A history of antipsychotic drug development

Long-acting injectable formulations of antipsychotic drugs for the treatment of schizophrenia

Antipsychotic drugs have been used to treat patients with schizophrenia and other psychotic disorders. Long-acting injectable antipsychotic drugs are useful for improving medication compliance with a better therapeutic option to treat patients who lack insight or adhere poorly to oral medication. Several long-acting injectable antipsychotic drugs are clinically available. Haloperidol decanoate and fluphenazine decanoate are first-generation depot drugs, but the use of these medicines has declined since the advent of second-generation depot agents, such as long-acting risperidone, paliperidone palmitate, and olanzapine pamoate. The second-generation depot drugs are better tolerated and have fewer adverse neurological side effects. Long-acting injectable risperidone, the first depot formulation of an atypical antipsychotic drug, was prepared by encapsulating risperidone into biodegradable microspheres. Paliperidone palmitate is an aqueous suspension of nanocrystal molecules, and olanzapine pamoate is a microcrystalline salt of olanzapine and pamoic acid suspended in aqueous solution. This review summarizes the characteristics and recent research of formulations of each long-acting injectable antipsychotic drug.

Trends in scientific literature on atypical antipsychotics in South Korea: a bibliometric study

OBJECTIVE

We have carried out a bibliometric study on the scientific publications in relation to atypical or second-generation antipsychotic drugs (SGAs) in South Korea.

METHODS

With the EMBASE and MEDLINE databases, we selected those publications made in South Korea whose title included the descriptors atypic(*) (atypical(*)) antipsychotic(*), second-generation antipsychotic(*), clozapine, risperidone, olanzapine, ziprasidone, quetiapine, sertindole, aripiprazole, paliperidone, amisulpride, zotepine, asenapine, iloperidone, lurasidone, perospirone and blonanserin. We applied some bibliometric indicators of paper production and dispersion with Price's law and Bradford's law, respectively. We also calculated the participation index (PI) of the different countries, and correlated the bibliometric data with some social and health data from Korea (such as total per capita expenditure on health and gross domestic expenditure on research and development).

RESULTS

We collected 326 original papers published between 1993 and 2011. Our results state fulfilment of fulfilled Price's law, with scientific production on SGAs showing exponential growth (correlation coefficient r=0.8978, as against an r=0.8149 after linear adjustment). The most widely studied drugs were risperidone (91 papers), aripiprazole (77), olanzapine (53), and clozapine (43). Division into Bradford zones yielded a nucleus occupied by the Progress in Neuro-Psychopharmacology and Biological Psychiatry (36 articles). A total of 86 different journals were published, with 4 of the first 10 used journals having an impact factor being greater than 4.

CONCLUSION

The publications on SGAs in South Korea have undergone exponential growth over the studied period, without evidence of reaching a saturation point.

Drug treatment developments in schizophrenia and bipolar mania: latest evidence and clinical usefulness

Schizophrenia and bipolar disorder are often highly debilitating with chronic courses, and psychotropic drugs represent cornerstones in the treatment. The primary aim of the review was to summarize the latest evidence with regards to the efficacy and effectiveness of drug treatment of schizophrenia and the manic phases of bipolar disorder. Schizophrenia systematic reviews conclude that antipsychotic drugs are effective in treating overall symptoms of psychosis and in preventing relapse. Some of the newer agents, the second-generation antipsychotics (SGAs), have demonstrated superiority compared with the older first-generation drugs and other SGAs but side-effect differences among the drugs are of a greater magnitude than effect differences. The pragmatic randomized trials of effectiveness have shown a longer time until treatment discontinuation for olanzapine compared with other antipsychotics. Cohort studies have found superiority for the long-acting injection formulations compared with the oral formulations of the drugs, and lower total mortality risk in users of antipsychotics compared with non-users. In bipolar mania SGAs have shown superior antimanic efficacy compared with other mood-stabilizing drugs. In conclusion antipsychotics, in particular some of the SGAs, seem to be drugs of first choice for both schizophrenia and bipolar mania. This perspective review focused on mean effects but the group means may not always be particularly useful as schizophrenia and bipolar mania are biologically heterogeneous disorders with large inter-individual variations in drug response and tolerance. In patients with a prior drug history the different pharmacological and clinical profiles may be exploited in subsequent choices of drugs.

Age-associated decrease in serum glial cell line-derived neurotrophic factor levels in patients with major depressive disorder

BACKGROUND

Many studies have supported the role of neurotrophic hypothesis in the pathophysiology of mood disorders. This study examined serum levels of glial cell line-derived neurotrophic factor (GDNF), one of the neurotrophic factors, in patients with major depressive disorder (MDD) at different disease states.

METHODS

The serum GDNF levels were measured in 55 patients with MDD (29 severe patients and 26 remitted patients) and 35 healthy controls by ELISA method. Severity of depressive symptoms was assessed using the 17-item Hamilton Rating Scale of Depression (HAM-D) (HAM-D >/= 19 for severe MDD, HAM-D </= 7 for remitted MDD).

