Changes in liver biochemical tests at diagnosis and after propylthiouracil therapy for hyperthyroidism

We investigated liver biochemical tests at diagnosis and after a 6-week treatment with propylthiouracil (PTU) in forty-three patients with hyperthyroidism. At diagnosis, 60.5% of the patients had at least one liver biochemical abnormality. Elevation of alkaline phosphatase (ALP), alanine (ALT) and aspartate (AST) aminotransferase, and gamma-glutamyl transpeptidase (GGT) levels were observed in 19 (44.2%). 10 (23.3%), 6 (14%) and 6 (14%) of the patients, respectively. After 6-week treatment with PTU, seven (16.3%) patients developed subclinical hepatotoxicity, as evidenced by elevation of ALT levels. Age, sex, type of goiter (either diffuse or multinodular) and presence or absence of abnormal liver biochemical tests at diagnosis were not significant in determining the possibility of the development of hepatotoxicity. These data suggest that liver biochemical test abnormalities are frequently observed in hyperthyroid. However, presence or absence of these abnormalities do not indicate to the development of subclinical hepatoxicity during 6-week PTU therapy.