An 8-week, double-blind, randomized, placebo-controlled study of olanzapine long-acting injection in acutely ill patients with schizophrenia.

OBJECTIVE: To examine the efficacy and tolerability of a new injectable formulation of olanzapine, olanzapine long-acting injection (LAI), relative to placebo for treatment of acutely ill patients with schizophrenia. METHOD: Patients with DSM-IV or DSM-IV-TR schizophrenia in this 8-week, double-blind study were randomly assigned to receive 210 mg/2 weeks, 300 mg/2 weeks, or 405 mg/4 weeks of olanzapine LAI or placebo/2 weeks. No oral antipsychotic supplementation was permitted. The primary efficacy measure was mean baseline-to-end point change in Positive and Negative Syndrome Scale (PANSS) total score. The study was conducted from June 2004 to April 2005. RESULTS: Mean baseline-to-end point decreases in PANSS total scores were significantly greater for all olanzapine LAI regimens relative to placebo (all p values < .001). The 300 mg/2 weeks and 405 mg/4 weeks olanzapine LAI groups separated from placebo on the PANSS total at 3 days after starting treatment, and all olanzapine LAI groups separated from placebo by 7 days. Rates of clinical improvement (end point Clinical Global Impressions-Improvement scale score or= 7% of baseline (23.6-35.4% vs. 12.4%, p

D2 receptor occupancy of olanzapine pamoate depot using positron emission tomography: an open-label study in patients with schizophrenia.

A long-acting depot formulation of olanzapine that sustains plasma olanzapine concentrations for over a month after a single injection is currently under development. This multicenter, open-label study explored D(2) receptor occupancy of a fixed dose of olanzapine pamoate (OP) depot given every 4 weeks. Patients (nine male, five female) with schizophrenia or schizoaffective disorder previously stabilized on oral olanzapine were switched to OP depot 300 mg by intramuscular injection every 4 weeks for 6 months. No visitwise within-group significant changes were found in Brief Psychiatric Rating Scale Total or Clinical Global Impressions-Severity of Illness scores, although seven patients received oral olanzapine supplementation during the first four injection cycles. To minimize impact on D(2) occupancy, positron emission tomography (PET) scans were not completed during injection cycles that required supplemental oral olanzapine. Two patients reported transient injection site adverse events, which did not result in discontinuation. The most frequently reported treatment-emergent adverse events were insomnia, aggravated psychosis, and anxiety. Mean striatal D(2) receptor occupancy, as measured by [(11)C]-raclopride PET, was 69% on oral olanzapine (5-20 mg/day) and 50% (trough) on OP depot at steady state. Following an initial decline, occupancy returned to 84% of baseline oral olanzapine occupancy after six injections. Over the study period, D(2) receptor occupancy and plasma olanzapine concentrations were significantly correlated (r=0.76, P

All-cause treatment discontinuation in schizophrenia during treatment with olanzapine relative to other antipsychotics: an integrated analysis.

OBJECTIVES: Treatment continuation, as measured by time to all-cause treatment discontinuation, is a broad measure of overall treatment effectiveness. This integrated analysis compared the likelihood of discontinuation from olanzapine treatment versus other antipsychotics among patients with schizophrenia. METHODS: Clinical trials of all sponsors were included if they met the following criteria: double-blind, randomized, comparative; duration of 12 weeks or longer; no mandatory discontinuation before 12 weeks; and schizophrenia-spectrum disorders; 20 patients or more per treatment. Weighted mean hazard ratios and 95% confidence intervals were calculated from discontinuation time. Meta-analyses were performed for the following comparators that had at least 2 studies: haloperidol (5 studies), risperidone (5 studies), ziprasidone (2 studies), clozapine (3 studies), and perphenazine (2 studies) (13 studies in total; 3 included more than 1 comparator). Only 1 eligible published study was found for fluphenazine, amisulpride, and quetiapine; therefore, meta-analyses could not be performed for these comparators. RESULTS: Significantly (P < 0.05) greater likelihood of discontinuation relative to olanzapine treatment (hazard ratio [95% confidence interval]) was observed for haloperidol (1.4 [1.2-1.7]), risperidone (1.3 [1.1-1.6]), ziprasidone (1.6 [1.4-2.0]), and quetiapine (1.4 [1.1-1.9]), but not clozapine (1.2 [0.9-1.6]), fluphenazine (1.8 [0.8-4.3]), perphenazine (1.3 [0.7-2.1]), or amisulpride (1.1 [0.8-1.6]). CONCLUSIONS: These data suggest that patients with schizophrenia and related disorders may continue olanzapine treatment longer than haloperidol, risperidone, ziprasidone, or quetiapine treatment.

