Tardive Dyskinesia with Antipsychotic Medication in Children and Adolescents: A Systematic Literature Review

BACKGROUND

Tardive dyskinesia (TD) is a persisting, and potentially irreversible, movement disorder associated with treatment with dopamine receptor antagonists. Few data are available on the risk of TD in children and adolescents treated with antipsychotic medication.

OBJECTIVE

To review the literature on incidence, risk factors, and treatment options for antipsychotic-associated TD in children and adolescents (aged < 18 years).

METHODS

Relevant articles were identified through a systematic search of Embase and Medline performed in January 2024. Methodological quality was assessed using the Newcastle-Ottawa Scale and Joanna Briggs Institute Critical Appraisal tools.

RESULTS

Thirteen studies were identified. The reported TD point prevalence was 5-20%, with higher rates in studies involving typical antipsychotics. Lower estimates (around 1%) emerged from analyses of clinical database data suggesting underdiagnosis in clinical practice. Risk factors included treatment with typical antipsychotics, higher doses, longer duration of exposure, older age, female gender, higher baseline Abnormal Involuntary Movements Scale (AIMS) scores, intellectual impairment, and perinatal complications.

CONCLUSION

Although relatively few cases have been reported in children and adolescents, TD remains a risk in this population. Individuals receiving antipsychotics should be monitored carefully for the emergence of abnormal movements. Other than dose reduction, discontinuation, or switch to a lower-risk antipsychotic, few interventions have demonstrated efficacy. The strongest evidence for pharmacological treatment is for VMAT-2 inhibitors (valbenazine and deutetrabenazine), but these drugs are not licensed for use in children. To reduce risk, antipsychotics should be prescribed only if necessary, at the minimum effective dose and for the minimum necessary duration.

Safety of prolonged use of metoclopramide and domperidone as treatment for chronic gastrointestinal dysmotility disorders in patients with systemic sclerosis

Background

Metoclopramide and domperidone are prokinetic agents commonly used to treat gastrointestinal dysmotility disorders. This study aimed to evaluate the safety and associated side effects of prolonged-use metoclopramide and domperidone as treatment for chronic gastrointestinal dysmotility disorders in patients with systemic sclerosis (SSc).

Methods

A quantitative observational survey was conducted by interview questionnaire in rheumatology outpatients at a tertiary teaching hospital in Riyadh, Saudi Arabia. The study included all patients aged 25-80 years diagnosed with SSc. All patients were on metoclopramide or domperidone for the treatment of chronic gastrointestinal dysmotility symptoms over at least 12 weeks.

Results

Eighteen eligible patients were included. Most study participants were diagnosed with SSc complicated by interstitial lung disease (n = 13; 72.2 %). The most frequently reported side effect that occurred while taking prokinetic drugs was shortness of breath (n = 12; 66.7 %). None of the participants reported experiencing depression, galactorrhea, or syncope. CNS side effects were reported in 5.6 %. There were no differences in side effects based on the type and dosage of prokinetic drug used.

Conclusions

Use of metoclopramide and domperidone for the treatment of chronic gastrointestinal dysmotility in SSc patients for 12 weeks or longer was not associated with any troublesome side effects. Further studies with more participants are needed to confirm our findings.

Botulinum toxin treatment in parkinsonism

Botulinum toxin (BoNT) was approved by the United States Food and Drug Administration (FDA) in 1989 for facial movement disorders and strabismus, but since that time its indications have been expanding beyond neurologic and ophthalmologic disorders. This article is a narrative review of the therapeutic use of BoNT in tremors, dystonia, sialorrhea, bladder and other autonomic symptoms, levodopa-induced dyskinesia and other problems occuring in the setting of parkinsonism. Though FDA approval is lacking for some of these indications, expert experiences have shown that BoNT is often beneficial in this group of patients.

Case report: Pallidal deep brain stimulation for treatment of tardive dystonia/dyskinesia secondary to chronic metoclopramide medication

Objectives

Tardive dystonia/dyskinesia (TDD) occurs as a side effect of anti-dopaminergic drugs, including metoclopramide, and is often refractory to medication. While pallidal deep brain stimulation (DBS) has become an accepted treatment for TDD secondary to neuroleptic medication, there is much less knowledge about its effects on metoclopramide-induced TDD.

Methods

We present the case of a woman with metoclopramide-induced TDD, whose symptoms were initially misjudged as "functional." After 8 years of ineffective medical treatments, she received bilateral implantation of quadripolar electrodes into the posteroventral lateral globus pallidus internus (GPi).

Results

GPi DBS led to significant symptom reduction [Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) motor score 24/44 at admission and 7/44 at discharge]. Chronic stimulation led to full recovery from TDD symptoms 9 years after surgery. The BFMDRS motor score decreased to 0.5 (98% improvement).

Discussion

Pallidal DBS may result in sustained improvement of TDD secondary to chronic metoclopramide intake in the long term.

International consensus validation of the POPI tool (Pediatrics: Omission of Prescriptions and Inappropriate prescriptions) to identify inappropriate prescribing in pediatrics

INTRODUCTION

While drug prescription should be based on established recommendations stemming from clinical trials but in pediatrics, many drugs are used without marketing authorization. Consequently recommendations are often based on clinical experience and the risk of inappropriate prescription (IP) is high. A tool for detecting IP in pediatrics-called POPI (Pediatrics: Omission of Prescriptions and Inappropriate prescriptions)-has been developed in France. However the relevance of its use at an international level is not known. Our aim has been to adapt POPI for a worldwide use.

