Procainamide-induced lupus anticoagulant.

The lupus anticoagulant, with or without other symptoms or signs of lupus, has been described in patients taking procainamide. Screening all such patients for the presence of these anticoagulants may be warranted (despite the rarity of episodes of bleeding) in view of the potentially increased risk of thrombotic events in patients who may already be predisposed. A prospective study to determine the incidence of lupus anticoagulant in procainamide-treated patients and the true frequency of thrombosis in these patients would be helpful in determining appropriate management.