Epidemiology of tardive dyskinesia: Is risk declining with modern antipsychotics?

Genetic underpinnings of tardive dyskinesia: passing the baton to pharmacogenetics

Manifestation of tardive dyskinesia (TD) among schizophrenia subjects on long-term antipsychotic treatment with typical drugs has been a clinical concern. Despite its association with extrapyramidal symptoms, typical drugs are still routinely prescribed globally though marginally superior atypical drugs have long been available. The genetic component in the etiology of TD is well documented. Search for these determinants has led to a few consensus associations of CYP2D6 *10, CYP1A2*1F, DRD2 Taq1A (rs1800497), DRD3 Ser9Gly (rs6280) and MnSOD Ala9Val (rs4880) variants with TD. However, translation of these observations into the clinic has not been achieved so far. This review discusses the salient features of TD etiopathology, current status of TD genetics, interactions between genetic and nongenetic factors, some major drawbacks, challenges and expected focus in TD research over the next decade, with emphasis on pharmacogenetics.

Manganese superoxide dismutase gene Ala-9Val polymorphism might be related to the severity of abnormal involuntary movements in Korean schizophrenic patients

OBJECTIVE

This study examined whether the manganese superoxide dismutase (MnSOD) gene Ala-9Val single-nucleotide polymorphism (SNP) is associated with neuroleptic-induced tardive dyskinesia (TD) and the severity of the abnormal involuntary movements in Korean schizophrenic patients.

METHOD

We investigated whether the MnSOD gene Ala-9Val SNP is associated with TD in Korean schizophrenic patients with (n=83) and without (n=126) TD who were matched for exposure to antipsychotics and other relevant variables.

RESULTS

Logistic regression analysis revealed that being older (p=0.026) was a risk factor for TD, but that there was no significant association between MnSOD gene and TD. Abnormal involuntary movements were more severe in carriers of the Ala allele than in noncarriers (p=0.044).

CONCLUSION

These findings do not support that the MnSOD gene Ala-9Val SNP is associated with TD in Korean schizophrenic patients. However, this polymorphism might be related to the severity of abnormal involuntary movements in this population.

Extrapyramidal side-effects of antipsychotics in a randomised trial

BACKGROUND

There are claims that second-generation antipsychotics produce fewer extrapyramidal side-effects (EPS) compared with first-generation drugs.

AIMS

To compare the incidence of treatment-emergent EPS between second-generation antipsychotics and perphenazine in people with schizophrenia.

METHOD

Incidence analyses integrated data from standardised rating scales and documented use of concomitant medication or treatment discontinuation for EPS events. Mixed model analyses of change in rating scales from baseline were also conducted.

RESULTS

There were no significant differences in incidence or change in rating scales for parkinsonism, dystonia, akathisia or tardive dyskinesia when comparing second-generation antipsychotics with perphenazine or comparing between second-generation antipsychotics. Secondary analyses revealed greater rates of concomitant antiparkinsonism medication among individuals on risperidone and lower rates among individuals on quetiapine, and lower rates of discontinuation because of parkinsonism among people on quetiapine and ziprasidone. There was a trend for a greater likelihood of concomitant medication for akathisia among individuals on risperidone and perphenazine.

CONCLUSIONS

The incidence of treatment-emergent EPS and change in EPS ratings indicated that there are no significant differences between second-generation antipsychotics and perphenazine or between second-generation antipsychotics in people with schizophrenia.

No association between the brain-derived neurotrophic factor gene Val66Met polymorphism and tardive dyskinesia in schizophrenic patients

OBJECTIVE

This study investigated whether the brain-derived neurotrophic factor (BDNF) gene Val66Met single-nucleotide polymorphism (SNP) is associated with antipsychotic-induced tardive dyskinesia (TD) in schizophrenia.

METHODS

Genotyping was performed for the BDNF gene Val66Met SNP in Korean schizophrenic patients with (n=83) and without TD (n=126) who were matched for antipsychotic drug exposure and other relevant variables.

