Switching antipsychotics. Antipsychotic tolerance, withdrawal and relapse: unresolved issues and research implications

Clozapine-induced gastroesophageal rumination in 22q11.2 Deletion Syndrome. A case report on gastroesophageal side effects management without renouncing clozapine's effectiveness

Despite entailing more severe and uncommon side effects in 22q11.2DS compared to idiopathic schizophrenia, we strongly believe that clozapine should continue to be considered the gold standard for all treatment-resistant schizophrenia, even in 22qDS.

Antipsychotic Induced Dopamine Supersensitivity Psychosis: A Comprehensive Review

Chronic prescription of antipsychotics seems to lose its therapeutic benefits in the prevention of recurring psychotic symptoms. In many instances, the occurrence of relapse from initial remission is followed by an increase in dose of the prescribed antipsychotic. The current understanding of why this occurs is still in its infancy, but a controversial idea that has regained attention recently is the notion of iatrogenic dopamine supersensitivity. Studies on cell cultures and animal models have shown that long-term antipsychotic use is linked to both an upregulation of dopamine D₂-receptors in the striatum and the emergence of enhanced receptor affinity to endogenous dopamine. These findings have been hypothesized to contribute to the phenomenon known as dopamine supersensitivity psychosis (DSP), which has been clinically typified as the foundation of rebound psychosis, drug tolerance, and tardive dyskinesia. The focus of this review is the update of evidence behind the classification of antipsychotic induced DSP and an investigation of its relationship to treatment resistance. Since antipsychotics are the foundation of illness management, a greater understanding of DSP and its prevention may greatly affect patient outcomes.

Antipsychotic-induced sensitization and tolerance: Behavioral characteristics, developmental impacts, and neurobiological mechanisms

Antipsychotic sensitization and tolerance refer to the increased and decreased drug effects due to past drug use, respectively. Both effects reflect the long-term impacts of antipsychotic treatment on the brain and result from the brain's adaptive response to the foreign property of the drug. In this review, clinical evidence of the behavioral aspect of antipsychotic sensitization and tolerance is selectively reviewed, followed by an overview of preclinical literature that examines these behavioral characteristics and the related pharmacological and nonpharmacological factors. Next, recent work on the developmental impacts of adolescent antipsychotic sensitization and tolerance is presented and recent research that delineates the neurobiological mechanisms of antipsychotic sensitization and tolerance is summarized. A theoretical framework based on "drug learning and memory" principles is proposed to account for the phenomena of antipsychotic sensitization and tolerance. It is maintained that antipsychotic sensitization and tolerance follow basic principles of learning or acquisition ("induction") and memory ("expression"). The induction and expression of both effects reflect the consequences of associative and nonassociative processing and are strongly influenced by various pharmacological, environmental, and behavioral factors. Drug-induced neuroplasticity, such as functional changes of striatal dopamine D2 and prefrontal serotonin (5-HT)2A receptors and their mediated signaling pathways, in principle, is responsible for antipsychotic sensitization and tolerance. Understanding the behavioral characteristics and neurobiological underpinnings of antipsychotic sensitization and tolerance has greatly enhanced our understanding of mechanisms of antipsychotic action, and may have important implications for future drug discovery and clinical practice.

Association Between Antipsychotic Use and Risk of Acute Myocardial Infarction

Background—

Antipsychotic medications have been increasingly and more widely prescribed despite continued uncertainty about their association with the incidence of acute myocardial infarction (AMI).

Methods and Results—

We investigated the risk of AMI associated with antipsychotic treatment in 56 910 patients with schizophrenia, mood disorders, or dementia first hospitalized or visiting an emergency room for AMI in 1999 to 2009. A case-crossover design was used to compare the distributions of antipsychotic exposure for the same patient across 1 to 30 and 91 to 120 days just before the AMI event. Adjustments were made for comedications and outpatient visits. The adjusted odds ratio of AMI risk was 2.52 (95% confidence interval, 2.37–2.68) for any antipsychotics, 2.32 (95% confidence interval, 2.17–2.47) for first-generation antipsychotics, and 2.74 (95% confidence interval, 2.49–3.02) for second-generation antipsychotics. The risk significantly increased ( P <0.001) with elevations in dosage and in short-term use (≤30 days). Male patients, elderly patients, and patients with dementia were at significantly increased risk (all P <0.001). Physically healthier patients with no preexisting diabetes mellitus, hypertension, or dyslipidemia were at significantly greater risk ( P <0.001), largely because they had been exposed to higher doses of antipsychotics ( P <0.001). A study of the selected binding of antipsychotics to 14 neurotransmitter receptors revealed only dopamine type 3 receptor antagonism to be significantly associated with AMI risk (adjusted odds ratio, 2.59; 95% confidence interval, 2.43–2.75; P <0.0001).