RESULTS

MDD patients were found to have significantly lower serum GDNF levels than healthy controls (p<0.001). This decrease was significant in older-aged (p=0.003) and middle-aged (p=0.026) groups, but not in the younger-aged group. We found no difference in GDNF level between severe and remitted MDD patients.

CONCLUSIONS

In spite of some limitations, our results indicate an age-associated reduction in serum GDNF levels in patients with MDD, further supporting the role of the neurotrophic factor as a disease marker and a new target for developing antidepressant treatment.

Intervention, causal reasoning, and the neurobiology of mental disorders: Pharmacological drugs as experimental instruments

In psychiatry, pharmacological drugs play an important experimental role in attempts to identify the neurobiological causes of mental disorders. Besides being developed in applied contexts as potential treatments for patients with mental disorders, pharmacological drugs play a crucial role in research contexts as experimental instruments that facilitate the formulation and revision of neurobiological theories of psychopathology. This paper examines the various epistemic functions that pharmacological drugs serve in the discovery, refinement, testing, and elaboration of neurobiological theories of mental disorders. I articulate this thesis with reference to the history of antipsychotic drugs and the evolution of the dopamine hypothesis of schizophrenia in the second half of the twentieth century. I argue that interventions with psychiatric patients through the medium of antipsychotic drugs provide researchers with information and evidence about the neurobiological causes of schizophrenia. This analysis highlights the importance of pharmacological drugs as research tools in the generation of psychiatric knowledge and the dynamic relationship between practical and theoretical contexts in psychiatry.

Delivery systems and dosing for antipsychotics

Schizophrenia is a devastating illness, affecting approximately 1-2 % of the world population. Age of onset is generally between 20 and 30 years of age with a chronic, unremitting course for the duration of the patient's life. Although schizophrenia is among the most severe and debilitating illnesses known to medicine, its treatment has remained virtually unchanged for over 50 years. This chapter covers several major concepts in experimental drug development and delivery: (1) the concept of "typical" vs. "atypical" classifications for antipsychotic drugs as it relates to dosing; (2) the development of depot formulations for improved medication adherence; and (3) several promising areas for future therapeutic advances related to the methods and duration of drug administration. These areas include sublingual, injectable, and implantable drug delivery strategies that have the potential to effect rapid and dramatic improvements in schizophrenia outcomes.

Chemosensitization by phenothiazines in human lung cancer cells: impaired resolution of γH2AX and increased oxidative stress elicit apoptosis associated with lysosomal expansion and intense vacuolation

Chemotherapy resistance poses severe limitations on the efficacy of anti-cancer medications. Recently, the notion of using novel combinations of 'old' drugs for new indications has garnered significant interest. The potential of using phenothiazines as chemosensitizers has been suggested earlier but so far our understanding of their molecular targets remains scant. The current study was designed to better define phenothiazine-sensitive cellular processes in relation to chemosensitivity. We found that phenothiazines shared the ability to delay γH2AX resolution in DNA-damaged human lung cancer cells. Accordingly, cells co-treated with chemotherapy and phenothiazines underwent protracted cell-cycle arrest followed by checkpoint escape that led to abnormal mitoses, secondary arrest and/or a form of apoptosis associated with increased endogenous oxidative stress and intense vacuolation. We provide evidence implicating lysosomal dysfunction as a key component of cell death in phenothiazine co-treated cells, which also exhibited more typical hallmarks of apoptosis including the activation of both caspase-dependent and -independent pathways. Finally, we demonstrated that vacuolation in phenothiazine co-treated cells could be reduced by ROS scavengers or the vacuolar ATPase inhibitor bafilomycin, leading to increased cell viability. Our data highlight the potential benefit of using phenothiazines as chemosensitizers in tumors that acquire molecular alterations rendering them insensitive to caspase-mediated apoptosis.

Cellular and molecular actions of Methylene Blue in the nervous system

Methylene Blue (MB), following its introduction to biology in the 19th century by Ehrlich, has found uses in various areas of medicine and biology. At present, MB is the first line of treatment in methemoglobinemias, is used frequently in the treatment of ifosfamide-induced encephalopathy, and is routinely employed as a diagnostic tool in surgical procedures. Furthermore, recent studies suggest that MB has beneficial effects in Alzheimer's disease and memory improvement. Although the modulation of the cGMP pathway is considered the most significant effect of MB, mediating its pharmacological actions, recent studies indicate that it has multiple cellular and molecular targets. In the majority of cases, biological effects and clinical applications of MB are dictated by its unique physicochemical properties including its planar structure, redox chemistry, ionic charges, and light spectrum characteristics. In this review article, these physicochemical features and the actions of MB on multiple cellular and molecular targets are discussed with regard to their relevance to the nervous system.