MATERIAL AND METHOD

A two-round Delphi online questionnaire was completed and validated by international experts to identify consensual items. They were asked to rate the validity of each items taking into account the recommendations and practices in their countries. Only propositions obtaining a median score in the upper tertile with an agreement of more than 75% of the panel-for the first round-and 85%-for the second round-were retained.

RESULTS

Our panel included 11 pharmacists (55%) and 9 physicians (45%). The panelists came from 12 different countries: England, Belgium, Brazil, Canada, China, Ivory Coast, Ireland, Malaysia, Portugal, Switzerland, Turkey and Vietnam. At the end of the first round, of the 105 items of the original POPI tool, 80 items were retained including 16 items reworded and 25 items were deleted. In the second round, 14 experts participated in the study. This final international POPI tool is composed of 73 IP and omissions of prescriptions in the fields of neuropsychiatry, dermatology, infectiology, pneumology, gastroenterology, pain and fever.

DISCUSSION AND CONCLUSION

This study highlights international consensus on prescription practice in pediatrics. The use of this tool in everyday practice could reduce the risk of inappropriate prescription. The impact of the diffusion of POPI tool will be assessed in a prospective multicentric study.

Relating Substructures and Side Effects of Drugs with Chemical-chemical Interactions

Background:

Drugs are very important for human life because they can provide treatment, cure, prevention, or diagnosis of different diseases. However, they also cause side effects, which can increase the risks for humans and pharmaceuticals companies. It is essential to identify drug side effects in drug discovery. To date, lots of computational methods have been proposed to predict the side effects of drugs and most of them used the fact that similar drugs always have similar side effects. However, previous studies did not analyze which substructures are highly related to which kind of side effect.

Method:

In this study, we conducted a computational investigation. In this regard, we extracted a drug set for each side effect, which consisted of drugs having the side effect. Also, for each substructure, a set was constructed by picking up drugs owing such substructure. The relationship between one side effect and one substructure was evaluated based on linkages between drugs in their corresponding drug sets, resulting in an Es value. Then, the statistical significance of Es value was measured by a permutation test.

Results and Conclusion:

A number of highly related pairs of side effects and substructures were obtained and some were extensively analyzed to confirm the reliability of the results reported in this study.

Gastroparesis, metoclopramide, and tardive dyskinesia: Risk revisited

BACKGROUND

Metoclopramide is primarily a dopamine receptor antagonist, with 5HT₃ receptor antagonist and 5HT₄ receptor agonist activity, and used as an antiemetic and gastroprokinetic since almost 50 years. Regulatory authorities issued restrictions and recommendations regarding long-term use of the drug at oral doses exceeding 10 mg 3-4 times daily because of the risk for development of tardive dyskinesia. The aim of our study was to review mechanism(s) of action and pharmacokinetic-pharmacodynamic properties of metoclopramide, as well as the risk of metoclopramide-induced tardive dyskinesia, factors that may change drug exposure in humans, and to summarize the clinical context for appropriate use of the drug.

METHODS

A PubMed, Google Scholar, and Cross Reference search was done using the key words and combined searches: drug-drug interaction, gastroparesis, metoclopramide, natural history, pharmacokinetics, pharmacodynamics, drug-drug interaction, outcome, risk factors, tardive dyskinesia.

KEY RESULTS

Data show that the risk of tardive dyskinesia from metoclopramide is low, in the range of 0.1% per 1000 patient years. This is far below a previously estimated 1%-10% risk suggested in treatment guidelines by regulatory authorities. High-risk groups are elderly females, diabetics, patients with liver or kidney failure, and patients with concomitant antipsychotic drug therapy, which reduces the threshold for neurological complications.

CONCLUSIONS & INFERENCES

The risk of tardive dyskinesia due to metoclopramide is far below approximated numbers in treatment guidelines. This risk and the influence of known risk factors should be considered when starting a course of metoclopramide for treatment of gastroparesis.

Metoclopramide for the treatment of diabetic gastroparesis

Introduction: Gastroparesis is a chronic disorder of the stomach characterized by delayed gastric emptying without mechanical obstruction. Diabetes is the most commonly known cause of gastroparesis. Management of diabetic gastroparesis involves lifestyle modifications, glycemic control, pharmacological drugs, and for refractory cases surgical treatments. Metoclopramide remains the only drug approved by the Food and Drug Administration for diabetic gastroparesis. The aim of this article is to provide a concise review of the pharmacology, clinical efficacy and tolerability of metoclopramide. Areas covered: We searched PubMed using the key words 'metoclopramide', 'diabetic gastroparesis', and 'gastric emptying'. The relevant articles and their bibliography were reviewed. Metoclopramide acts on several different receptors; primarily as a dopamine receptor antagonist, both peripherally improving gastric emptying, and centrally resulting in an anti-emetic effect. Metoclopramide side effects, mostly related to its ability to cross the blood-brain barrier, include drowsiness, restlessness, hyperprolactinemia, and tardive dyskinesia (TD), a movement disorder that may be irreversible. Expert opinion: Metoclopramide carries a black box warning for use >12 weeks due to the risk of TD. However, gastroparesis patients experience chronic symptoms often requiring prolonged treatments. Physicians and patients look forward to FDA approval of new agents for gastroparesis with better efficacy and safety profile.

