Pharmacokinetic, bioavailability, & bioequivalenceOriginal researchSelf-Reported Sedation Profile of Quetiapine Extended-Release and Quetiapine Immediate-Release During 6-Day Initial Dose Escalation in Bipolar Depression: A Multicenter, Randomized, Double

abstractBackgroundA human-volunteer study reported lower sedation intensity during escalation of the extended-release formulation of quetiapine fumarate (quetiapine XR) than the immediate-release (IR) formulation.ObjectiveTo test the hypothesis that the profile of initial tolerability, including sedation, differs between the extended-release (XR) and immediate-release (IR) formulations of quetiapine in patients with bipolar depression.MethodsIn a randomized, double-blind, double-dummy, parallel-group, Phase IV study, male and female inpatients aged 18 to 50 years with a Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition, Text Revision) diagnosis of bipolar I or II depression were randomized after washout to receive placebo on day 1 and quetiapine XR or IR at escalating doses of 50, 100, 200, 300, and 300 mg once daily on the evenings of days 2 to 6, with hospital discharge on day 7. Sedation intensity was assessed by a self-reported modified Bond-Lader visual analog scale (VAS) score.ResultsOf 139 randomized patients, 134 completed the study. Mean patient age was 39.0 years; mean weight, 91.3 kg; and mean body mass index (calculated as weight in kilograms divided by height in meters squared), 31.0. Sedation intensity 1 hour after administration of the 50-mg dose (the primary study measure) was statistically significantly lower with quetiapine XR versus IR (mean [SD] VAS score: 33.4 [26.92] vs 44.0 [31.76]; least squares mean difference: 12.55, P = 0.009; modified intention-to-treat population). Sedation intensity was found in secondary analyses to be significantly lower with quetiapine XR than with quetiapine IR 1, 2, and 3 hours after each dose on days 2 to 6 (P ≤ 0.05), with similar sedation intensity between the treatment groups 4 to 14 hours postdose. Rates of treatment-related adverse events were 47.1% with quetiapine XR versus 59.4% with quetiapine IR. Three serious adverse events (4.3%) occurred in the quetiapine XR group. Adverse events led to study discontinuation in 1 patient (1.4%) in the quetiapine XR group and in 2 patients (2.9%) in the IR group.ConclusionsDuring the initial dose-escalation period studied, patients with bipolar depression reported statistically significantly lower sedation intensity in the 1 to 3 hours after taking quetiapine XR compared with the IR formulation. Overall tolerability for both formulations was consistent with the known profile of quetiapine. ClinicalTrials.gov identifier: NCT00926393.