RESULTS

The frequencies of genotypes (chi2=2.37, p=0.306) and alleles (chi2=0.03, p=0.867) did not differ significantly between these two groups.

CONCLUSION

These findings suggest that the BDNF polymorphism does not play a major role in the susceptibility to TD in schizophrenic patients.

Safety profile of iloperidone: a pooled analysis of 6-week acute-phase pivotal trials

Iloperidone, a mixed D2/5-HT2 antagonist, is currently in clinical development for the treatment of schizophrenia. This article assesses the short-term safety of iloperidone using a pooled analysis of 3 phase 2, short-term acute schizophrenia studies conducted between 1998 and 2002 (N = 1943). Patients exposed to 3 dose ranges of iloperidone, another antipsychotic, or placebo were compared on rates of serious adverse events (SAEs), adverse events (AEs), extrapyramidal symptoms, akathisia, prolactin, weight and metabolic parameters, QTc, and other standard safety parameters. The most common treatment-related AEs observed with iloperidone were dizziness, headache, dry mouth, nausea, and insomnia. Discontinuation due to AEs was 4.8% for iloperidone, 7.6% for haloperidol, 6.2% for risperidone, and 4.8% for placebo. Iloperidone groups showed better overall performance on the Extrapyramidal Symptom Rating Scale and Barnes Akathisia Scale than risperidone or haloperidol groups. Patients taking iloperidone experienced a mild weight increase (range, 1.5-2.1 kg) similar to that of risperidone (1.5 kg), whereas those on haloperidol and placebo showed mean weight loss (-0.1 kg and -0.3 kg, respectively). QTc interval significantly increased across all iloperidone groups (least squares mean change from baseline to end point, 2.9-9.1 msec) and for haloperidol (5.0 msec). No significant QTc changes occurred in the risperidone or placebo groups. Iloperidone was associated with no change from baseline in total cholesterol, mild elevation in serum glucose, and slight decrease in triglycerides. Prolactin levels decreased with iloperidone and increased significantly with risperidone and haloperidol. These short-term trials suggest that iloperidone has a reassuring safety profile in many of the areas that are of potential concern, including relatively low dropout rates because of AEs, low extrapyramidal symptoms, akathisia, and prolactin elevation, and a modest short-term effect on weight gain.

World Psychiatric Association Pharmacopsychiatry Section statement on comparative effectiveness of antipsychotics in the treatment of schizophrenia

Data from two major government-funded studies of comparative antipsychotic effectiveness in schizophrenia contradict the widely prevalent belief that the newer second-generation medications are vastly superior to the older first-generation drugs. This has caused uncertainty among patients, clinicians and policy-makers about the relative utility of first- and second- generation antipsychotic agents in its treatment. To reduce confusion and provide a contextual understanding of the new data, the World Psychiatry Association Section on Pharmacopsychiatry comprehensively reviewed the literature on the comparative effectiveness of different antipsychotic treatments for schizophrenia and developed this update. Utilizing data from the approximately 1,600 randomized controlled trials of antipsychotic treatment in schizophrenia, we applied the two indirect and one direct method to comparing the effectiveness of 62 currently-available antipsychotic agents. The subclasses of 51 first-generation and 11 second-generation antipsychotics were both found to be very heterogeneous, with substantial differences in side-effect profiles among members. Second-generation antipsychotic agents were found to be inconsistently more effective than first-generation agents in alleviating negative, cognitive, and depressive symptoms and had a lower liability to cause tardive dyskinesia; these modest benefits were principally driven by the ability of second-generation antipsychotics to provide equivalent improvement in positive symptoms along with a lower risk of causing extrapyramidal side-effects. Clozapine was found to be more efficacious than other agents in treatment-refractory schizophrenia. There were no consistent differences in efficacy among other second-generation antipsychotic agents; if such differences exist, they are likely small in magnitude. Dosing was found to be a key variable in optimizing effectiveness of both first- and second- generation antipsychotic agents. There was enormous individual variability in antipsychotic response and vulnerability to various adverse effects. In contrast to their relatively similar efficacy in treating positive symptoms, there were substantial differences among both first- and second- generation antipsychotic agents with regard to their propensity to cause extrapyramidal, metabolic and other adverse effects; second-generation agents have a lower liability to cause acute extrapyramidal symptoms and tardive dyskinesia along with a tendency to cause greater metabolic side-effects than first-generation agents. Based on these data about the comparative effectiveness of different antipsychotic treatment options, we summarize elements of current best antipsychotic practice for the treatment of schizophrenia and discuss the role of government and the pharmaceutical industry in obtaining and disseminating information which can facilitate best practice.

