A new US Food and Drug Administration (FDA) study compared the risks, benefits and effectiveness of these medications.
Compared to warfarin (brand names Coumadin, Jantoven), Pradaxa carried fewer risks of blood clot-related strokes, bleeding in the brain and death, but more risks of major gastrointestinal bleeding, according to the new FDA study.
Heart attack risks of both medications were roughly the same, the FDA researchers found.
The FDA cautioned those now taking Pradaxa against stopping use of the medication on their own. Patients should talk with their doctors about these medication safety concerns, the researchers wrote.
"Ask a pharmacist about your medication's side effects."
For this study, FDA researchers reviewed the insurance claims of 134,000 Medicare patients aged 65 and older. These patients represented a larger and older group of patients than were involved in the FDA’s prior investigation of Pradaxa and warfarin. The 134,000 patients were new users of Pradaxa and warfarin.
The previous FDA comparison of warfarin and Pradaxa analyzed those medications’ effects on 10,000 patients. Two-thirds (64 percent) of those 10,000 people were at least 65 years old, the age when individuals can qualify for Medicare, the federal government’s health care for older adults.
Not only was this new study of 134,000 substantially larger, it also used a more refined model for measuring the results of using of warfarin and Pradaxa, the researchers wrote.
The new safety report follows a November 2012 FDA statement in which the FDA concluded that bleeding risks were not higher for Pradaxa users than for warfarin users.
The FDA announced that it plans to release the fully detailed 134,000-patient study about increased bleeding risks with Pradaxa. For now, it has issued only this preliminary safety guideline.
“As a result of our latest findings, we still consider Pradaxa to have a favorable benefit to risk profile and have made no changes to the current label or recommendations for use. Patients should not stop taking Pradaxa (or warfarin) without first talking with their health care professionals. Stopping the use of blood-thinning medications such as Pradaxa and warfarin can increase the risk of stroke and lead to permanent disability and death,” the FDA announced.
The FDA has asked health care professionals and their patients to report side effects related to use of Pradaxa or warfarin through the FDA MedWatch Online Voluntary Reporting Form.
From October 2010, when Pradaxa became available through pharmacies, to December 2013, roughly 943,000 patients were prescribed Pradaxa, according to the FDA.