N-(3',4'-dimethoxycinnamoyl)anthranillic acid, an antiallergic compound, induced eosinophilic cystitis.

Eosinophilic cystitis developed in an asthmatic patient after therapy with the antiasthmatic agent, Tranilast. The progress of this patient and the histopathologic findings of bladder biopsy specimens are reported. A review of recent publications on the possible causative correlations is presented. It appears judicious to perform bladder biopsy if common chemotherapy fails to improve bladder irritability in patients receiving Tranilast therapy. If a diagnosis of eosinophilic cystitis induced by Tranilast is established, immediate withdrawal of the drug with or without steroid therapy is recommended.