The US Food and Drug Administration today approved Pradaxa capsules (dabigatran etexilate) for the prevention of stroke and blood clots in patients with abnormal heart rhythm (atrial fibrillation).

Atrial fibrillation, which affects more than 2 million Americans, involves very fast and uncoordinated contractions of the heart’s two upper heart chambers (atria) and is one of the most common types of abnormal heart rhythm.

“People with atrial fibrillation are at a higher risk of developing blood clots, which can cause a disabling stroke if the clots travel to the brain,” said Norman Stockbridge, director of the Division of Cardiovascular and Renal Products in the FDA’s Center for Drug Evaluation and Research.

Pradaxa is an anticoagulant that acts by inhibiting thrombin, an enzyme in the blood that is involved in blood clotting. The safety and efficacy of Pradaxa were studied in a clinical trial comparing Pradaxa with the anticoagulant warfarin. In the trial, patients taking Pradaxa had fewer strokes than those who took warfarin.

“Unlike warfarin, which requires patients to undergo periodic monitoring with blood tests, such monitoring is not necessary for Pradaxa,” Stockbridge says.

As with other approved anti-clotting drugs, bleeding, including life-threatening and fatal bleeding, was among the most common adverse reactions reported by patients treated with Pradaxa. Gastrointestinal symptoms, including an uncomfortable feeling in the stomach (dyspepsia), stomach pain, nausea, heartburn, and bloating also were reported.

Pradaxa was approved with a Medication Guide that informs patients of the risk of serious bleeding. The guide will be distributed each time a patient fills a prescription for the medication.

Pradaxa, manufactured by Boehringer Ingelheim Pharmaceuticals Inc, will be available in 75 milligram and 150 milligram capsules.