EAST ST. LOUIS, Ill. — German drugmaker Boehringer Ingelheim said Wednesday it has agreed to pay $650 million to settle thousands of U.S. claims questioning the marketing and safety of its popular blood thinner Pradaxa.

The company said the settlement, filed in federal court in East St. Louis, resolves roughly 4,000 claims, paying out an average of $162,500 per case.

The drug, known chemically as dabigatran, was approved in October 2010 by the U.S. Food and Drug Administration as a treatment to reduce the stroke risk in patients with irregular heartbeats, or atrial fibrillation. Pradaxa works by stopping the enzyme involved in blood clotting.

But the plaintiffs had argued the company didn’t adequately warn Pradaxa users of the risks, including severe or in many cases fatal bleeding blamed on the anticoagulant. Unlike other blood-thinning medications, those behind the lawsuits said, there is no known reversal agent or antidote for Pradaxa, an alternative to decades-old warfarin.

Boehringer Ingelheim, based in Ingelheim, Germany, stands “resolutely” behind Pradaxa “and believed from the outset that the plaintiffs’ claims lacked any merit,” the company’s global general counsel said in a statement.

“Time and again the benefits and safety of Pradaxa have been confirmed in many clinical trials and in real-world data analyses,” Andreas Neumann added. “This settlement does not change the facts about Pradaxa or its importance to patients.”