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Researchers are learning how different anticoagulants stack up against warfarin. Getty Images
  • A new study examines how new anticoagulants compare with the drug warfarin in terms of effectiveness and safety.
  • People with valvular atrial fibrillation (AFib), or irregular heartbeat, had lower risk for major bleeding events when given these newer anticoagulants than people given warfarin.
  • The major downside of these newer drugs is that they cost significantly more than warfarin.

The anticoagulant warfarin, widely prescribed under the brand names Coumadin and Jantoven, has been a frontline medication for treating blood clots and preventing strokes since the 1950s.

But a large, new study suggests that people who have valvular atrial fibrillation (AFib), or irregular heartbeat, had lower risk for ischemic stroke or systemic embolism and major bleeding events when given newer direct oral anticoagulants (DOACs) than people given warfarin.

The researchers from the Perelman School of Medicine at the University of Pennsylvania included 55,000 people with AFib in their study, which published March 30 in the Annals of Internal Medicine.

Lead study author Ghadeer Dawwas, PhD, a postdoctoral fellow in the department of epidemiology, biostatistics, and informatics at the Perelman School of Medicine, told Healthline that the findings “support the use of direct oral anticoagulants in patients with atrial fibrillation” and valve-related heart diseases to prevent certain major health issues, including ischemic stroke or systemic embolism, without also drastically increasing the risk of bleeding complications.

“DOACs can be an effective and safe alternative to warfarin in patients with valvular atrial fibrillation and may provide treatment options in patients who receive suboptimal benefits from warfarin therapy,” Dawwas said.

Dr. Sanjiv Patel, an interventional cardiologist at MemorialCare Heart & Vascular Institute at Orange Coast Medical Center in Fountain Valley, California, told Healthline that the findings are consistent with past research comparing warfarin with DOACs.

The major strength of this new research is its population size.

“It’s what I have seen as well in my own practice,” said Patel, referring to equal or superior effectiveness for DOACs, “and the amount of bleeding in the brain or gastrointestinal system is less.”

“Overall, [DOACs] are much better,” he said.

Warfarin, originally derived from spoiled sweet clover plants, is part of a class of drugs called vitamin K antagonists (VKAs).

VKAs are highly effective anticoagulants, but they do come with risks, including excessive bleeding, negative interactions with a number of other drugs and food, and highly variable in how people respond to doses.

The drug also has a narrow window of therapeutic use. It can take 4 to 5 days for warfarin to take effect. Its use must be carefully monitored to ensure that it achieves the desired anti-clotting action without causing excessive bleeding.

“Coumadin requires monthly INR blood tests and adjustment of dosing dependent on diet and addition of other medications such as antibiotics,” said Dr. Victoria Shin, a cardiologist with the Torrance Memorial Medical Center in Torrance, California.

This type of maintenance and monitoring may be challenging for some people to upkeep.

Emergency room visits for complications aren’t uncommon among people taking warfarin. And fear of bleeding has led to the drug being underutilized among people with AFib.

DOACs inhibit the proteins involved in the process of blood clotting.

Warfarin inhibits the body using vitamin K to make clotting factors.

Dabigatran (Pradaxa), rivaroxaban (Xarelto), apixaban (Eliquis), and edoxaban (Savaysa) are among the DOACs that have been studied, marketed, and prescribed as alternatives to VKAs like warfarin.

In this latest study, researchers looked at data from a practice-based commercial healthcare database.

They concluded that use of rivaroxaban and apixaban was associated with greater effectiveness and fewer bleeding events compared with warfarin.

Dabigatran, on the other hand, resulted in fewer bleeding events but was no more effective than warfarin.

The major downside of DOACs is that they cost significantly more than warfarin.

“We hope this would encourage insurance companies to provide more coverage for these agents given their superior efficacy and lower risk of bleeding,” Shin told Healthline.