In this study, 28 patients suffering from hyperlipidemia who were on simvastatin ,were included for determination serum guanase activity. Guanase activity was observed at high level in those patients (n = 16) who were on prolonged treatment with simvastatin (more than 30 days) but its activity remained within normal when simvastation was administrated at interrupted intervals . The results were compared with two control groups the first (n=10) with hyperlipidemia but with no simvastatin and the second (n=10) was normal individuals with no history of hyperlipidemia. However, guanase activity was found to be normal in both control groups .
Besides, this study was found that alkaline phosphatase was also increased in some patients , However , guanase activity was observed earlier than alkaline phosphatase which have suggested that simvastatine could cause liver injuries when used for a long time . This study is the first study conducted to predict liver injuries as a result of simvastatin through guanase elevation .