Antipsychotic agents used to augment clozapine during long-term inpatient hospitalizations

Literature assessing effective clozapine augmentation strategies is limited. The aim of this retrospective evaluation was to examine antipsychotics used to augment clozapine and assess whether an augmentation antipsychotic would continue at discharge.

Demographic, clinical and pharmacy data were collected retrospectively if patients had received clozapine plus an antipsychotic used for augmentation. The dose of the augmentation agent, length of augmentation therapy, and concomitant medications were collected.

Of the 49 patients (mean age 45.3±12.1 years), 27 (55%) were male. The mean clozapine dose at discharge was 406.1±121.8 mg. When a first generation antipsychotic (FGA) was selected initially to augment clozapine there was a greater likelihood it would be continued until discharge compared to a second generation antipsychotic (SGA) (78 vs. 50%, OR=3.6, 95% CI 1.03-12.6). FGAs (3.2%) compared to SGAs (35%) were less likely to be discontinued due to a documented lack of benefit when first selected to augment clozapine (OR=16.2, 95% CI 2-131.3). Electroconvulsive therapy plus clozapine was found to be beneficial in several patients (n=14) who failed at least 1 augmentation strategy.

This real world data suggests that adding an antipsychotic to clozapine is a reasonable approach to those who do not fully respond to clozapine monotherapy. While comparisons of all agents could not be conducted from this small retrospective study, these data suggest FGAs should be investigated in future studies as potential agents to successfully augment clozapine therapy.