Association Between Drug Exposure and Occurrence of Parkinsonism in Korea: A Population-Based Case-Control Study

Background: Although drug-induced parkinsonism is reversible in most cases, some patients can suffer from persistent/recurrent symptoms. Therefore, prevention is the most efficient way to manage drug-induced parkinsonism. However, there is a paucity of studies exploring the relationship between parkinsonism and drug exposure. Objective: To examine the association between drug exposure and the risk of parkinsonism using Korean population-based data. Methods: We conducted a matched case-control study using the National Health Insurance Service-National Sample Cohort database. Cases and controls were defined as individuals with and without parkinsonism, respectively, between 2007 and 2013. Cases and controls were matched for sex, age group, income, type of insurance, and Charlson comorbidity index. Drug exposures, including propulsives, antipsychotics, and flunarizine, were identified at 1 year before the first date of parkinsonism and stratified by recency and cumulative dose. Conditional logistic regression was used to estimate odds ratios (ORs) and 95% CIs. Results: We identified 5496 cases and 5496 controls. ORs for current use group of propulsives, antipsychotics, and flunarizine compared with those of the never use group were 2.812 (95% CI = 2.466-3.206), 3.009 (95% CI = 1.667-5.431), and 4.950 (95% CI = 2.711-9.037), respectively. ORs were greater in those more recently exposed and those exposed to higher cumulative doses. Conclusion and Relevance: At the population level, use of propulsives, antipsychotics, and flunarizine had a significant association with the increased risk of parkinsonism, depending on recency and cumulative dose. Drugs associated with parkinsonism should be used with careful monitoring to prevent drug-induced parkinsonism.

Antipsychotic-induced tardive dyskinesia: update on epidemiology and management

PURPOSE OF REVIEW

To provide an update on the frequency of antipsychotic-induced tardive dyskinesia and its management in patients with schizophrenia spectrum disorders in studies published since the last systematic review in 2008.

RECENT FINDINGS

Recent data about antipsychotic-induced tardive dyskinesia in patients with schizophrenia underscore the superiority of newer generation antipsychotics (21%) over first-generation antipsychotics (30%) with respect to prevalence and incidence rates. Regarding recently tested management strategies, the new vesicular monoamine transporter 2 inhibitors valbenazine and deutetrabenazine have been found to be effective and may be considered as first-line pharmacotherapy for tardive dyskinesia. Owing to quality issues of randomized controlled trials and/or small sample sizes, limited and conflicting evidence remains for most treatment strategies.

SUMMARY

The reviewed literature reveals lower prevalence rates of antipsychotic-induced tardive dyskinesia in patients treated with newer generation compared with first-generation antipsychotics. The evidence of vesicular monoamine transporter 2 inhibitors as a first-line therapy for tardive dyskinesia is well supported by several controlled clinical trials.

Treatment of Tardive Dyskinesia: A General Overview with Focus on the Vesicular Monoamine Transporter 2 Inhibitors

Tardive dyskinesia (TD) encompasses the spectrum of iatrogenic hyperkinetic movement disorders following exposure to dopamine receptor-blocking agents (DRBAs). Despite the advent of atypical or second- and third-generation antipsychotics with a presumably lower risk of complications, TD remains a persistent and challenging problem. Prevention is the first step in mitigating the risk of TD, but early recognition, gradual withdrawal of offending medications, and appropriate treatment are also critical. As TD is often a persistent and troublesome disorder, specific antidyskinetic therapies are often needed for symptomatic relief. The vesicular monoamine transporter 2 (VMAT2) inhibitors, which include tetrabenazine, deutetrabenazine, and valbenazine, are considered the treatment of choice for most patients with TD. Deutetrabenazine-a deuterated version of tetrabenazine-and valbenazine, the purified parent product of one of the main tetrabenazine metabolites, are novel VMAT2 inhibitors and the only drugs to receive approval from the US FDA for the treatment of TD. VMAT2 inhibitors deplete presynaptic dopamine and reduce involuntary movements in many hyperkinetic movement disorders, particularly TD, Huntington disease, and Tourette syndrome. The active metabolites of the VMAT2 inhibitors have high affinity for VMAT2 and minimal off-target binding. Compared with tetrabenazine, deutetrabenazine and valbenazine have pharmacokinetic advantages that translate into less frequent dosing and better tolerability. However, no head-to-head studies have compared the various VMAT2 inhibitors. One of the major advantages of VMAT2 inhibitors over DRBAs, which are still being used by some clinicians in the treatment of some hyperkinetic disorders, including TD, is that they are not associated with the development of TD. We also briefly discuss other treatment options for TD, including amantadine, clonazepam, Gingko biloba, zolpidem, botulinum toxin, and deep brain stimulation. Treatment of TD and other drug-induced movement disorders must be individualized and based on the severity, phenomenology, potential side effects, and other factors discussed in this review.

Tardive dyskinesia risk with first- and second-generation antipsychotics in comparative randomized controlled trials: a meta-analysis