Discovery of very late antigen-4 (VLA-4, alpha4beta1 integrin) allosteric antagonists

Integrins are cell adhesion receptors that mediate cell-to-cell, or cell-to-extracellular matrix adhesion. They represent an attractive target for treatment of multiple diseases. Two classes of small molecule integrin inhibitors have been developed. Competitive antagonists bind directly to the integrin ligand binding pocket and thus disrupt the ligand-receptor interaction. Allosteric antagonists have been developed primarily for α(L)β(2)- integrin (LFA-1, lymphocyte function-associated antigen-1). Here we present the results of screening the Prestwick Chemical Library using a recently developed assay for the detection of α(4)β(1)-integrin allosteric antagonists. Secondary assays confirmed that the compounds identified: 1) do not behave like competitive (direct) antagonists; 2) decrease ligand binding affinity for VLA-4 ∼2 orders of magnitude; 3) exhibit antagonistic properties at low temperature. In a cell based adhesion assay in vitro, the compounds rapidly disrupted cellular aggregates. In accord with reports that VLA-4 antagonists in vivo induce mobilization of hematopoietic progenitors into the peripheral blood, we found that administration of one of the compounds significantly increased the number of colony-forming units in mice. This effect was comparable to AMD3100, a well known progenitor mobilizing agent. Because all the identified compounds are structurally related, previously used, or currently marketed drugs, this result opens a range of therapeutic possibilities for VLA-4-related pathologies.

The promise and reality of pharmacogenetics in psychiatry

Existing psychotropic medications for the treatment of mental illnesses, including antidepressants, mood stabilizers, and antipsychotics, are clinically suboptimal. They are effective in only a subset of patients or produce partial responses, and they are often associated with debilitating side effects that discourage adherence. There is growing enthusiasm in the promise of pharmacogenetics to personalize the use of these treatments to maximize their efficacy and tolerability; however, there is still a long way to go before this promise becomes a reality. This article reviews the progress that has been made in research toward understanding how genetic factors influence psychotropic drug responses and the challenges that lie ahead in translating the research findings into clinical practices that yield tangible benefits for patients with mental illnesses.

Patterns of spontaneous magnetoencephalographic activity in patients with schizophrenia

Magnetoencephalography noninvasively measures the magnetic fields produced by the brain. Pertinent research articles from 1993 to 2009 that measured spontaneous, whole-head magnetoencephalography activity in patients with schizophrenia were reviewed. Data on localization of oscillatory activity and correlation of these findings with psychotic symptoms are summarized. Although the variety of measures used by different research groups makes a quantitative meta-analysis difficult, it appears that magnetoencephalography activity in patients may exhibit identifiable patterns, defined by topographic organization and frequency band. Specifically, 11 of the 12 studies showed increased theta (4-8 Hz) and delta (1-4 Hz) band oscillations in the temporal lobes of patients; of the 10 studies that examined the relationship between oscillatory activity and symptomatology, 8 found a positive correlation between temporal lobe theta activity and positive schizophrenic symptoms. Abnormally high frontal delta activity was not seen. These findings are analyzed in comparison with the electroencephalogram literature on schizophrenics, and possible confounds (e.g., medication effects) are discussed. In the future, magnetoencephalography might be used to assist in diagnosis or might be fruitfully used in conjunction with new neuroscience research approaches such as computational modeling, which may be able to link oscillatory activity and cellular-level pathology.

The elderly safety imperative and antipsychotic usage

Behavioral and psychotic symptoms are common problems in older adults, and as the population ages, understanding the benefits and risks of antipsychotic usage is increasingly important. In this age group, psychotic symptoms may occur in patients with dementia or as part of schizophrenia, mood disorders, delirium, or delusional disorder. Various antipsychotics have been studied in older adults with psychotic symptoms, demonstrating mixed, but real, benefit, especially in relation to carefully selected patients. Caution is required because of the potential side effects and risks, which include increased mortality and cardiovascular and cerebrovascular events. This article reviews the use of antipsychotics in older adults, with emphasis on the risks and side effects, particularly in dementia patients with behavioral and psychotic symptoms.

The promise and reality of pharmacogenetics in psychiatry

Existing psychotropic medications for the treatment of mental illnesses, including antidepressants, mood stabilizers, and antipsychotics, are clinically suboptimal. They are effective in only a subset of patients or produce partial responses, and they are often associated with debilitating side effects that discourage adherence. There is growing enthusiasm in the promise of pharmacogenetics to personalize the use of these treatments to maximize their efficacy and tolerability; however, there is still a long way to go before this promise becomes a reality. This article reviews the progress that has been made in research toward understanding how genetic factors influence psychotropic drug responses and the challenges that lie ahead in translating the research findings into clinical practices that yield tangible benefits for patients with mental illnesses.

