Bruce J. Kinon

Mechanisms of action of atypical antipsychotic drugs: a critical analysis

Various criteria used to define atypical antipsychotic drugs include: 1) decrease, or absence, of the capacity to cause acute extrapyramidal motor side effects (acute EPSE) and tardive dyskinesia (TD); 2) increased therapeutic efficacy reflected by improvement in positive, negative, or cognitive symptoms; 3) and a decrease, or absence, of the capacity to increase prolactin levels. The pharmacologic basis of atypical antipsychotic drug activity has been the target of intensive study since the significance of clozapine was first appreciated. Three notions have been utilized conceptually to explain the distinction between atypical versus typical antipsychotic drugs: 1) dose-response separation between particular pharmacologic functions; 2) anatomic specificity of particular pharmacologic activities; 3) neurotransmitter receptor interactions and pharmacodynamics. These conceptual bases are not mutually exclusive, and the demonstration of limbic versus extrapyramidal motor functional selectivity is apparent within each arbitrary theoretical base. This review discusses salient distinctions predominantly between prototypic atypical and typical antipsychotic drugs such as clozapine and haloperidol, respectively. In addition, areas of common function between atypical and typical antipsychotic drug action may also be crucial to our identification of pathophysiological foci of the different dimensions of schizophrenia, including positive symptoms, negative symptoms, and neurocognitive deficits.

A multicenter, inpatient, phase 2, double-blind, placebo-controlled dose-ranging study of LY2140023 monohydrate in patients with DSM-IV schizophrenia

The primary objective of this study was to test the hypothesis that 1 or more dose levels of LY2140023 monohydrate, an oral prodrug of the potent metabotropic glutamate (mGlu) 2/3 receptor agonist LY404039, given to patients with schizophrenia for 4 weeks would demonstrate significantly greater efficacy than placebo. The HBBI study was a multicenter, randomized, double-blind, parallel, placebo- and active-controlled trial. Male and female patients aged 18 to 65 years who met the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria for schizophrenia were randomized in a 2:2:2:2:2:1 ratio to receive 5-, 20-, 40-, or 80-mg LY2140023 monohydrate twice daily, placebo twice daily, or placebo (am) and 15 mg of olanzapine (pm) daily. Efficacy was defined as the change from baseline on the Positive and Negative Syndrome Scale (PANSS) total score assessed at 4 weeks. The primary analysis did not show that any of the 4 LY2140023 monohydrate doses were more efficacious than placebo as measured by the PANSS total score. Similarly, olanzapine did not significantly separate from placebo. A higher-than-anticipated treatment effect (14.6-point improvement) in the placebo group was observed on PANSS total score. LY2140023 monohydrate was generally well tolerated, although 4 patients reported the serious adverse event of convulsion. LY2140023 monohydrate-treated patients showed little change in dopamine-related adverse events and weight. The results of the HBBI study are considered to be inconclusive because LY2140023 monohydrate and the active control olanzapine did not separate from placebo in the treatment of patients with acutely exacerbated schizophrenia. Additional efficacy, safety, and tolerability testing are needed.

Association between early and rapid weight gain and change in weight over one year of olanzapine therapy in patients with schizophrenia and related disorders.

Abstract: Weight gain is an important issue in the use of atypical antipsychotics, including olanzapine. A retrospective analysis of patterns of weight gain and possible covariates was performed for 1191 patients diagnosed with schizophrenia or schizoaffective disorder who were treated with olanzapine for up to 52 weeks. Patients were dichotomized into 2 main groups according to the percentage of body weight gained during the first 6 weeks of treatment with olanzapine: (1) patients who gained ≥7% of their body weight (Rapid Weight Gain Group [RWG]), and (2) patients who lost weight, gained no weight, or gained <7% of their body weight (Nonrapid Weight Gain Group [NRWG]). Results demonstrated that approximately 15% of the patient population showed rapid increases in weight (RWG group), whereas 85% of patients gained weight more slowly or not at all (NRWG group). Patients in the RWG group gained an average of 4% of their body weight (approximately 4-7 lb) within the first 2 weeks of treatment with olanzapine. Furthermore, patients in the RWG group were younger, had a lower baseline body mass index, were more likely to report an increase in appetite, and showed a more robust clinical response compared with patients in the NRWG group. Over the course of 52 weeks, patients in the RWG group gained significantly more weight and reached a higher plateau for mean weight increase at 38 weeks compared with the mean increase observed for patients in the NRWG group. By measuring the weight of patients during the first few weeks of olanzapine treatment and by assessing changes in appetite, clinicians may be able to identify those patients at risk for substantial weight gain.

