Efficacy of ketotifen in corticosteroid-dependent idiopathic anaphylaxis

To assess the potential benefit of ketotifen in the treatment of patients with corticosteroid-dependent idiopathic anaphylaxis, ketotifen was administered in an open trial to nine patients with idiopathic anaphylaxis who required maintenance prednisone for control of their disease. A double-blind trial was not done for reasons of patient safety. After a period of management with prednisone and establishment of the minimal dose of prednisone that controlled idiopathic anaphylaxis, ketotifen was initiated and cautious reduction of prednisone was attempted. The prednisone requirement was not altered in two patients, but prednisone was either substantially reduced or terminated in seven patients. Of these seven, three patients developed recurrent symptoms of idiopathic anaphylaxis after tapering and discontinuation of ketotifen, and ketotifen had to be resumed. The statistical analysis of prednisone reduction was highly significant (P less than .004) and we conclude ketotifen was of significant benefit in seven of nine patients with corticosteroid-dependent idiopathic anaphylaxis.