Rapid antipsychotic response with ziprasidone predicts subsequent acute manic/mixed episode remission

OBJECTIVE

To assess rapid antipsychotic efficacy with oral ziprasidone monotherapy in bipolar acute manic/mixed episodes with psychotic features, and predictive value of rapid antipsychotic response for subsequent acute manic/mixed episode remission.

METHODS

Pooled analysis of two 3-week, randomized, double-blind, placebo-controlled trials of ziprasidone (40-160mg/d) in inpatients with bipolar I disorder, and a current manic or mixed episode, with (n=152) or without (n=246) psychotic features. Psychosis improvement was evaluated by change in SADS-C psychosis score (sum of delusions, hallucinations, and suspiciousness items). Rapid antipsychotic response (>or=50% decrease in SADS-C psychosis score by Day 4) and acute manic episode response and remission (endpoint >or=50% MRS decrease, and a MRS score <or=12, respectively) were analyzed.

RESULTS

Significantly greater antipsychotic effects were observed by Day 4 with ziprasidone treatment (vs. placebo) and the magnitude of improvement increased significantly with time, in all subjects, in the subgroup of all psychotic subjects, and psychotic subjects with low baseline agitation (p<0.05). Rapid antipsychotic response predicted subsequent acute manic episode remission independent of ziprasidone or placebo treatment received (p<0.001, ROC AUC=0.71) with significant improvement in accuracy of MRS remission prediction when compared to models using early changes in MRS score alone (p=0.01).

LIMITATIONS

Post hoc analysis, use of 3 SADS-C psychosis items to assess psychosis.

CONCLUSIONS

The predictive value of rapid (Day 4) improvement in psychotic symptoms for subsequent (Day 21) remission of acute manic/mixed symptoms may facilitate enhanced therapeutics, in view of the current practice of brief hospitalization for patients with acute manic/mixed episodes with psychotic features.

Antipsychotic dosing and drug delivery

This chapter addresses the current state of affairs regarding proposed mechanism of action for antipsychotic medications and how this mechanism relates to dosing and delivery strategies. The initial portion describes the history of antipsychotic medication, including key discoveries that contribute to the dopamine hypothesis of schizophrenia and provide evidence that dopamine D2 receptor antagonism remains the most copasetic explanation for both determination of dose and degree of efficacy for current antipsychotic medications. Early observations regarding the unique properties of clozapine and how those observations led to the misconception and misnomer of atypicality are also discussed. Subsequent sections relate the dosing of available medications using chlorpromazine equivalents, with a discussion of non-D2-related mechanisms to antipsychotic effects. The balance of the chapter explores the temporal pattern of receptor occupancy as a key determinant of antipsychotic effectiveness, noting that continuous infusion would present the optimal method of treatment. In addition to the pharmacodynamic benefits of continuous long-term delivery systems, the incidence, causes, and clinical consequences of poor adherence are addressed. These observations are then discussed in the context of clinical studies and meta-analyses, demonstrating superiority of long-term depot preparations over oral administration. However, despite overwhelming evidence in favor of long-term delivery systems, few options are available to provide such ideal medication delivery profiles. Barriers to creating traditional depot preparations for a large number of antipsychotic agents, as well as efforts to address these limitations with polymer-based microspheres are described. The potential extension of current formulations to very long-term delivery implants using biodegradable and nonbiodegradable platforms is then described. Benefits as well as limitations of such systems are discussed with respect to clinical and ethical issues as well as a brief description of potential regulatory and logistic barriers to developing better delivery options. In summary, this chapter describes the basis for relating the dose of all existing antipsychotic medications to dopamine D2 receptor affinity and the potential contribution of continuous occupancy to enhanced efficacy through superior biological effects and improved adherence.

[Serotonin syndrome following methylene blue infusion during parathyroidectomy: a case report and literature review]

PURPOSE

To report a case of autonomic, neurological and neuromuscular instability following methylene blue infusion for parathyroidectomy; to advance the argument for a diagnosis of serotonin syndrome; and to consider this diagnosis in previous, unexplained reports of adverse reactions amongst patients undergoing parathyroidectomy using methylene blue.

CLINICAL FEATURES

Methylene blue was administered to a 58-yr-old woman undergoing a parathyroidectomy under general anesthesia. The patient had a background of obsessive compulsive disorder treated with paroxetine. Postoperatively, she demonstrated symptoms and signs of serotonin syndrome; specifically tachycardia, agitation, dystonia and abnormal eye movements. These clinical findings spontaneously resolved themselves over the subsequent 48 hr.

CONCLUSION

An interaction between methylene blue and serotonergic agents may give rise to the serotonin syndrome. Consideration should be given to avoiding methylene blue in patients taking serotonergic agents. The diagnosis should be considered in patients with autonomic, neuromuscular or neurological changes and should be managed accordingly.