A 24-week randomized study of olanzapine versus ziprasidone in the treatment of schizophrenia or schizoaffective disorder in patients with prominent depressive symptoms

Objective: The objective of this study is to compare olanzapine with ziprasidone therapy in patients with schizophrenia or schizoaffective disorder and experiencing depressive symptoms. Methods: This randomized, double-blind, 24-week, fixed-dose study compared olanzapine (n = 202) and ziprasidone (n = 192) for patients with schizophrenia or schizoaffective disorder and experiencing prominent depressive symptoms. Outcome measures included change in Calgary Depression Scale for Schizophrenia (CDSS) score from baseline to 8 weeks (primary outcome) and changes in CDSS, Montgomery-Åsberg Depression Rating Scales, Positive and Negative Syndrome Scale, and Global Assessment of Functioning (GAF) scores for 24 weeks. Statistical analyses included mixed-effects model repeated measures (primary analysis) and change from baseline to last observation carried forward (LOCF). Results: At baseline, patients had moderate depressive symptoms (mean Montgomery-Åsberg Depression Rating Scales total score, 27.3). For 8 weeks, patients treated with olanzapine or ziprasidone had significant improvements on CDSS. Treatment group differences were not statistically significant (P = 0.493, mixed-effects model repeated measures; P = 0.497, LOCF). For 24 weeks, olanzapine-treated patients showed significantly greater improvements in depressive symptoms (results varied by depression measure and statistical approach) and GAF (P < 0.017, LOCF). A significantly higher proportion of olanzapine-treated patients completed the study (44.6% vs 29.7%; P = 0.003) and remained longer on medication (median, 163 vs 73 days, P < 0.001), compared with ziprasidone-treated patients. Olanzapine-treated patients experienced significantly (P < 0.05) greater increases in triglycerides, HgbA1c, and weight. Conclusions: For 24 weeks, olanzapine-treated patients had greater and more sustained participation in treatment, during which time significantly greater improvements were observed in depressive symptoms and GAF scores, along with increases in weight and certain metabolic parameters as compared with ziprasidone-treated patients.

Effectiveness of rapid initial dose escalation of up to forty milligrams per day of oral olanzapine in acute agitation.

Background Patients experiencing an acute decompensation of schizophrenia or bipolar disorder often present in an agitated state. Agitation presents a barrier to therapy, interrupting the typical physician-patient alliance and creating a disruptive, even hazardous, environment. Rapid assessment and effective treatment are necessary to manage agitation and, potentially, to shorten the time to recovery. Methods One hundred forty-eight acutely agitated patients received either: rapid initial dose escalation (RIDE) in which up to 40 mg of oral olanzapine was allowed on days 1 and 2, up to 30 mg on days 3 and 4, and 5 to 20 mg thereafter; or usual clinical practice (UCP) in which patients received 10 mg/d olanzapine plus up to 4 mg lorazepam on days 1 and 2, up to 2 mg on days 3 and 4, and olanzapine 5 to 20 mg/d thereafter. The Positive and Negative Syndrome Scale-Excited Component (PANSS-EC: poor impulse control, tension, hostility, uncooperativeness, and excitement) measured at 24 hours was the primary measure. Secondary assessments of agitation and safety were also performed. Results Agitation improved significantly from baseline for both treatment groups; however, improvement with the RIDE strategy was superior to UCP. The RIDE group improvement was superior on the primary efficacy measure (PANSS-Excited) at 24 hours; it was superior on all agitation measures at the end of double-blind treatment. Both treatments were well tolerated, with no clinically significant differences in safety measures. Treatment was not limited by oversedation and attention improved from baseline in both groups. Conclusions This study demonstrates the value of olanzapine in the treatment of acutely agitated patients. A new approach to olanzapine dosing that expands the initial dose range up to 40 mg/d may offer superior efficacy in rapidly and effectively controlling the symptoms of agitation.

Randomized, double-blind 6-month comparison of olanzapine and quetiapine in patients with schizophrenia or schizoaffective disorder with prominent negative symptoms and poor functioning.