A double-blind, randomized trial to evaluate the pharmacokinetics and tolerability of 30 or 40 mg/d oral olanzapine relative to 20 mg/d oral olanzapine in stable psychiatric subjects.

BACKGROUND: Prescription monitoring in the United States suggests that oral olanzapine is prescribed in doses that exceed the approved range of 5 to 20 mg/d. OBJECTIVE: In this double-blind, randomized study, the pharmacokinetics and tolerability of higher-dose (30 or 40 mg/d) olanzapine were examined relative to the highest approved dose (20 mg/d) among non-treatment-resistant patients with psychiatric illnesses. METHODS: After a 10-day period in which all patients were stabilized on 20 mg/d olanzapine, 37 patients with schizophrenia, schizoaffective disorder, or bipolar I disorder were randomized to receive treatment with olanzapine 20 mg/d for 20 days (group A, n=12), 30 mg/d for 10 days followed by 40 mg/d for 10 days (group B, n=11), or 40 mg/d for 20 days (group C, n=14). On days 10, 20, and 30, blood samples were collected before dosing and at 1, 2, 5, 6, 10, 14, 18, and 24 hours after dosing. Plasma olanzapine concentrations were assayed using high-performance liquid chromatography with electrochemical detection. Tolerability was assessed by spontaneously reported treatment-emergent adverse events; changes from baseline in vital signs, electrocardiograms, and standard laboratory test values; incidences of categorically defined treatment-emergent akathisia and parkinsonism; and 2-hour standard oral glucose tolerance tests. RESULTS: Of the 53 subjects who entered the study, 16 were excluded (7 because entry criteria were not met, 6 because of subject's decision, and 3 for other reasons). Subjects were primarily men (group A, 75%; group B, 55%; group C, 79%), approximately 40 years old (mean [SD] age: group A, 40.6 [8.6]; group B, 37.9 [8.6]; group C, 39.4 [9.2] years), and black (group A, 83%; group B, 55%; group C, 64% [the remainder were white]). Mean (SD) baseline weight was 84.0 (17.5) kg for group A, 82.1 (12.0) kg for group B, and 100.9 (23.3) kg for group C. By day 20, dose-proportional increases were observed in plasma olanzapine Cmax,ss and AUC. Geometric mean (percent coefficient of variation) values for groups A, B, and C at day 20 were as follows: Cmax,ss 57.8 (40.2), 75.6 (86.7), and 94.1 (50.2) ng/mL, respectively; and AUC: 997 (38.5), 1220 (88.0), and 1630 (53.9) ng . h/mL, respectively. The most frequently reported adverse events were weight gain (group A, 2/12 [17%]; group B, 3/11 [27%]; group C, 2/14 [14%]) and sedation (group A, 3/12 [25%]; group B, 2/11 [18%]; group C, 2/14 [14%]). Mean (SD) weight gain from baseline to end point was 3.5 (2.81) kg for group A, 3.0 (3.15) kg for group B, and 3.1 (2.22) kg for group C. Changes in glucose tolerance, vital signs, or laboratory parameters did not appear to be dose dependent. During double-blind therapy, 7 subjects experienced akathisia (spontaneously reported, n=3 [group C]; categorically defined, n=3 [group B]; both, n=1 [group C]). Of the subjects with categorically defined akathisia, 2 had a history of akathisia and the other had a score of 1 (questionable) on the Barnes Akathisia Scale at baseline. No cases of parkinsonism were observed at any time. CONCLUSIONS: Among these subjects with psychiatric illnesses, olanzapine at doses of 30 and 40 mg/d displayed a pharmacokinetic profile consistent with that of 20 mg/d. Higher-dose olanzapine exhibited a tolerance profile similar to that of 20 mg/d; however, akathisia may be more likely to occur at higher doses, particularly in subjects with a history of akathisia.

Cross-sectional comparison of fasting lipids in normoglycemic patients with schizophrenia during chronic treatment with olanzapine, risperidone, or typical antipsychotics.