Efficacy and tolerability of second-generation antipsychotics in children and adolescents with schizophrenia

Early-onset schizophrenia-spectrum (EOSS) disorders (onset of psychotic symptoms before 18 years of age) represent a severe variant associated with significant chronic functional impairment and poor response to antipsychotic treatment. All drugs with proven antipsychotic effects block dopamine D(2) receptors to some degree. The ongoing development of the dopamine and other neurotransmitter receptor systems during childhood and adolescence may affect clinical response and susceptibility to side effects in youth. A literature search was conducted of clinical trials of antipsychotics in children and adolescents with EOSS disorders between 1980 and 2007 from the Medline database, reference lists, and conference proceedings. Trials were limited to double-blind studies of duration of 4 or more weeks that included 15 or more patients. Ten clinical trials were identified. Antipsychotic medications were consistently found to reduce the severity of psychotic symptoms in children and adolescents when compared with placebo. The superiority of clozapine has been now demonstrated relative to haloperidol, standard-dose olanzapine, and "high-dose" olanzapine for EOSS disorders. However, limited comparative data are available regarding whether there are differences among the remaining second-generation antipsychotics (SGAs) in clinical effectiveness. The available data from short-term studies suggest that youth might be more sensitive than adults to developing antipsychotic-related adverse side effects (eg, extrapyramidal side effects, sedation, prolactin elevation, weight gain). In addition, preliminary data suggest that SGA use can lead to the development of diabetes in some youth, a disease which itself carries with it significant morbidity and mortality. Such a substantial risk points to the urgent need to develop therapeutic strategies to prevent and/or mitigate weight gain and diabetes early in the course of treatment in this population.

The evaluation and management of patients with first-episode schizophrenia: a selective, clinical review of diagnosis, treatment, and prognosis

Patients who present with a first episode of psychosis pose many challenges to psychiatry. While some morbidity from schizophrenia is probably not modifiable once acute psychosis has occurred, the best management of this stage of illness nevertheless holds the promise of improving long-term outcomes. We review the clinical literature on first-episode psychosis to derive clinical guidance with regard to timely diagnosis and optimal pharmacological and nonpharmacological treatment. We describe the illness course and the prognosis for this acute phase of illness and the immediate, postpsychotic period.

Understanding and treating "first-episode" schizophrenia

"First-episode schizophrenia" is a clinical and research term that often is used to emphasize the special issues that arise when working with this patient population. The notion that schizophrenia has an inexorable downhill course or is a deteriorating illness is being challenged by more sophisticated understanding of what happens before the initial episode and new understanding of the interactions between biologic vulnerabilities and specific environmental risk during adolescence and early adulthood, such as marijuana use. While the incidence rate of "first-episode" will make this a relatively small percentage of a usual clinical caseload, it is a critically important time for the future course of the illness. The hope is that proper management during this critical period will favorably influence the long-term trajectory of outcome for this individual patient. A growing body of evidence suggests that certain approaches and interventions are more helpful than others, such as understanding of the overwhelming nature of the experience to patients and families, aiming to achieve a full and broad pharmacologic response to initial antipsychotic therapy, while also being on the lookout for vulnerability and extreme sensitivity to side effects, and to anticipate a high likelihood of premature medication discontinuation. Clinicians and treatment services should try to identify "first-episode" patients in time to be able to anticipate and address these issues.

