidly become the gold standard for anticoagulation. DOACs have a more rapid onset, predictable anticoagulant effect, shorter half-life, and few drug-drug and dietary interactions. Thus, they can be given in fixed doses without routine coagulation monitoring. Furthermore, numerous studies, such as Direct Oral Anticoagulants Versus Warfarin in Patients With Atrial Fibrillation… published in Circulation Vol 145 Issue 4, have shown statistical significance in the reduction of recurrent venous thromboembolism (VTE), ischemic stroke, hemorrhagic stroke, and all-cause death while additional studies have shown reduced risks of major bleeding and intracranial hemorrhage compared to warfarin. This data shows statistically significant superiority. (It is important to note that there are a few indications for which warfarin remains the best option over DOACs, such as valvular afib, high risk of GI bleeding, and triple positive antiphospholipid syndrome. The use of warfarin in these instances is appropriate and is considered best practice, as it falls in line with community standards and evidence-based research.)
So, why is warfarin being used as first-line anticoagulation in correctional facilities? Short answer: Cost. Whereas warfarin is 15 cents per pill, DOACs can cost around $20 per pill, a difference of 13,333%! But does this cost difference justify this practice? To me, the answer is no. Within corrections, we have an obligation to practice the same evidence-based medicine being utilized in the community. No longer is warfarin the preferred drug (except for a few specific instances) in the community, and thus, it should no longer be the preferred drug in corrections, regardless of the cost.
Dr. Nicholas Longnecker, MD CCHP CMO
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