We compared fasting lipids and other metabolic parameters in 211 normoglycemic patients meeting the DSM-IV diagnosis of schizophrenia or schizoaffective disorder undergoing continuous treatment with olanzapine, risperidone, or typical antipsychotics for at least 1 year. Blood samples were obtained after an 11-hour (+/-1 h) observed fast. Olanzapine-treated patients had significantly higher mean fasting triglyceride levels (2.3 +/- 1.8 mmol/L) than risperidone- (1.7 +/- 0.9 mmol/L, P = 0.022), but not typical antipsychotic-treated patients (1.8 +/- 1 mmol/L). There were no significant differences in total low-density (LDL-C) or high-density lipoprotein cholesterol levels. Apolipoprotein-B and very low density lipoprotein cholesterol levels were significantly higher in the olanzapine- versus risperidone-treated patients, but there were no significant differences between olanzapine- and typical antipsychotic-treated patients. Treatment groups did not differ significantly in LDL particle size, the prevalence of an "atherogenic" lipid profile, or estimated insulin sensitivity. Although interpretation of this study is limited by the cross-sectional study design, it provides additional insight concerning the relationship between antipsychotic use and plasma lipid parameters in this population.

Characteristics of two alternative schizophrenia remission definitions: relationship to clinical and quality of life outcomes.

BACKGROUND: The goal of these secondary analyses of clinical trial data was to characterize clinical outcomes in patients with schizophrenia who met symptom severity or duration thresholds for two alternative definitions of remission, and to explore their relationships to improvement duration and quality of life outcomes. METHODS: Definition 1 used threshold criteria for selected PANSS items sustained over at least 6-months Definition 2 used Brief Psychiatric Rating Scale (BPRS) % change, a threshold score for the Clinical Global Improvement-Severity (CGI-S) maintained for at least 8 weeks, and threshold scores for selected BPRS items. Positive and Negative Symptom Scale (PANSS) and Quality of Life scale (QLS) total scores were pooled from 6 clinical trials. The extent to which the alternative severity thresholds from these two definitions and duration of clinical improvement were associated with different clinical and QLS outcomes was explored. Regression analysis also assessed the relative contribution of each of the components of the two definition severity thresholds to improvements in QLS Total score. RESULTS: Increases in QLS scores were greater for those patients who met either threshold criteria relative to those who met neither (p<.0001). Significantly greater improvements in QLS scores were observed for patients who met either threshold criteria at the 8-, 16- and 24-week visits relative to those who met criteria at weeks 16 and 24, or at week 24 only (p<0.001), as well as for the subset of patients who met threshold criteria at both 24 and 52 weeks relative to those who met criteria at only one of these 2 time points. Only 31% to 47% of patients meeting threshold criteria for either definition at the 8-, 16- or 24-week visits remained in remission at the 52-week visit. Among the severity threshold components analyzed, BPRS total % change from baseline was the strongest predictor of improvement in QLS scores. CONCLUSIONS: Quality of life improved most for patients who achieved severity thresholds associated with either remission criteria and who stayed improved for longer periods. Total BPRS change scores accounted for the greatest percentage of the QLS scores variance. Only a fraction of patients who meet severity criteria for either remission definition early in treatment will remain at that level of improvement within the subsequent 9-12 months.

Is quality of life among minimally symptomatic patients with schizophrenia better following withdrawal or continuation of antipsychotic treatment?

This secondary report from our 52-week, double-blind, relapse prevention trial tested whether stable patients with schizophrenia who were taken off active drug treatment would experience greater improvements in long-term quality of life than those who were continued on antipsychotic treatment. On average, Heinrichs-Carpenter Quality-of-Life Scale total scores improved by 4.3 +/- 10.6 points during treatment with olanzapine (10-20 mg/d; n = 212), but decreased by 7.1 +/- 14.6 points during treatment with placebo (n = 92; P < 0.001). Mean Quality-of-Life Scale total scores worsened in both treatment groups for the relapsing patient subgroup, whereas for nonrelapsing patients, those treated with olanzapine had significantly improved mean Quality-of-Life Scale total scores compared with those given placebo. For a subset of nonrelapsing patients who were considered "nonexacerbating" on the basis of minimal non-clinically relevant increases in psychopathology, Quality-of-Life Scale total mean change was no better (P = 0.066) for those given placebo (2.7 +/- 11.0; n = 40) than those treated with olanzapine (5.7 +/- 8.9; n = 174). Path analysis indicated a direct effect of treatment (approximately 29%) on quality of life that was not accounted for by differential changes in psychopathology. In conclusion, stable patients with schizophrenia who were taken off active drug treatment experienced no greater improvements in long-term quality of life than those who were continued on antipsychotic treatment, even in the absence of psychotic symptoms.

A retrospective comparison of cumulative time spent in remission during treatment with olanzapine or risperidone among patients with schizophrenia.

