Choosing the most beneficial blood thinner

Q. There seem to be many options when a person needs a blood thinner. How do doctors decide?

A. "Blood thinners" don't actually make the blood less viscous. The term refers to medications that help prevent unwanted blood clots. The two main categories are anticoagulants and antiplatelet drugs.

For decades, the only available oral anticoagulant was warfarin (Coumadin). Warfarin acts by partially inhibiting the liver from producing vitamin K–dependent clotting factors. The newer anticoagulants work directly on specific clotting proteins. That's why they are called direct-acting oral anticoagulants (DOACs). They include apixaban (Eliquis), dabigatran (Pradaxa), edoxaban (Savaysa), and rivaroxaban (Xarelto).

For the majority of people with atrial fibrillation (afib, a heart rhythm disorder), deep-vein thrombosis (DVT, a dangerous blood clot deep in the body, typically in a leg vein), or pulmonary embolism (a blood clot in the lung), DOACs are the preferred oral therapy. In general, they are more effective, safer, and easier to manage than warfarin. Unlike warfarin, DOACs have consistent dosing schedules, don't require regular blood test monitoring, and rarely interact with food or other medications.

However, DOACs are more expensive than warfarin and may not be covered by insurance. Also, some people who have taken warfarin for years stay consistent with their diet and have little variation in their blood test results. So, they rarely require changes in dose.

For certain situations, warfarin remains the best oral anticoagulant option. In people who have a mechanical heart valve, DOACs cannot reliably prevent clotting on the valve. Warfarin is also strongly preferred for people who have valve damage from rheumatic fever, those who have antiphospholipid syndrome (an uncommon condition that leads to blood clots), and those who have undergone transcatheter aortic valve replacement.

Most doctors prescribe the DOACs apixaban or rivaroxaban. Apixaban needs to be taken every 12 hours, while rivaroxaban is taken once daily. Ideally, they both should be taken at the same times each day.

In general, doctors prescribe antiplatelet drugs, such as aspirin and clopidogrel (Plavix), to help prevent arterial blood clots that can lead to a heart attack or stroke. However, an anticoagulant (a DOAC or warfarin) is better than an antiplatelet drug for preventing stroke in people with atrial fibrillation.

Some people with afib and coronary artery disease need to take both an anticoagulant and an antiplatelet drug. Because combining the two boosts the risk of unwanted bleeding, any sign of excess bruising or prolonged bleeding of a cut should be reported to your doctor.

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