Safety and Tolerability of Once-daily Extended Release Quetiapine Fumarate in Acute Schizophrenia: Pooled Data from Randomised, Double-blind, Placebo-controlled Studies

Introduction: Extended release quetiapine fumarate (quetiapine XR) is a new formulation that allows once-daily dosing and a titration regimen that is simpler than that of immediate release quetiapine (quetiapine IR) and may potentially increase patients' adherence to their prescribed medication.

Methods: The tolerability of quetiapine XR was examined in an analysis of pooled data from three Phase III, double-blind, placebo-controlled, randomised studies with quetiapine IR as a reference treatment.

Results: The overall incidence of adverse events (AEs) was similar for quetiapine XR (69.5%) and quetiapine IR (72.5%). Most AEs were mild to moderate in severity and in line with those observed with quetiapine IR. The more rapid dose titration of quetiapine XR did not produce any new safety concerns and was as well tolerated as the regimen for quetiapine IR.

Conclusions: The results of this pooled analysis show that quetiapine XR administered once daily is generally as well tolerated as quetiapine IR given twice daily. These data, together with the simpler dose-titration of quetiapine XR that allowed therapeutically effective doses to be reached by Day 2, suggest that this formulation potentially may improve adherence in patients with schizophrenia.