BACKGROUND: Available studies suggest comparable efficacy of olanzapine and risperidone for the treatment of schizophrenia over the short term. METHOD: This retrospective analysis of data from a 28-week, double-blind, schizophrenia trial compared the cumulative amount of time that patients met severity criteria for remission during olanzapine (10-20 mg/day) or risperidone (4-12 mg/day) treatment. RESULTS: The percentage cumulative time spent in remission was 40% for olanzapine- and 31% for risperidone-treated patients (P = 0.03) using Definition 1 (PANSS items P1, P2, P3, N1, N4, N6, G5, G9 < or = 3), and 18% and 11% (P = 0.01), respectively, using Definition 2 (BPRS Total reduced 50%, BPRS psychosis items < or = 3, CGI-severity < or = 3). CONCLUSION: During 28 weeks of treatment, olanzapine-treated patients spent more cumulative time in remission than risperidone-treated patients.

A double-blind, randomized, placebo-controlled trial of olanzapine in the prevention of psychotic relapse.

Sustained response to antipsychotic therapy is an important outcome measure for patients with psychotic disorders. Placebo control in studies of relapse prevention contributes valuable information yet provokes much debate. This study, using placebo as a control, evaluated olanzapine's efficacy in preventing a psychotic relapse. Participants were stable minimally symptomatic outpatients with schizophrenia or schizoaffective disorder. The study included 4 phases: (1) 4-day to 9-day screening/evaluation (N = 583), (2) 6-week conversion to open-label olanzapine (N = 493; 10-20 mg/d), (3) 8-week stabilization on olanzapine (N = 458; 10-20 mg/d), and (4) 52-week randomized (2:1), double-blind maintenance with olanzapine (N = 224; 10-20 mg/d) or placebo (N = 102). Primary relapse criteria were clinically significant changes in the Brief Psychiatric Rating Scale (BPRS) positive item cluster or rehospitalization due to positive symptoms. Statistical methodology allowed sequential real-time estimation of efficacy across blinded treatment groups and multiple interim analyses, which permitted study termination when efficacy was significantly different between treatments. A significant between-treatment difference emerged 210 days after first patient randomization to double-blind treatment. Thus, 151 (46.3%) of the randomized patients were discontinued early and 34 (10.4%) of the planned patient enrollment were not required. The olanzapine group had a significantly longer time to relapse (P < 0.0001) than the placebo group. The 6-month cumulative estimated relapse rate (Kaplan-Meier) was 5.5% for olanzapine-treated patients versus 55.2% for placebo-treated patients. The design of this study enabled appropriate statistical testing of the primary hypothesis while minimizing exposure of patients to a less effective treatment than olanzapine. In remitted stabilized patients with schizophrenia or schizoaffective disorder, olanzapine demonstrated a positive benefit-to-risk profile in relapse prevention.

A comparison of the efficacy and safety of olanzapine versus haloperidol during transition from intramuscular to oral therapy.