Tardive dyskinesia (TD) risk with D2/serotonin receptor antagonists or D2 receptor partial agonists (second-generation antipsychotics, SGAs) is considered significantly lower than with D2 antagonists (first-generation antipsychotics, FGAs). As some reports questioned this notion, we meta-analyzed randomized controlled studies (RCTs) to estimate the risk ratio (RR) and annualized rate ratio (RaR) of TD comparing SGAs vs. FGAs and SGAs vs. SGAs. Additionally, we calculated raw and annualized pooled TD rates for each antipsychotic. Data from 57 head-to-head RCTs, including 32 FGA and 86 SGA arms, were meta-analyzed, yielding 32 FGA-SGA pairs and 35 SGA-SGA pairs. The annualized TD incidence across FGA arms was 6.5% (95% CI: 5.3-7.8%) vs. 2.6% (95% CI: 2.0-3.1%) across SGA arms. TD risk and annualized rates were lower with SGAs vs. FGAs (RR=0.47, 95% CI: 0.39-0.57, p<0.0001, k=28; RaR=0.35, 95% CI: 0.28-0.45, p<0.0001, number-needed-to-treat, NNT=20). Meta-regression showed no FGA dose effect on FGA-SGA comparisons (Z=-1.03, p=0.30). FGA-SGA TD RaRs differed by SGA comparator (Q=21.8, df=7, p=0.003), with a significant advantage of olanzapine and aripiprazole over other non-clozapine SGAs in exploratory pairwise comparisons. SGA-SGA comparisons confirmed the olanzapine advantage vs. non-clozapine SGAs (RaR=0.66, 95% CI: 0.49-0.88, p=0.006, k=17, NNT=100). This meta-analysis confirms a clinically meaningfully lower TD risk with SGAs vs. FGAs, which is not driven by high dose FGA comparators, and documents significant differences with respect to this risk between individual SGAs.

Tardive dyskinesia: Epidemiology

The term tardive syndrome (TS) encompasses a few different phenomenologic conditions, some of which occur in isolation and others in association with each other. This, along with the unusual confound for a drug side effect, in which increased use of the drug improves the problem, and the need for most patients to continue taking the offending drug, makes understanding the epidemiology difficult and unreliable. While the change from the "first generation" to the "second generation" of antipsychotic drugs is generally believed to have reduced the incidence of TS, prospective research studies have not supported that contention. Published reports have found point prevalences of 13% with second generation antipsychotics and 32% with first, yet others have found no differences. One study found increasing rates of TS with a 68% prevalence by 25 years, while another found a decreased prevalence over time, due presumably to masking effects of the antipsychotic drugs. Regardless of the possible differences, it is clear that TS remains a significant and common problem associated with almost all antipsychotic drugs. There have also been scattered reports of TS caused by drugs not known to inhibit dopamine receptors. These are reviewed and were found to be often of dubious reliability.

Reported time to onset of neurological adverse drug reactions among different age and gender groups using metoclopramide: an analysis of the global database Vigibase®

PURPOSE

Despite FDA and EMA warnings of long-term use, little is known regarding the time to onset (TTO) of neurological adverse drug reactions (ADR) for metoclopramide. The aims of this study were, first, to evaluate whether neurological ADRs are more commonly reported for metoclopramide than for other medications, and second, to describe how time to onset of neurological ADRs differs by age and gender.

METHODS

All ADR reports with metoclopramide as the suspected/interacting drug were extracted from the WHOs Global ADR database Vigibase® between 1967 and May 2016. Cox proportional hazards models were fit using TTO of neurological ADRs as the outcome and age, gender, and type of ADR as predictors. Proportional Reporting Ratios (PRRs) for neurological ADRs were compared across age and gender. Lawyer reports were excluded in the analysis.

RESULTS

Over 47,000 ADR reports with metoclopramide were identified. Over one third (35.6%) of the reports came from lawyers. The majority of ADRs in general and neurological ADRs in specific occurred within the first 5 days of metoclopramide use (median 1 day). TTO increased with age. Neurological ADRs were reported two to four times as frequently for metoclopramide than for other drugs, with the highest PRRs observed in children (PRR = 4.24 for girls and 4.60 for boys).

CONCLUSIONS

Most adverse drug reactions occur within the first 5 days of treatment with metoclopramide. Patients requiring use of metoclopramide should be carefully monitored for neurological ADRs during the first days of treatment.

Prokinetics in the Management of Functional Gastrointestinal Disorders

PURPOSE OF REVIEW

The goal of this review is to review the current status of prokinetics and to place it in historical context. Impaired motility and thus propulsion have long been thought to play important roles in the pathogenesis of a number of gastrointestinal disorders including gastroesophageal reflux disease (GERD), gastroparesis, chronic idiopathic pseudo-obstruction, and constipation. Historically, disordered motility was also thought to contribute to a number of functional gastrointestinal disorders such as functional dyspepsia (FD) and irritable bowel syndrome (IBS).

RECENT FINDINGS

As we learn more of the pathophysiology of FD, IBS, GERD, constipation, and gastroparesis, the limitations of a therapeutic strategy based on the stimulation of motility (i.e., the use of a prokinetic) have become apparent and the disappointments of the past explained. The development of prokinetic drugs has also been hampered by the non-selective nature of many of the agents studied to date which resulted in some unexpected side effects. There is still an unmet need for an effective and safe prokinetic, but drug development in this area must be mindful of the challenges of the area and the need for selectivity for a given target receptor.

Tardive Dyskinesia Associated with Bupropion

Present report describes a 46 year old male patient with a diagnosis of major depression who developed tardive dyskinesia during bupropion therapy. Our patient had no history of neuroleptic use and his laboratory and neurologic examinations were normal. He had no family history of neurologic diseases. Although bupropion induced dyskinesia has been previously reported in the literature, it is rare and our case is the first case regarding tardive dyskinesia.

