Localization of the anti-allergic agent tranilast in the urinary bladder of rats as demonstrated by light microscopic radioautography.

Tranilast (N-(3,4-dimethoxycinnamoyl)anthranilic acid), an anti-allergic drug, has been developed and used for the treatment of anaphylactic hypersensitivity such as bronchial asthma in Japan. Recently, many cases with eosinophilic cystitis associated with administration of this drug have been reported. In a series of studies to elucidate the pathoetiology of this unusual cystitis, the distribution of tranilast in urinary bladder of rats was investigated. Light microscopic radioautography using tritiated tranilast showed that this drug was localized specifically in the transitional epithelial cells of the mucosa and the endothelial cells of venous vessels for a fairly long time after an oral administration. These results should be taken into consideration in further studies of this drug-associated cystitis.