Increased alanine transaminase activity associated with tetracycline administration in a cat

Administration of tetracycline was believed to be associated with an adverse drug reaction in a cat. Clinical signs consisted of anorexia, ptyalism, and signs of depression. The most noticeable biochemical abnormality was a markedly high serum alanine transaminase activity. Treatment consisted of vitamin E and selenium injections and feeding via a gastrostomy tube. Abnormalities noticed on histologic examination of hepatic tissue were centrilobular fibrosis, mild diffuse cholangiohepatitis, and mild hepatic lipidosis. The lipidosis was believed to have resulted from tetracycline administration, whereas the more chronic lesions (hepatic fibrosis and mild cholangiohepatitis) were believed to have resulted from preexisting, subclinical hepatic disease. Because serum alanine transaminase activity returned to reference ranges and the anorexia and ptyalism resolved with cessation of tetracycline administration, these abnormalities were believed to have represented an adverse drug reaction. Treatment of the cat with vitamin E and selenium was instituted on the basis of reported preventive and therapeutic effects in albino rats with tetracycline-induced hepatic lesions. Whether these compounds had any role in accelerating clinical recovery in this cat is uncertain.