Abstract: This study compared the effects of olanzapine (OLZ) with those of quetiapine (QUE) for improving negative symptoms in patients diagnosed with schizophrenia or schizoaffective disorder who had prominent negative symptoms and marked deficits in social or occupational functioning. In this 6-month, multicenter, double-blind clinical trial, patients were randomized to treatment with OLZ (n = 171, 10-20 mg/d) or QUE (n = 175, 300-700 mg/d). Patients were treated at community mental health centers and assigned case managers who developed individualized psychosocial treatment plans. The primary efficacy measure was the reduction in negative symptoms using the Scale for the Assessment of Negative Symptoms. Secondary measures assessed changes in functioning, psychopathology, and treatment tolerability. Treatment with OLZ or QUE led to a significant reduction in negative symptoms, with no between-group difference (P = 0.09). Both treatment groups also showed significant improvement on most efficacy measures. Olanzapine-treated patients showed significantly greater improvement on positive symptoms and on several measures of functioning including Global Assessment of Functioning Scale, Quality of Life Instrumental Role domain, and level of effort in psychosocial or occupational rehabilitation programs. Significantly more OLZ-treated patients completed the study (52.6% OLZ, 37.7% QUE, P = 0.007). Treatment differences in safety were relatively small and not thought to be clinically relevant. Patients with schizophrenia who manifest prominent negative symptoms and marked functional deficits demonstrated significant improvement in negative symptoms after treatment with OLZ or QUE. Greater improvement in positive symptoms and a greater study completion rate may hold relevance to enhanced functional outcomes observed after OLZ therapy.

A Prospective Study of Tardive Dyskinesia Development: Preliminary Results

Preliminary findings from a prospective study of tardive dyskinesia (TD) development in a population of psychiatric patients suggest a TD incidence of 12% after 4 years of cumulative neuroleptic exposure. No cases of abnormal involuntary movements that might be mistaken for TD have been found in patients with no history of neuroleptic exposure. Early findings with regard to risk factors are discussed.

Prevalence of abnormal involuntary movements (“spontaneous dyskinesias”) in the normal elderly

Advancing age has been associated with increased prevalence of abnormal involuntary movements in neuroleptic-treated patients. In order to investigate the possibility that the aging process itself might produce involuntary movements clinically indistinguishable from tardive dyskinesia, a group of healthy elderly volunteers were systematically examined. A 4% prevalence rate of mild involuntary movements was found, suggesting that the aging process itself is not likely to produce dyskinesias without other contributing factors coming into play.

Dose Response and Atypical Antipsychotics in Schizophrenia

Based on information from clinical trials, both the efficacy and adverse effects of conventional antipsychotics in the treatment of schizophrenia are dose related. The overlapping nature of these dose-response profiles limits the use of these agents. Atypical antipsychotics provide greater relief across the comorbid symptom domains of schizophrenia, but dose-response studies and clinical experience have revealed that some of these drugs also have dose limitations. This article reviews the dose-response relationships of the atypical antipsychotics as presented predominantly in pivotal, randomised studies (double-blind and otherwise).Limited data indicate that clozapine shows dose-related efficacy up to 600 mg/ day in patients with treatment-resistant schizophrenia. However, higher dosages of clozapine may be associated with the risk of seizures. Risperidone demonstrates dose-related adverse events that compromise efficacy. The dose-response relationships for ziprasidone, quetiapine and aripiprazole are less well established. The efficacy of olanzapine appears to be dose related within the recommended dosage range of 10–20 mg/day, but clinical trials that have explored higher dosages suggest improved efficacy. Furthermore, the higher doses are not associated with a significantly increased incidence of adverse events.Further studies are clearly needed to fully characterise the dose-response relationships of atypical antipsychotics.

Olanzapine versus aripiprazole for the treatment of agitation in acutely ill patients with schizophrenia.

Rapid control of agitation is of critical importance in the treatment of acutely ill patients with schizophrenia. Both olanzapine and aripiprazole have been shown to be safe and effective in this setting, with each having somewhat different receptor binding affinity profiles. This 5-day, randomized, double-blind trial evaluated relative improvements in agitation in hospitalized patients who received orally dosed olanzapine (n = 306, 20 mg/d) or aripiprazole (n = 298, 15 mg/d, increasing to 30 mg/d as needed). Lorazepam was also given as needed (total dose, ≤4 mg/d) but not in place of a study drug dose increase. The primary efficacy measure was daily mean change from baseline in Positive and Negative Syndrome Scale-Excited Component (PANSS-EC) score. Secondary measures of positive symptoms and safety were also assessed. Significant improvements from baseline in PANSS-EC and secondary efficacy measures were seen for both olanzapine and aripiprazole (P < 0.001),with no between-group differences. A greater proportion of aripiprazole-treated patients received lorazepam at each visit compared with olanzapine-treated patients, but this difference was significant only at visit 5 (41.2% vs 31.0%, P = 0.033). Fasting glucose and triglycerides increased more significantly in olanzapine-treated patients (P = 0.030 and P < 0.001, respectively). Prolactin increased in the olanzapine group and decreased in the aripiprazole group with a significant between-group difference (P < 0.001). During the first 5 days of randomized treatment, olanzapine and aripiprazole displayed similar efficacy profiles for treating agitation associated with schizophrenia. Aripiprazole-treated patients had smaller increases in glucose and lipids, but no difference was observed between treatments in the proportion of patients experiencing categorical shifts in these measures.