[Antipsychotic-induced tardive syndromes]

Tardive dyskinesia (TD) remains a relevant clinical problem despite the increasing use of new-generation antipsychotics. Antipsychotic-induced tardive syndromes are difficult to treat and have a low tendency of remission. Therefore, prophylaxis is of utmost importance, with the responsible use of antipsychotics as a prime desideratum. With respect to managing tardive dyskinesia, discontinuing the antipsychotic, if possible, albeit not backed up by unequivocal evidence, is still the main recommendation. If this is not possible, the switch to an antipsychotic with a lower TD risk is the next-preferred option. Other symptomatic treatments have been explored, but clinical trials have provided inhomogeneous results and only very few compounds are approved for the treatment of tardive dyskinesia. This manuscript summarizes the current evidence with respect to the phenomenology, course, prevention and treatment of tardive syndromes.

Commonly used gastrointestinal drugs

This chapter reviews the spectrum and mechanisms of neurologic adverse effects of commonly used gastrointestinal drugs including antiemetics, promotility drugs, laxatives, antimotility drugs, and drugs for acid-related disorders. The commonly used gastrointestinal drugs as a group are considered safe and are widely used. A range of neurologic complications are reported following use of various gastrointestinal drugs. Acute neurotoxicities, including transient akathisias, oculogyric crisis, delirium, seizures, and strokes, can develop after use of certain gastrointestinal medications, while disabling and pervasive tardive syndromes are described following long-term and often unsupervised use of phenothiazines, metoclopramide, and other drugs. In rare instances, some of the antiemetics can precipitate life-threatening extrapyramidal reactions, neuroleptic malignant syndrome, or serotonin syndrome. In contrast, concerns about the cardiovascular toxicity of drugs such as cisapride and tegaserod have been grave enough to lead to their withdrawal from many world markets. Awareness and recognition of the neurotoxicity of gastrointestinal drugs is essential to help weigh the benefit of their use against possible adverse effects, even if uncommon. Furthermore, as far as possible, drugs such as metoclopramide and others that can lead to tardive dyskinesias should be used for as short time as possible, with close clinical monitoring and patient education.

Loss of dopamine neuron terminals in antipsychotic-treated schizophrenia; relation to tardive dyskinesia

The in vivo labeling and brain imaging of dopamine transporters measure the density of dopamine neuron terminals in the human caudate/putamen. A review of such studies shows that the long-term use of antipsychotics had no major effect on the density of the dopamine terminals in individuals who had no tardive dyskinesia, but had reduced the density in those patients with tardive dyskinesia. In addition, the normal loss of dopamine terminals in healthy individuals was approximately 5% per decade. However, this rate of cell loss was apparently increased by approximately three-fold, to about 15% per decade, in schizophrenia patients using antipsychotics on a long-term basis, as measured by the in vivo imaging of the dopamine transporters in the dopamine neuron terminals. While an apparent reduction in dopamine transporters may result from reduced expression of the transporters secondary to antipsychotic treatment, the seemingly increased loss rate is consistent with the accumulation of antipsychotics in the neuromelanin of the substantia nigra, subsequent injury to the dopamine-containing neurons, and the development of extrapyramidal motor disturbances such as tardive dyskinesia or Parkinson's disease.

Haloperidol-induced striatal Nur77 expression in a non-human primate model of tardive dyskinesia

Tardive dyskinesia (TD) is a delayed and potentially irreversible motor complication arising in patients chronically exposed to antipsychotic drugs. As several modern (so-called atypical) antipsychotic drugs are common offenders, combined with the widening clinical indications for prescription as well as exposure of vulnerable individuals, TD will remain a significant drug-induced unwanted side effect. In addition, the pathophysiology of TD remains elusive and therapeutics are difficult. Based on rodent experiments, we have previously shown that the transcriptional factor Nur77 (also known as nerve growth factor inducible gene B or Nr4a1) is induced in the striatum following antipsychotic drug exposure as part of a long-term neuroadaptive process. To confirm this, we exposed adult capuchin (Cebus apella) monkeys to prolonged treatments with haloperidol (median 18.5 months, N = 11) or clozapine (median 6 months, N = 6). Six untreated animals were used as controls. Five haloperidol-treated animals developed mild TD movements similar to those found in humans. No TD was observed in the clozapine group. Postmortem analysis of Nur77 expression measured by in situ hybridization revealed a stark contrast between the two drugs, as Nur77 mRNA levels in the caudate-putamen were strongly upregulated in animals exposed to haloperidol but were spared following clozapine treatment. Interestingly, within the haloperidol-treated group, TD-free animals showed higher Nur77 expression in putamen subterritories compared with dyskinetic animals. This suggests that Nur77 expression might be associated with a reduced risk of TD in this experimental model and could provide a novel target for drug intervention.

Treatment of neurolept-induced tardive dyskinesia

Tardive dyskinesia (TDK) includes orobuccolingual movements and "piano-playing" movements of the limbs. It is a movement disorder of delayed onset that can occur in the setting of neuroleptic treatment as well as in other diseases and following treatment with other drugs. The specific pathophysiology resulting in TDK is still not completely understood but possible mechanisms include postsynaptic dopamine receptor hypersensitivity, abnormalities of striatal gamma-aminobutyric acid (GABA) neurons, and degeneration of striatal cholinergic interneurons. More recently, the theory of synaptic plasticity has been proposed. Considering these proposed mechanisms of disease, therapeutic interventions have attempted to manipulate dopamine, GABA, acetylcholine, norepinephrine and serotonin pathways and receptors. The data for the effectiveness of each class of drugs and the side effects were considered in turn.