Evaluating the cost-effectiveness of reduced tardive dyskinesia with second-generation antipsychotics

BACKGROUND

Second-generation antipsychotics may have few advantages over older, cheaper drugs, except for possibly reduced risk of tardive dyskinesia.

AIMS

To evaluate the cost-effectiveness of second-generation antipsychotics with regard to reducing tardive dyskinesia.

METHOD

Literature was reviewed on risk of tardive dyskinesia with second-generation antipsychotics; on severity, duration and impairment of tardive dyskinesia; and on the relationship of this disorder to quality of life and quality-adjusted life-years (QALYs). Diverse cost and benefit assumptions and of 1-year and 5-year planning horizons were examined in a deterministic sensitivity analysis.

RESULTS

Estimating 0.143 QALYs lost per case of severe tardive dyskinesia, 1-year cost-effectiveness cumulative estimates ranged from pounds 74,000 (dollars 149,000) to pounds 342,000 (dollars 683,000) per QALY, all above the conventional policy threshold of pounds 25,000 (dollars 50,000).

CONCLUSIONS

Reduction of tardive dyskinesia with second-generation antipsychotics appears unlikely to meet standards for cost-effectiveness.

Tardive dyskinesia: eliminated, forgotten, or overshadowed?

PURPOSE OF REVIEW

The present review focuses on atypical antipsychotics and tardive dyskinesia.

RECENT FINDINGS

We have known for many years that clozapine has a diminished risk of tardive dyskinesia compared with typical antipsychotics. The last decade has seen the introduction of a number of other atypical antipsychotics, allowing us to begin evaluating whether they too share this attribute. In addition, the opportunity to use these drugs as first-line treatment permits a more precise means of establishing risk. While longer-term data are required, the limited evidence available clearly indicates that the atypical antipsychotics have a decreased liability of tardive dyskinesia, approximately 1% compared with 5% for typical agents annually. Like clozapine, the other atypical antipsychotics also demonstrate antidyskinetic properties in individuals with preexisting tardive dyskinesia. The underlying mechanisms remain unclear, and without such information it is not possible to say what clinical conditions, if any, might diminish or even eliminate these advantages.

SUMMARY

An update is provided regarding the atypical antipsychotics and tardive dyskinesia. This information is critical in our decision-making regarding choice of antipsychotic and optimal use in the clinical setting.

Duration of therapy with metoclopramide: a prescription claims data study

PURPOSE

Metoclopramide-induced tardive dyskinesia is associated with cumulative drug exposure, which can result from prolonged use of the drug. We estimated therapy duration with metoclopramide, and measured the extent of therapy beyond the maximum time period of 12 weeks evaluated in the clinical trials and recommended in the label.

METHODS

Prescription claims for metoclopramide from 2002 to 2004 were extracted for participants residing throughout the US and contained within the Caremark pharmacy benefit manager (PBM) database. An episode of therapy was defined as one or a series of consecutive claims with no more than a 30-day lag between the dispensing date of a new claim and the ending date of the preceding claim. Episode duration was calculated by subtracting the start date from the end date for each episode.

RESULTS

During the study period, almost 80% of participants (total = 200 907) had only one episode of therapy. The length of the longest episode for most patients (85%) varied from 1 to 90 days, yet 15% of the patients appeared to have received prescriptions for metoclopramide for a period longer than 90 days. Cumulative therapy for longer than 90 days was recorded for almost 20% of the patients.

CONCLUSIONS

These results suggest that despite the known risk of tardive dyskinesia and the labeled recommendations on duration of metoclopramide use, many patients appear to use the drug for relatively long time periods beyond the labeled recommendations. Physicians should carefully consider the risk-benefit profile of the drug and, if possible, avoid increased risk of tardive dyskinesia due to prolonged exposure.