Conclusions—

Antipsychotic use may be associated with a transient increase in risk for AMI, possibly mediated by dopamine type 3 receptor blockades. Further education on drug safety and research into the underlying biological mechanisms are needed.

Antipsychotic dosing: found in translation

In the field of schizophrenia research, as in other areas of psychiatry, there is a sense of frustration that greater advances have not been made over the years, calling into question existing research strategies. Arguably, many purported gains claimed by research have been "lost in translation," resulting in limited impact on diagnosis and treatment in the clinical setting. There are exceptions; for example, we would argue that different lines of preclinical and clinical research have substantially altered how we look at antipsychotic dosing. While this story remains a work in progress, advances "found in translation" have played an important role. Detailing these changes, the present paper speaks to a body of evidence that has already shifted clinical practice and raises questions that may further alter the manner in which antipsychotics have been administered over the last 6 decades.

Hospitalisation Utilisation and Costs in Schizophrenia Patients in Finland before and after Initiation of Risperidone Long-Acting Injection

Objectives. Quantify changes in hospital resource use in Finland following initiation of risperidone long-acting injection (RLAI). Materials and Methods. A retrospective multi-center chart review (naturalistic setting) was used to compare annual hospital bed-days and hospital episodes for 177 schizophrenia patients (mean age 47.1 years, 52% female, 72% hospitalized) before and after initiation of RLAI (between January 2004 and June 2005) using the within-patient "mirror-image" study design. The base case analytical approach allocated hospital episodes overlapping the start date entirely to the preinitiation period. In order to investigate the impact of inpatient care ongoing at baseline, the change in bed-days was also estimated using an alternative analytical approached related to economic modelling. Results. In the conventional analysis, the mean annual hospitalisation costs declined by €11,900 and the number of bed-days was reduced by 40%, corresponding to 0.19 fewer hospital episodes per year. The reductions in bed-days per patient-year were similar for patients switched to RLAI as inpatients and as outpatients. In the modelling-based analysis, an 8% reduction in bed-days per year was observed. Conclusion. Despite uncertainty in the choice of analytic approach for allocating inpatient episodes that overlapping this initiation, consistent reductions in resource use are associated with the initiation of RLAI in Finland.

Switching from conventional antipsychotics to ziprasidone: a randomized, open-label comparison of regimen strategies

In clinical psychopharmacology, the optimal method of switching from treatment A to treatment B with regard to efficacy and tolerability is an important area of study. We investigated the effects on efficacy and tolerability of switching patients from conventional antipsychotics to ziprasidone. This was a 6-week open-label, randomized study of 54 patients with persistent schizophrenia or schizoaffective disorder. Patients received ziprasidone 40 mg BID for 2 days, with titration up to 80 mg BID thereafter. The switch from conventional antipsychotics to ziprasidone was achieved using one of three discrete schedules: (1) abrupt discontinuation of conventional antipsychotics on day 1; (2) fast taper-50% of conventional antipsychotic dosage on days 1 through 7, followed by discontinuation and (3) slow taper-100% of conventional antipsychotic dosage on days 1 and 2, followed by 50% on days 3 through 7, then discontinuation. We found some evidence that the slow-taper strategy was associated with greater reductions in BPRS total scores early in the study compared to the other two strategies. However, these differences did not remain significant at endpoint, suggesting that there was no overall difference between the strategies.

Immediate versus gradual suspension of previous treatments during switch to aripiprazole: results of a randomized, open label study

The aim of the present work was to investigate possible differences in terms of efficacy and tolerability between different switching options to aripiprazole. 77 subjects were randomly assigned to (1) administration of aripiprazole (10 mg) with simultaneous discontinuation of current antipsychotic; (2) administration of aripiprazole (10 mg) and tapering off current antipsychotic over 4 weeks with half dose after the first 2 weeks; (3) administration of aripiprazole (10 mg) and tapering off current antipsychotic over 6 weeks with half dose after the first 2 weeks. Efficacy assessments included CGI-S, CGI-I, BPRS and SANS. Safety assessments included SAS, BAS and AIMS. Severity of symptoms significantly decreased from baseline over the 12 weeks of treatment. Patients switched to aripiprazole with immediate discontinuation of the previous antipsychotic showed an increase of symptoms' severity at week 1. However, severity of side effects did not overall change significantly during the 12-weeks follow-up. Previous treatment's tapering off strategy for switching patients to aripiprazole could be preferable as compared to abrupt discontinuation, in order to prevent early worsening of symptoms and premature discontinuation of treatment, though this results has to be considered with caution given the limitations of the study.