Old Drug or New?

Determining which drug works better for which patients

By Mayo Clinic Staff

To the average TV viewer, it may seem like new drugs flood the marketplace daily.

However, from the 1950s until just recently, warfarin was the only available anticoagulant drug approved by the Food and Drug Administration (FDA) to prevent blood clotting. One of the most common reasons people take an anticoagulant is to reduce stroke and heart attack risk related to atrial fibrillation, an irregular and often rapid heart rate that commonly causes poor blood flow. The condition affects 3 million Americans.

Warfarin is so powerful and long-acting, though, that it may reduce beneficial clotting. Users must have regular blood tests to ensure they don't experience excessive bleeding, especially in the gastrointestinal (GI) tract, where it can be life-threatening.

Three new oral anticoagulants received FDA approval in just the past few years, and two of them — dabigatran (Pradaxa) and rivaroxaban (Xarelto) — do not require regular trips to the doctor's office for blood monitoring. That convenience factor has caused a huge upswing in prescriptions, even though the newer medications can be more expensive than warfarin.

Although cost and convenience are important considerations, researchers at the Mayo Clinic Robert D. and Patricia E. Kern Center for the Science of Health Care Delivery wondered if physicians had the medical evidence they needed to prescribe the best anticoagulant on an individual basis. The team first focused on addressing the relative risks associated with taking the drugs at different ages.

"In our study, by using real-world, national data available from the OptumLabs data warehouse, we were able to determine that individuals over age 75 have a much higher risk of GI bleeds than younger patients if using dabigatran or rivaroxaban instead of warfarin," says lead author Neena S. Abraham, M.D., the center's associate medical director in Arizona. "Our findings definitely point toward important age-related risk that merits consideration when doctors are making treatment recommendations.

"We also saw that for patients under age 65, the newer agents appear to carry less risk of GI bleeds. At 65 this changes, and risk begins to increase until it exceeds the GI bleeding risk with warfarin at age 76 and older."

On an individual level, these findings can help guide the best medication choice and, on a national level, better inform conversations about health care value.

Safer, higher value care. Your gift makes it happen.

Jan. 12, 2016