Oral anticoagulants — blood thinners — are commonly prescribed for prevention of stroke due to mechanical heart valves or an irregular heart beat called atrial fibrillation (“afib”), or for treatment of blood clots.
Anticoagulation therapy can save lives for patients who have blood clots or are at high risk for them. However, the arrival of a new class of anticoagulants creates a confusing array of choices. Here are some anticoagulation basics to help you navigate.
All blood thinners cause an increased risk of bleeding — sometimes life-threatening — but that shouldn’t prevent doctors from prescribing it or patients from taking it. One-third of United States patients with afib who need anticoagulation aren’t receiving it, according to a recently published major study.
With a 50-year track record, warfarin is the traditional option. For patients well managed on warfarin, it can be safe and effective. However, warfarin requires some trial and error to determine the most effective dose while minimizing bleeding hazards, initially requiring frequent (every few days to weekly) lab monitoring (called INR) and can be affected by factors like age, diet and other medications you are taking.
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In the last five years, there have been four direct oral anticoagulants approved in the United States: apixaban, dabigatran, edoxaban and rivaroxaban. When compared to warfarin in major clinical trials, these DOACs were equally effective and demonstrated a lower incidence of major bleeding. DOACs have other advantages, including no need for routine lab monitoring, fewer drug and diet interactions, and more predictable dosing.
But DOACs still have a risk of bleeding and patients should routinely see a healthcare provider to check for compliance, drug interactions, and any changes in kidney or liver function, since DOACs can have some associated adverse effects. Also, DOACs are more expensive than warfarin, although manufacturers offer assistance programs to qualified patients that can help defray costs.
If a patient on the DOAC dabigatran experiences severe bleeding, a recently approved drug can help reverse that, and an antidote for the other three DOACs may be available soon.
While DOACs are effective, patients already taking warfarin shouldn’t automatically switch to a DOAC, especially if they are tolerating warfarin well.
Now more than ever, if your doctor wants you to begin taking a blood thinner, discussing the different options available is important. This discussion can educate you about the benefits of preventing blood clots versus risk of bleeding.
As always, don’t ever stop or make changes to any medication you’ve been prescribed without telling your healthcare provider.
Dr. George Davis is Anticoagulation Program Pharmacist Coordinator with UK HealthCare Pharmacy Services and the Gill Heart Institute, and Associate Adjunct Professor at the University of Kentucky College of Pharmacy.