Hybrid approach for the design of highly affine and selective dopamine D3 receptor ligands using privileged scaffolds of biogenic amine GPCR ligands

A series of compounds containing privileged scaffolds of the known histamine H(1) receptor antagonists cetirizine, mianserin, ketotifen, loratadine, and bamipine were synthesized for further optimization as ligands for the related biogenic amine binding dopamine D(3) receptor. A pharmacological screening was carried out at dopamine D(2) and D(3) receptors. In the preliminary testing various ligands have shown moderate to high affinities for dopamine D(3)receptors, for example, N-(4-{4-[benzyl(phenyl)amino]piperidin-1-yl}butylnaphthalen-2-carboxamide (19a) (hD(3)K(i)=0.3 nM; hD(2)K(i)=703 nM), leading to a selectivity ratio of 2343.

The antipsychotic drug trifluoperazine inhibits DNA repair and sensitizes non small cell lung carcinoma cells to DNA double-strand break induced cell death

Trifluoperazine (TFP), a member of the phenothiazine class of antipsychotic drugs, has been shown to augment the cytotoxicity of the DNA-damaging agent bleomycin. In the present study, we investigated the effect of trifluoperazine on (a) survival of bleomycin-treated human non-small cell lung carcinoma U1810 cells, (b) induction and repair of bleomycin-induced DNA strand breaks, and (c) nonhomologous end-joining (NHEJ), the major DNA double-strand break (DSB) repair pathway in mammalian cells. By using a clonogenic survival assay, we show here that concomitant administration of trifluoperazine at a subtoxic concentration enhances the cytotoxicity of bleomycin. Moreover, trifluoperazine also increases the longevity of bleomycin-induced DNA strand breaks in U1810 cells, as shown by both comet assay and fraction of activity released (FAR)-assay. This action seems to be related to suppression of cellular DNA DSB repair activities because NHEJ-mediated rejoining of DSBs occurs with significantly lower efficiency in the presence of trifluoperazine. We propose that TFP might be capable of inhibiting one or more elements of the DNA DSB repair machinery, thereby increasing the cytotoxicity of bleomycin in lung cancer cells.

Novel uses for risperidone: focus on depressive, anxiety and behavioral disorders

Risperidone has been shown to be a safe and effective atypical antipsychotic agent. It was initially approved for the treatment of schizophrenia, and now, in many countries, is used to treat other conditions, including bipolar disorder, dementia and behavior problems in a range of age groups. Yet, frequent off-label use by clinicians to treat other mood and anxiety disorders and behavioral disorders is common and requires an examination of the risks and benefits in such populations. A review of the literature provides varying levels of evidence supporting its use in a range of depressive and anxiety disorders, and in special populations, including children and the elderly. Most reports are based on short-term studies and include its use both as monotherapy and as an augmenting agent to other psychotropics, and in a range of doses. Further randomized controlled trials are needed to confirm the efficacy and tolerability of risperidone, both short- and long-term, in many of these conditions. The published evidence is summarized, with recommendations and suggestions for its use.

Tricyclic antidepressant pharmacology and therapeutic drug interactions updated

New data on the pharmacology of tricyclic antidepressants (TCAs), their affinities for human cloned CNS receptors and their cytochrome P450 enzyme inhibition profiles, allow improved deductions concerning their effects and interactions and indicate which of the TCAs are the most useful. The relative toxicity of TCAs continues to be more precisely defined, as do TCA interactions with selective serotonin reuptake inhibitors (SSRIs). TCA interactions with monoamine oxidase inhibitors (MAOIs) have been, historically, an uncertain and difficult question, but are now well understood, although this is not reflected in the literature. The data indicate that nortriptyline and desipramine have the most pharmacologically desirable characteristics as noradrenaline reuptake inhibitors (NRIs), and as drugs with few interactions that are also safe when coadministered with either MAOIs or SSRIs. Clomipramine is the only available antidepressant drug that has good evidence of clinically relevant serotonin and noradrenaline reuptake inhibition (SNRI). These data assist drug selection for monotherapy and combination therapy and predict reliably how and why pharmacodynamic and pharmacokinetic interactions occur. In comparison, two newer drugs proposed to have SNRI properties, duloxetine and venlafaxine, may have insufficient NRI potency to be effective SNRIs. Combinations such as sertraline and nortriptyline may therefore offer advantages over drugs like venlafaxine that have fixed ratios of SRI/NRI effects that are not ideal. However, no TCA/SSRI combination is sufficiently safe to be universally applicable without expert knowledge. Standard texts (e.g. the British National Formulary) and treatment guidelines would benefit by taking account of these new data and understandings.