Beneficial effects of the sigma-1 agonist fluvoxamine for tardive dyskinesia in patients with postpsychotic depressive disorder of schizophrenia: report of 5 cases

OBJECTIVE

Tardive dyskinesia (TD) is characterized by involuntary, repetitive, purposeless movements that can affect different parts of the body. Tardive dyskinesia is a well-known side effect of conventional antipsychotics and commonly occurs after several years of treatment. The effective treatment of TD is unclear. Recently, the sigma-1 receptor agonist fluvoxamine was reported to be beneficial for hyperkinetic movement disorders.

METHOD

We report 5 cases with postpsychotic depressive disorder of schizophrenia and TD. All patients were given fluvoxamine 100 mg/d, and after the second week the dosage of fluvoxamine was increased to 200 mg/d. At the fourth week, patients were assessed in terms of TD and postpsychotic depressive disorder of schizophrenia.

RESULTS

Fluvoxamine was found to be beneficial for TD and postpsychotic depressive disorder of schizophrenia in all patients by the fourth week.

CONCLUSIONS

Recently, the sigma-1 receptor agonist fluvoxamine has been considered beneficial for various neuropsychiatric disorders. However, data about the effects of fluvoxamine on hyperkinetic movement disorders are limited. In this report, we attempted to demonstrate the beneficial effects of fluvoxamine on TD, and we suggest that the mechanism of action might be due to sigma-1 agonism. Further detailed, double-blind studies should clarify the potential use of fluvoxamine in the treatment of hyperkinetic movement disorders.

Sensory trick with metoclopramide-associated tardive tremor

Tardive tremor is a 3-5 Hz bilateral resting and action tremor, associated with the use of dopamine receptor blocking drugs, accompanied by other tardive movement disorders and responsive to tetrabenazine or clozapine. We describe a case of a sensory trick associated with tardive tremor which raises important points about semiology and management. First, the presence of a sensory trick with tardive limb tremor suggests that the disorder may be a form of dystonia. Second, further study of osteopathic manipulative therapy for treatment of dystonia or tardive tremor is supported by a symptomatic response observed in our case.

Tardive dyskinesia after short-term treatment with oral metoclopramide in an adolescent

CASE

The objective of this case report is to report the development of tardive dyskinesia in an African-American adolescent male after short-term treatment with metoclopramide 10 mg orally three times daily secondary to delayed gastric emptying. The patient developed symptoms of tardive dyskinesia after 2 days of therapy with metoclopramide. Metoclopramide was discontinued and diphenhydramine 50 mg was initially administered intravenously followed with 25 mg orally every 4 hours as needed. While there are case reports of drug-induced tardive dyskinesia after intravenous administration of metoclopramide, this is to our knowledge the first report of tardive dyskinesia after short-term treatment with oral metoclopramide in an adolescent.

CONCLUSION

Awareness of the risk of development of this adverse effect even with short-term treatment with metoclopramide and in younger patients is important.

Tetrabenazine for the treatment of chorea and other hyperkinetic movement disorders

Tetrabenazine (TBZ; Xenazine) is a potent, selective, reversible depletor of monoamines from nerve terminals. TBZ inhibits the vesicular monoamine transporter type 2 which, in humans, is expressed nearly exclusively in the brain. TBZ is rapidly metabolized in the liver by carbonyl reductase to stereoisomers of hydrotetrabenazine, some of which are potent inhibitors of vesicular monoamine transporter type 2. Initially developed in the 1950s for schizophrenia, since the 1970s several publications have reported on the efficacy of TBZ in the treatment of various hyperkinetic movement disorders. Although quite effective in controlling the involuntary movements, there were considerable inter-individual differences in the optimal dose, defined as the dose judged by the investigator to provide the greatest efficacy with minimal or tolerable adverse events. This variability is in part owing to differences in severity and mechanism of the target symptoms and to variable activity of the enzyme carbonyl reductase that metabolizes TBZ to its active metabolites. Dose-limiting adverse events, consisting mainly of sedation, parkinsonism, akathisia and depression, are usually rapidly reversible upon dosage reduction. In addition to its established antichorea efficacy in Huntington's disease, the drug has been reported to also be effective in a variety of other hyperkinetic movement disorders, including tardive dyskinesia and tics associated with Tourette's syndrome.

Drug-induced parkinsonism

Drug-induced parkinsonism (DIP) is the second-most-common etiology of parkinsonism in the elderly after Parkinson's disease (PD). Many patients with DIP may be misdiagnosed with PD because the clinical features of these two conditions are indistinguishable. Moreover, neurological deficits in patients with DIP may be severe enough to affect daily activities and may persist for long periods of time after the cessation of drug taking. In addition to typical antipsychotics, DIP may be caused by gastrointestinal prokinetics, calcium channel blockers, atypical antipsychotics, and antiepileptic drugs. The clinical manifestations of DIP are classically described as bilateral and symmetric parkinsonism without tremor at rest. However, about half of DIP patients show asymmetrical parkinsonism and tremor at rest, making it difficult to differentiate DIP from PD. The pathophysiology of DIP is related to drug-induced changes in the basal ganglia motor circuit secondary to dopaminergic receptor blockade. Since these effects are limited to postsynaptic dopaminergic receptors, it is expected that presynaptic dopaminergic neurons in the striatum will be intact. Dopamine transporter (DAT) imaging is useful for diagnosing presynaptic parkinsonism. DAT uptake in the striatum is significantly decreased even in the early stage of PD, and this characteristic may help in differentiating PD from DIP. DIP may have a significant and longstanding effect on patients' daily lives, and so physicians should be cautious when prescribing dopaminergic receptor blockers and should monitor patients' neurological signs, especially for parkinsonism and other movement disorders.

