Naturalistic observation on the hepatic enzyme changes in patients treated with either risperidone or olanzapine alone

This retrospective study aimed to compare differences in hepatic enzyme elevation during treatment with either risperidone or olanzapine alone in patients with psychotic disorders. The charts were reviewed for six hundred and sixty-seven (667) inpatients with psychotic disorders who were treated with either risperidone (n = 289) or olanzapine (n = 145) alone at a university-affiliated hospital between 1998 and 2002. Frequencies of elevation greater than the reference level in any enzyme among aspartate amino-transferase (AST), alanine aminotransferase (ALT) and alkaline phosphotase (ALP) were higher in the olanzapine-treated group (26.9%) than in the risperidone-treated group (14.2%) [odds ratio (OR) = 2.225, 95% confidence interval (Cl) = 1.362-3.638, P = 0.002]. Frequencies of elevation greater than the reference level in ALT were higher in the olanzapine-treated group than in the risperidone-treated group (OR = 2.182, P = 0.004), as were frequencies with two-fold (OR = 3.064, P = 0.017) and three-fold (OR = 2.883, P = 0.039) elevation. Recovery time was longer in the olanzapine-treated group than in the risperidone-treated group (P = 0.0059), as was latency time (P = 0.0044). These results suggest that there are potential differences in antipsychotic-associated hepatic enzyme alterations between risperidone and olanzapine treatment. Controlled, prospective studies should be conducted to identify the risk factors associated with an alteration in hepatic enzymes related to treatment with risperidone and olanzapine.