Cytokines in schizophrenia and the effects of antipsychotic drugs

Growing evidence suggests that the immune, endocrine, and nervous systems interact with each other through cytokines, hormones, and neurotransmitters. The activation of the cytokine systems may be involved in the neuropathological changes occurring in the central nervous system (CNS) of schizophrenic patients. Numerous studies report that treatment with antipsychotic drugs affects the cytokine network. Hence, it is plausible that the influence of antipsychotics on the cytokine systems may be responsible for their clinical efficacy in schizophrenia. This article reviews current data on the cytokine-modulating potential of antipsychotic drugs. First, basic information on the cytokine networks with special reference to their role in the CNS as well as an up-to-date knowledge of the cytokine alterations in schizophrenia is outlined. Second, the hitherto published studies on the influence of antipsychotics on the cytokine system are reviewed. Third, the possible mechanisms underlying antipsychotics' potential to influence the cytokine networks and the most relevant aspects of this activity are discussed. Finally, limitations of the presented studies and prospects of future research are delineated.

Combination antipsychotic therapy in psychiatric outpatient clinics in Taiwan

OBJECTIVE

The purpose of this study is to survey the use of combination antipsychotic therapy (CAT) in the psychiatric outpatient clinic of a general hospital.

METHODS

Patients who received at least 2 antipsychotics in the psychiatric outpatient clinic of a general hospital in 1 month (August 1-31, 2003) were identified, and their retrospective chart review was performed. Using a questionnaire, we surveyed the clinicians on why 2 antipsychotics were prescribed, why long-term CAT was used, and whether the problems were solved by CAT.

RESULTS

We studied 957 patients diagnosed with schizophrenia and related disorders in 1 month. A total of 119 patients (12%) were prescribed at least 2 antipsychotics. Among these 119 patients, 91 (76%) were prescribed 2 types of first-generation antipsychotics (FGAs), and 15 patients (16%) were prescribed a second-generation antipsychotic medication and a low-dose FGA medication. The clinicians' main reasons for CAT were to treat insomnia (84%) and psychotic symptoms (83%).

CONCLUSIONS

The results of this study revealed that 12% of the patients received CAT in the clinical practice. Most patients were prescribed 2 FGAs. The clinicians' reasons for prescribing CAT in Taiwan were to treat insomnia and psychotic symptoms.

Antipsychotic drug action: targets for drug discovery with neurochemical imaging

Schizophrenia is a serious lifelong mental illness for which current treatments may only be partially effective. All antipsychotic medications available at present are thought to exert their main antipsychotic effect through antagonism of dopamine D2 receptors. Clozapine is the most effective antipsychotic drug currently available, but it can cause serious side effects, including agranulocytosis and diabetes. Pharmacologic factors that distinguish clozapine from other antipsychotic drugs have been studied to try to develop safer drugs with similar efficacy to clozapine. These have met with limited success. Neurochemical imaging techniques, such as positron emission tomography, single photon emission tomography and magnetic resonance spectroscopy, have been used to study antipsychotic drug action in living human subjects. These techniques shed a great deal of light on the mechanisms of antipsychotic action and have revealed a number of novel targets for future drug development in schizophrenia. Next-generation antipsychotic medications will aim to improve on the efficacy and tolerability of currently available medications. The authors believe that they are likely to achieve this through drug action at non-D2 sites. Future research and drug development, including the development of medications to prevent progression from the prepsychotic stage to schizophrenia, will rely heavily on neurochemical imaging methods at all stages in the drug-discovery pipeline.

Does clozapine work by blocking spikes and sparing bursts?

Clozapine works better and produces fewer side effects than other antipsychotics. Existing hypotheses fail to explain why. A new hypothesis, single spike suppression, supposes that psychotic symptoms are mediated by the single spikes of neurons at the D2 receptor. All antipsychotics block these spikes. Clozapine, according to the hypothesis, blocks these spikes but, unlike other antipsychotics, spares the spike bursts that mediate movement, cognition and affect. This study explores the mathematical feasibility of single spike suppression. Could an antipsychotic with the right receptor kinetics selectively block single spikes? Could this selectivity have clinical consequences? To develop the hypothesis, the author made a mathematical model of the receptor occupancy of a synapse, and performed five simulations, varying input data within the range established by research. The effects of hypothetical antipsychotics on single spikes and bursts were compared. The author confirmed that a drug with the right dissociation rate constant (k off) would dissociate slowly enough to block single spikes, but rapidly enough to spare longer bursts. If the hypothesis is correct, this spike-selective, burst-sparing drug would work at relatively low D2 occupancies, and cause minimal D2-related side effects. Single spike suppression may explain the superior properties of clozapine better than competing hypotheses. If so, it would provide a better model for a new generation of safe, effective antipsychotics.

History of the discovery and clinical introduction of chlorpromazine

BACKGROUND

The historical process of discovery and clinical introduction of chlorpromazine, one of the greatest advances of 20th century medicine and history of psychiatry, is analyzed.

METHODS

In this review, we have studied the original works of pioneers in the discovery and clinical use of chlorpromazine, as well as the contributions of prestigious researchers (historians, pharmacologists, psychiatrists, etc.) about this topic.

