Dabigatran (Pradaxa) should not be prescribed to prevent blood clots or stroke in patients with mechanical heart valves, the FDA warned.

The warning follows the termination of a European clinical trial in which patients taking dabigatran had more frequent thromboembolic events than those on warfarin. Dabigatran patients also experienced more bleeding after valve surgery.

Patients with mechanical heart valves should be transitioned from dabigatran to another anticoagulant, the FDA recommends; stopping dabigatran use suddenly can increase blood clot and stroke risk.

Source: FDA MedWatch safety alert