Cisapride improves enteral tolerance in pediatric short-bowel syndrome with dysmotility

BACKGROUND AND OBJECTIVES

Gastrointestinal dysmotility is common in pediatric short-bowel syndrome, leading to prolonged parenteral nutrition dependence. There is limited literature regarding the safety and efficacy of cisapride for this indication. The aim of the study was to describe the safety and efficacy of cisapride for enteral intolerance in pediatric short-bowel syndrome.

METHODS

Open-labeled pilot study in a limited access program for cisapride. Indications were short-bowel syndrome with underlying dysmotility and difficulty advancing enteral feeds despite standard therapies and without evidence of anatomic obstruction. Patients received cisapride 0.1 to 0.2 mg/kg per dose for 3 to 4 doses per day. We collected electrocardiogram, nutrition, and anthropometric data prospectively at study visits.

RESULTS

Ten patients with mean (SD) age of 30.3 (30.5) months were enrolled in our multidisciplinary pediatric intestinal rehabilitation program. Median (interquartile range [IQR]) duration of follow-up was 8.7 (3.1-14.3) months. Median (IQR) residual bowel length was 102 (85-130) cm. Median (IQR) citrulline level was 14.5 (10.5-31.3) μmol/L. Diagnoses included isolated gastroschisis (n = 3), gastroschisis with intestinal atresia (n = 4), necrotizing enterocolitis (n = 2), and long-segment Hirschsprung disease (n = 1). Six subjects had at least 1 prior bowel-lengthening procedure. Median (IQR) change in percentage enteral energy intake was 19.9% (15.4%-29.8%) during follow-up (P = 0.01). Seven patients improved in enteral tolerance during treatment and 2 were weaned completely from parenteral nutrition. Complications during therapy were prolonged corrected QT interval (n = 2), gastrointestinal bleeding (n = 2), D-lactic acidosis (n = 1), and death due to presumed sepsis (n = 1). Longitudinal analysis (general estimating equation model) showed a strong positive association between cisapride duration and improved enteral tolerance. Mean percentage of enteral intake increased by 2.9% for every month of cisapride treatment (P < 0.0001).

CONCLUSIONS

Cisapride is a potentially useful therapy in patients with pediatric short-bowel syndrome with gastrointestinal dysmotility. We observed modest improvement in feeding tolerance where prior treatments failed; however, patients treated with cisapride require careful cardiac monitoring because corrected QT prolongation occurred in 20% of our cohort.

Epidemiology of tardive dyskinesia before and during the era of modern antipsychotic drugs

Late or tardive dyskinesias/dystonias (TD), contrary to expectation, have not disappeared with the use of expensive, modern antipsychotic drugs (APDs). Risk appears to be substantially lower than with older neuroleptics, and there is sparing of most acute movement disorders traditionally associated with APD treatment. However, risks of TD with modern APDs have been reduced much less than expected, by perhaps two- to threefold or even less, with substantial risks in the elderly. Major challenges in assessing prevalence or, preferably, incidence of TD arise from prolonged and erratic past exposure to various APDs, relatively recent use of modern APDs, and the occurrence of spontaneous movement disorders (about 5% and more in the elderly). TD risks associated with modern APDs may be similar to some older neuroleptics, especially those of low-moderate potency. Risperidone (and its active metabolite paliperidone), at high doses, may carry unusually high TD risk, whereas TD risk is low with clozapine, and perhaps quetiapine and aripiprazole. Optimistic expectations for the efficacy and neurological safety of modern APDs have encouraged their wide use in many conditions, sometimes off-label or in combinations, with little research support, increasing the chance of a higher prevalence of TD, especially at older ages. Measures to limit TD risk include: (1) critical, objective indications for APD use; (2) long-term use only for compelling or research-supported indications, primarily chronic psychotic illness that worsens when APD is slowly discontinued; (3) avoiding off-label indications; (4) using alternative treatments when APD treatment is elective, or early dyskinesia is identified; (5) using low but effective doses of single APDs, especially in the elderly; and (6) regular and specific examination for early TD.

Tardive dyskinesia and other movement disorders secondary to aripiprazole

The objective of this report is to draw attention to tardive dyskinesia (TD) caused by aripiprazole, a third generation antipsychotic. TD has been traditionally attributed to typical (first-generation) antipsychotics, but other dopamine receptor blocking drugs and atypical (second- and third-generation) neuroleptics are emerging as an important cause of TD. We reviewed the medical records of patients with TD seen at the Baylor College of Medicine Movement Disorders Clinic between 2002 and 2010 to identify patients with TD associated with aripiprazole. Among 236 patients with TD seen over the specified period, 8 (3.4%) were found to have aripiprazole-associated TD. In 5 patients, TD occurred after exclusive exposure to aripiprazole. The mean age at onset was 55.8 ± 14.8 years with a female predominance. The average duration of treatment with aripiprazole was 18.4 ± 26.4 months. Oro-bucco-lingual stereotypy was seen in all patients. In most patients, TD did not spontaneously improve after stopping aripiprazole. Of the 5 patients treated with tetrabenazine, 4 improved during follow-up. Although aripiprazole, a third generation antipsychotic, has been promoted to have a low risk of TD, the drug accounts for about 3.5% of patients with TD evaluated in a movement disorders clinic. This largest reported series draws attention to the growing incidence of TD and other drug-induced movement disorders associated with "atypical antipsychotics."