RESULTS

The discovery of phenothiazines, the first family of antipsychotic agents has its origin in the development of German dye industry, at the end of the 19th century (Graebe, Liebermann, Bernthsen). Up to 1940 they were employed as antiseptics, antihelminthics and antimalarials (Ehrlich, Schulemann, Gilman). Finally, in the context of research on antihistaminic substances in France after World War II (Bovet, Halpern, Ducrot) the chlorpromazine was synthesized at Rhône-Poulenc Laboratories (Charpentier, Courvoisier, Koetschet) in December 1950. Its introduction in anaesthesiology, in the antishock area (lytic cocktails) and "artificial hibernation" techniques, is reviewed (Laborit), and its further psychiatric clinical introduction in 1952, with initial discrepancies between the Parisian Val-de-Grâce (Laborit, Hamon, Paraire) and Sainte-Anne (Delay, Deniker) hospital groups. The first North-American publications on chlorpromazine took place in 1954 (Lehmann, Winkelman, Bower). The introduction of chlorpromazine in the USA (SKF) was more difficult due to their strong psychoanalytic tradition. The consolidation of the neuroleptic therapy took place in 1955, thanks to a series of scientific events, which confirmed the antipsychotic efficacy of the chlorpromazine.

CONCLUSIONS

The discovery of the antipsychotic properties of chlorpromazine in the 1950s was a fundamental event for the practice of psychiatry and for the genesis of the so-called "psychopharmacological revolution."

Neuroleptics in Headache

OBJECTIVES

To review the mechanism of action of neuroleptics, the evidence for their efficacy, and their clinical use in headache treatment.

BACKGROUND

Neuroleptics and antiemetics have long been used for headache treatment; however, they have not been widely utilized because of general unfamiliarity with them and concerns about their adverse events. With the recent advent of the atypical neuroleptics and their improved adverse event profile, our armamentarium for headache treatment has expanded. In this review, we explore the mechanism of action of these classes of drugs, their adverse events, and the evidence for their efficacy. We also detail our experience with the different drugs and how we use them as both acute and preventive headache therapy.

DESIGN

A review of published literature was obtained through a MEDLINE search on the use of neuroleptics in headache therapy.

CONCLUSION

Neuroleptics have widespread evidence supporting their use in headache treatment and present an important part of the armaterium against headache.

Prolonged postoperative disorientation after methylene blue infusion during parathyroidectomy

Methylene blue 7.5 mg/kg is frequently given at our institution during parathyroidectomy. The dye preferentially stains the parathyroids so as to provide better surgical visualization. Other than causing a pseudocyanosis, the technique is generally considered to be rather innocuous. We report a case of a patient who, after this procedure, had a postoperative course that was unusual because of slowly resolving altered mental status.

Toxicity and carcinogenicity studies of chlorpromazine hydrochloride and p-cresidine in the p53 heterozygous mouse model

The carcinogenic potential of chlorpromazine hydrochloride, a psychotropic agent, was assessed in the p53 heterozygous mouse assay. In a 4-week dose range finding study in p53 wild-type mice, doses of 20,40, 60, and 80 mg/kg were poorly tolerated because of mortality secondary to the severe sedative and hypotensive effects of chlorpromazine. Based on 40% mortality at a dose of 20 mg/kg in the dose-range finding study, a high dose of 10 mg/kg was chosen for the 26-week carcinogenicity study in p53 heterozygous mice. Doses of 2.5, 5, and 10 mg/kg chlorpromazine hydrochloride were well tolerated in the 26-week study. The administration of chlorpromazine hydrochloride at dose levels up to and including 10 mg/kg to p53 heterozygous and wild-type mice did not result in a dose-related increase in tumor incidence or in the type of tumors seen in comparison to controls. Findings related to the administration of chlorpromazine in the 26-week study were limited to minimal uterine and ovarian atrophy in p53 wild-type mice dosed with 10 mg/kg chlorpromazine hydrochloride. However, p53 heterozygous mice administered 400 mg/kg p-cresidine, a genotoxic carcinogen commonly used as a positive control for this model, developed urinary bladder tumors. Administration of p-cresidine also resulted in a regenerative anemia, splenic and hepatic hemosiderosis, renal findings, and ovarian and uterine atrophy. This study demonstrated that chlorpromazine hydrochloride, at the doses tolerated, was not carcinogenic in the p53 heterozygous mouse assay.

