[The so-called dihydralazine hepatitis. A contribution to the pathogenesis].

Liver injuries following application of dihydralazine in 14 patients, ten of them with the typical pattern of perivenous liver cell necrosis, are reported. The other 4 patients, all having been exposed to additional hepatotoxic substances, histologically showed mixed patterns of tissue injury in liver biopsy. Moreover, in 6 of 14 patients there were diseases in the upper abdomen and/or metabolic disorders as well as an exposition to chemical hepatotoxic substances, or an additional application of potential hepatotoxic drugs. 9 of 14 patients had been treated with propranolol and dihydralazine simultaneously. One female patient showed the typical morphologic pattern of 'dihydralazine-damage' after application of propranolol only. In 3 cases with reexposition of dihydralazine merely one of them developed the typical histological behaviour documented in the literature. Distinct fibrosis of the liver remained in 2 cases. Consequently, to the hitherto existing pathogenetic concept of dihydralazine-caused liver injury as a metabolic-toxic-allergic one, there is to be added the new aspect of summing up of the actions of various additional noxious agents.