BACKGROUND: Acutely agitated patients with schizophrenia who receive intramuscular (IM) medications typically are switched to oral (PO) antipsychotic maintenance therapy. OBJECTIVE: The goal of this study was to assess the efficacy and safety of olanzapine versus those of haloperidol during transition from IM to PO therapy. We used additional data from a previously reported trial to test the hypothesis that the reduction in agitation achieved by IM olanzapine 10 mg or IM haloperidol 7.5 mg would be maintained following transition to 4 days of PO olanzapine or PO haloperidol (5-20 mg/d for both). We also hypothesized that olanzapine would maintain its more favorable extrapyramidal symptom (EPS) safety profile. METHODS: This was a multinational (hospitals in 13 countries), double-blind, randomized, controlled trial. Acutely agitated inpatients with schizophrenia were treated with 1 to 3 IM injections to olanzapine 10 mg or haloperidol 7.5 mg over 24 hours and were entered into a 4-day PO treatment period with the same medication (5-20 mg/d for both). The primary efficacy measurement was reduction in agitation, as measured by the Positive and Negative Syndrome Scale-Excited Component (PANSS-EC) score. Adverse events and scores on EPS rating scales were assessed. RESULTS: A total of 311 patients (204 men, 107 women; mean [SD] age, 38.2 [11.6] years) were enrolled (131, 126, and 54 patients in the olanzapine, haloperidol, and placebo groups, respectively). In all, 93.1% (122/131) of olanzapine-treated patients and 92.1% (116/126) of haloperidol-treated patients completed the IM period and entered the PO period; 85.5% (112/131) of olanzapine-treated patients and 84.1% (106/126) of haloperidol-treated patients completed the PO period. IM olanzapine and IM haloperidol effectively reduced agitation over 24 hours (mean [SD] PANSS-EC change, -7.1 [4.81 vs -6.7 [4.3], respectively). Reductions in agitation were sustained throughout the PO period with both study drugs (mean [SD] change from PO period baseline, -0.6 [4.8] vs -1.3 [4.4], respectively). During PO treatment, haloperidol-treated patients spontaneously reported significantly more acute dystonia than olanzapine-treated patients (4.3%[5/116] vs 0% [0/122], respectively; P = 0.026) and akathisia (5.2% [6/116] vs 0% [0/122], respectively; P = 0.013). Significantly more haloperidol-treated patients than olanzapine-treated patients met categorical criteria for treatment-emergent akathisia (18.5% [17/92] vs 6.5% [7/107], respectively; P = 0.015). CONCLUSIONS: In the acutely agitated patients with schizophrenia in this study, both IM olanzapine 10 mg and IM haloperidol 7.5 mg effectively reduced agitation over 24 hours. This alleviation of agitation was sustained following transition from IM therapy to 4 days of PO treatment (5-20 mg/d for both). During the 4 days of PO treatment, olanzapine-treated patients did not spontaneously report any incidences of acute dystonia, and olanzapine had a superior EPS safety profile to that of haloperidol. The combination of IM and PO olanzapine may help improve the treatment of acutely agitated patients with schizophrenia.

Effects of intramuscular olanzapine vs. haloperidol and placebo on QTc intervals in acutely agitated patients.

Prolongation of the QTc interval has been reported during treatment with oral antipsychotic agents and may be more pronounced during parenteral administration. Pooled QTc interval data from acutely agitated patients across four double-blind trials were compared. Databases included: placebo-controlled [two schizophrenia, one bipolar mania trials (n=565)]; haloperidol-controlled [two schizophrenia trials (n=482)]; geriatric placebo-controlled [1 dementia trial (n=204)]. Patients received 1-3 injections of intramuscular (IM) olanzapine (2.5-10 mg/injection), IM haloperidol (7.5 mg/injection), or IM placebo. At 2 and 24 h after IM olanzapine treatment, the mean QTc interval decreased approximately 3 ms from baseline in the placebo- and haloperidol-controlled databases. When there was a statistically significant difference between IM olanzapine and IM placebo, QTc intervals decreased during treatment with IM olanzapine and increased with IM placebo. The incidences of prolonged (endpoint >/=99th percentile of healthy adults or >/=500 ms) or lengthened (increase >/=60 ms) QTc intervals during treatment with IM olanzapine (<3% placebo- and haloperidol-controlled databases, <12% geriatric placebo-controlled database) were never significantly greater than with comparators. These data suggest that IM olanzapine has a favorable QTc interval profile in acutely agitated patients with schizophrenia, bipolar mania, or dementia.

Intramuscular olanzapine and intramuscular haloperidol in acute schizophrenia: antipsychotic efficacy and extrapyramidal safety during the first 24 hours of treatment.

OBJECTIVE: To determine the antipsychotic efficacy and extrapyramidal safety of intramuscular (i.m.) olanzapine and i.m. haloperidol during the first 24 hours of treatment of acute schizophrenia. METHOD: Patients (n = 311) with acute schizophrenia were randomly allocated (2:2:1) to receive i.m. olanzapine (10.0 mg, n = 131), i.m. haloperidol (7.5 mg, n = 126), or i.m. placebo (n = 54). RESULTS: After the first injection, i.m. olanzapine was comparable to i.m. haloperidol and superior to i.m. placebo for reducing mean change scores from baseline on the Brief Psychiatric Rating Scale (BRPS) Positive at 2 hours (-2.9 olanzapine, -2.7 haloperidol, and -1.5 placebo) and 24 hours (-2.8 olanzapine, -3.2 haloperidol, and -1.3 placebo); the BPRS Total at 2 hours (-14.2 olanzapine,-13.1 haloperidol, and -7.1 placebo) and 24 hours (-12.8 olanzapine, -12.9 haloperidol, and -6.2 placebo); and the Clinical Global Impressions (CGI) scale at 24 hours (-0.5 olanzapine, -0.5 haloperidol, and -0.1 placebo). Patients treated with i.m. olanzapine had significantly fewer incidences of treatment-emergent parkinsonism (4.3% olanzapine vs 13.3% haloperidol, P = 0.036), but not akathisia (1.1% olanzapine vs 6.5% haloperidol, P = 0.065), than did patients treated with i.m. haloperidol; they also required significantly less anticholinergic treatment (4.6% olanzapine vs 20.6% haloperidol, P < 0.001). Mean extrapyramidal symptoms (EPS) safety scores improved significantly from baseline during i.m. olanzapine treatment, compared with a general worsening during i.m. haloperidol treatment (Simpson-Angus Scale total score mean change: -0.61 olanzapine vs 0.70 haloperidol; P < 0.001; Barnes Akathisia Scale global score mean change: -0.27 olanzapine vs 0.01 haloperidol; P < 0.05). CONCLUSION: I.m. olanzapine was comparable to i.m. haloperidol for reducing the symptoms of acute schizophrenia during the first 24 hours of treatment, the efficacy of both being evident within 2 hours after the first injection. In general, more EPS were observed during treatment with i.m. haloperidol than with i.m. olanzapine.