The substituted benzamides and their clinical potential on dysthymia and on the negative symptoms of schizophrenia

In this paper the historical and scientific background that led to the use of substituted benzamides in two apparently unrelated clinical conditions namely dysthymic disorder and schizophrenia will be reviewed, in order to understand if a common mechanism of action may support this dual therapeutic indication. The dopaminergic antidepressant action of substituted benzamides such as sulpiride, has been proposed, since the late 1970s, by several authors and extensively explored in preclinical experiments by our group. In Italy the first marketing authorization obtained for the new substituted benzamide amisulpride, was with the sole indication of dysthymia and therefore a solid clinical experience exists in the use of substituted benzamides in mild forms of depression, with more than 1 000 000 patients being treated in the last 7 years. The proposed mechanism of action of substituted benzamides implies a selective modulation of the dopaminergic system in the mesocorticolimbic area, important for cognitive processing of internal and external cues, related to survival. The selective antagonism of dopamine D2-D3 receptors has been evoked to explain, in small to moderate doses (ie 50-100 mg day(-1)), the antidepressant effect and, in moderate to medium doses (100-400 mg day(-1)), the reported efficacy on negative symptoms of schizophrenia. Thus, substituted benzamides could represent the first class of atypical antipsychotics successfully employed for both depressive states and schizophrenia. Interestingly, recent evidence in the literature suggests that depressive episodes belonging to the bipolar spectrum are among "alternative indications" of other atypical antipsychotics such as olanzapine and risperidone.

Inhibition of skeletal muscle nicotinic receptors by the atypical antipsychotic clozapine

We have previously observed that certain atypical antipsychotic drugs reduce the amplitude and duration of miniature end-plate currents (EPCs) at the frog neuromuscular junction (Effects of atypical antipsychotics on vertebrate neuromuscular transmission, Nguyen, Q.-T., Yang, J., Miledi, R. Neuropharmacology 42, 2002, 670-676), therefore suggesting that these drugs act on nicotinic acetylcholine receptors. In this study we examined the effects of the atypical antipsychotic clozapine on nicotinic receptors of frog neuromuscular end-plates or in Xenopus oocytes expressing the alpha(1)beta(1)gamma delta mouse skeletal muscle nicotinic receptor. At neuromuscular junctions, postsynaptic currents were reduced by micromolar concentrations of clozapine. This compound also acted presynaptically by increasing the quantal content of EPCs of muscles without noticeably affecting paired-pulse facilitation. In oocytes, clozapine inhibited alpha(1)beta(1)gamma delta receptors with an IC(50) of 10 microM and a Hill coefficient of 1. Blockage of alpha(1)beta(1)gamma delta receptors by clozapine bears several hallmarks of open-channel blockers, including faster response decays, strong voltage dependence of the block, large rebound currents upon wash, and reduction of peak responses even at saturating concentrations of acetylcholine. However, clozapine increased the EC(50) for acetylcholine and its blocking effect was enhanced by preincubation. These results suggest that clozapine antagonizes muscle nicotinic receptors by blocking open channels, and possibly also by another mechanism which still remains to be investigated.

Inhibition of human alpha1E subunit-mediated ca2+ channels by the antipsychotic agent chlorpromazine

Chlorpromazine is a neuroleptic antipsychotic agent with a long history of clinical use. Its primary mode of action is thought to be through modulation of monoaminergic inter-neuronal communication; however, its side-effect profile indicates substantial activities in other systems. Recent work has begun to uncover actions of this compound on ion channels. In this light we have investigated the actions of chlorpromazine on the recombinant alpha1E subunit-encoded voltage-sensitive Ca2+ channel (VSCC) that is believed to encode drug-resistant R-type currents found in neurones and other cells. Chlorpromazine produced a dose-dependent antagonism of these channels that was reversed on drug removal. The mean IC50 was close to 10 microM. At this concentration, the level of antagonism observed was dependent on the membrane potential, with greater inhibition being observed at more negative test potentials. Furthermore, chlorpromazine induced substantial changes in the steady-state inactivation properties of alpha1Ebeta3-mediated currents, although it was not seen to elicit a corresponding change in inactivation kinetics. These results are discussed with regard to the possible clinical mechanisms of chlorpromazine actions.

Inhibition of nicotinic acetylcholine receptors and calcium channels by clozapine in bovine adrenal chromaffin cells

The effects of clozapine on the activities of nicotinic acetylcholine receptors (nAChRs) and voltage-sensitive calcium channels (VSCCs) were investigated and compared with those of chlorpromazine (CPZ) in bovine adrenal chromaffin cells. [(3)H]Norepinephrine ([(3)H]NE) secretion induced by activation of nAChRs was inhibited by clozapine and CPZ with half-maximal inhibitory concentrations (IC(50)) of 10.4 +/- 1.1 and 3.9 +/- 0.2 microM, respectively. Both cytosolic calcium increase and inward current in the absence of extracellular calcium induced by nicotinic stimulation were also inhibited by clozapine and CPZ, but the greater inhibition was achieved by CPZ. In addition, [(3)H]nicotine binding to chromaffin cells was inhibited by clozapine and CPZ with IC(50) values of approximately 19 and 2 microM, respectively. On the other hand, [(3)H]NE secretion induced by high K(+) was inhibited by clozapine and CPZ with similar IC(50) values of 15.5 +/- 3.8 and 17.1 +/- 3.9 microM, respectively. Our results suggest that clozapine, as well as CPZ, inhibits nAChRs and VSCCs, thereby causing inhibition of catecholamine secretion, and that clozapine is much less potent than CPZ in inhibiting nAChRs.