[Optimizing the antipsychotic potency of olanzapine by augmentation--a critical review]

Up to 40 % of patients with schizophrenic psychosis suffer from symptoms that are resistant to monotherapy with antipsychotic drugs. As a consequence, combined approaches are often used, especially based on clozapine and olanzapine. This review aims to provide a critical overview on olanzapine-augmentations.

A systematic database search including generic and trade names of antipsychotic substances as well as general items such as "augmentation" and "combination" was performed in Medline and BIOSIS (OVID) until May 2005.

Amongst a number of 16 reports dealing with 9 different antipsychotic augmentation strategies (85 patients) only sulpiride was tested in a randomized manner. A significant part of the treatments achieved favourable results. In contrast, augmentations of olanzapine with antidepressants or mood stabilizers were evaluated in well-designed clinical trials (9 strategies, 10 publications, 837 patients). Improvements of positive and/or negative symptoms as well as depressed mood were reported.

The empirical basis to combine olanzapine with antipsychotic substances has to be improved in order to evaluate benefits and risks. Augmentations with mood stabilizers were successful, for example on hostility, showing that randomized and placebo-controlled trials are feasible.