Dissolution profile, tolerability, and acceptability of the orally disintegrating olanzapine tablet in patients with schizophrenia.

OBJECTIVE: This pilot study investigates the dissolution profile, tolerability, and acceptability of an orally disintegrating olanzapine tablet in patients with schizophrenia. METHOD: Eleven patients with schizophrenia stabilized on oral olanzapine (mean dosage 12.7 mg daily [SD5.2]) were given an orally disintegrating olanzapine tablet, rather than their usual tablet, daily for 7 days. At each visit, visual assessments were made for elapsed time to initial disintegration (every 15 seconds) and complete disintegration (every 1 minute). At the end of the study, patients completed a drug-acceptance questionnaire. RESULTS: The mean time to initial disintegration was 15.78 seconds, and mean time to complete disintegration was 0.97 minutes. All patients found the orally disintegrating tablet acceptable and expressed positive comments. Nonserious clinically significant adverse events, asthenia, purpuric rash, headache, depression, and insomnia (preexisting, except for asthenia and insomnia) were reported in 3 patients. CONCLUSION: The orally disintegrating olanzapine tablet disintegrates rapidly and is a well-tolerated and acceptable alternative to standard olanzapine tablets in patients with schizophrenia.

A double-blind, placebo-controlled dose-response comparison of intramuscular olanzapine and haloperidol in the treatment of acute agitation in schizophrenia.

BACKGROUND: An intramuscular (IM) formulation of olanzapine has been developed because there are no rapid-acting IM atypical antipsychotic drugs currently available in the United States for treating acute agitation in patients with schizophrenia. METHODS: Recently hospitalized acutely agitated patients with schizophrenia (N = 270) were randomized to receive 1 to 3 IM injections of olanzapine (2.5, 5.0, 7.5, or 10.0 mg), haloperidol (7.5 mg), or placebo within 24 hours. A dose-response relationship for IM olanzapine in the reduction of agitation was assessed by measuring the reduction in Positive and Negative Syndrome Scale Excited Component (PANSS-EC) scores 2 hours after the first injection. Safety was assessed by recording adverse events and with extrapyramidal symptom scales and electrocardiograms at 24 hours after the first injection. RESULTS: Olanzapine exhibited a dose-response relationship for reduction in agitation (F(1,179)= 14.4; P<.001). Mean PANSS-EC reductions 2 hours after the first injection of olanzapine (2.5 mg = -5.5; 5.0 mg = -8.1; 7.5 mg = -8.7; 10.0 mg = -9.4) were superior to those with placebo (-2.9; P =.01 vs olanzapine at 2.5 mg; P<.001 for each other olanzapine dose) but not with haloperidol (-7.5). A dose of 5.0, 7.5, or 10.0 mg of olanzapine caused a greater reduction in agitation than placebo 30 minutes after the first injection. There were no differences between treatment groups for hypotension, the most frequently reported adverse event, or for clinically relevant changes in the QTc interval. There was a greater incidence of treatment-emergent parkinsonism during treatment with IM haloperidol (16.7%) than with 2.5 (P =.03), 5.0 (P =.03), or 7.5 mg (P =.01) of IM olanzapine (0%) or with placebo (0%) (P =.01). CONCLUSIONS: Intramuscular olanzapine at a dose of 2.5 to 10.0 mg per injection exhibits a dose-response relationship in the rapid treatment of acute agitation in patients with schizophrenia and demonstrates a favorable safety profile.