A biopsychosocial approach to improving quality of life in tardive dystonia

Tardive dystonia is a potential side effect of antipsychotic medications and certain other dopamine antagonists. It is characterized by sustained muscle contractions that lead to abnormal postures and movements. It is generally a permanent side effect that has a significant impact on a patient's physical, psychological, and social well-being, decreasing overall quality of life. The authors present the case of a patient with severe tardive dystonia due to metoclopramide that illustrates the profound physical, psychological, and social impact of this condition. It is important for clinicians to be knowledgeable about tardive dystonia so that they can take active steps to prevent its development and have a positive impact on its prognosis when it does develop by recognizing the condition early. Treatment of tardive dystonia should follow a biopsychosocial approach that combines an array of treatment modalities, depending on the individual presentation. Incorporating a quality of life questionnaire specific to dystonia into clinical practice can help clinicians tailor care to the needs of the individual patient.

Tardive dyskinesia and withdrawal emergent syndrome in children

Tardive dyskinesia (TD) is a well-recognized and sometimes permanent adverse effect of treatment with dopamine receptor-blocking drugs (DRBDs), also referred to as neuroleptics. This iatrogenic disorder has been well characterized in adults, but not extensively studied in children. Withdrawal emergent syndrome (WES) is another pediatric movement disorder related to the use of DRBDs. TD and WES are among the most feared adverse effects of DRBD treatment, and have important medical and legal implications. We review published studies of children under the age of 18 years who were exposed to DRBD to determine the clinical spectrum and estimate the possible prevalence of TD and WES. We particularly wish to draw attention to the phenomenology, clinical course and treatment of these childhood-onset disorders. Although avoiding DRBDs is the best strategy for minimizing the risk of TD and WES, physicians who evaluate children exposed to DRBDs must be vigilant and recognize the early symptoms and signs of these syndromes to provide appropriate clinical management.

Identification of novel metoclopramide metabolites in humans: in vitro and in vivo studies

Metoclopramide (MCP) is frequently used to treat gastroparesis. Previous studies have documented MCP metabolism, but systematic structural identification of metabolites has not been performed. The aim of this study was to better understand MCP metabolism in humans. For examination of in vivo metabolism, a single oral 20-mg MCP dose was administered to eight healthy male volunteers, followed by complete urine collection over 24 h. In vitro incubations were performed in human liver microsomes (HLM) to characterize metabolism via cytochromes P450 and UDP-glucuronosyltransferases and in human liver cytosol for metabolism via sulfotransferases. Urine and subcellular incubations were analyzed for MCP metabolites on a mass spectrometer with accurate mass measurement capability. Five MCP metabolites were detected in vivo, and five additional metabolites were detected in vitro. The five metabolites of MCP identified both in vitro and in vivo were an N-O-glucuronide (M1), an N-sulfate (M2), a des-ethyl metabolite (M3), a hydroxylated metabolite (M4), and an oxidative deaminated metabolite (M5). To our knowledge, metabolites M1 and M4 have not been reported previously. M2 urinary levels varied 22-fold and M3 levels varied 16-fold among eight subjects. In vitro studies in HLM revealed the following additional metabolites: two ether glucuronides (M6 and M8), possibly on the phenyl ring after oxidation, an N-glucuronide (M7), a carbamic acid (M9), and a nitro metabolite (M10). Metabolites M6 to M10 have not been reported previously. In conclusion, this study describes the identification of MCP metabolites in vivo and in vitro in humans.

Crossing the quality chasm in neonatal-perinatal medicine

The "Quality Chasm" exists in neonatal intensive care. Despite years of clinical research in neonatology, therapies continue to be underused, overused, or misused. A key concept in crossing the quality chasm is system redesign. The unpredictability of human factors and the dynamic complexity of the neonatal ICU are not amenable to rigid reductionist control and redesign. Change is best accomplished in this complex adaptive system by use of simple rules: (1) general direction pointing, (2) prohibitions, (3) resource or permission providing. These rules create conditions for purposeful self-organizing behavior, allowing widespread natural experimentation, all focused on generating the desired outcome.

Effectiveness of an aspiration risk-reduction protocol

BACKGROUND

Aspiration of gastric contents is a serious problem in critically ill, mechanically ventilated patients receiving tube feedings.

OBJECTIVES

The purpose of this study was to evaluate the effectiveness of a three-pronged intervention to reduce aspiration risk in a group of critically ill, mechanically ventilated patients receiving tube feedings.

METHODS

A two-group quasi-experimental design was used to compare outcomes of a usual care group (December 2002-September 2004) with those of an Aspiration Risk-Reduction Protocol (ARRP) group (January 2007-April 2008). The incidence of aspiration and pneumonia was compared between the usual care group (n = 329) and the ARRP group (n = 145). The ARRP had three components: maintaining head-of-bed elevation at 30 degrees or higher, unless contraindicated; inserting feeding tubes into distal small bowel, when indicated; and using an algorithmic approach for high gastric residual volumes.

RESULTS

Two of the three ARRP components were implemented successfully. Almost 90% of the ARRP group had mean head-of-bed elevations of 30 degrees or higher as compared to 38% in the usual care group. Almost three fourths of the ARRP group had feeding tubes placed in the small bowel as compared with less than 50% in the usual care group. Only three patients met the criteria for the high gastric residual volume algorithm. Aspiration was much lower in the ARRP group than that in the usual care group (39% vs. 88%, respectively). Similarly, pneumonia was much lower in the ARRP group than that in the usual care group (19% vs. 48%, respectively).

DISCUSSION

Findings from this study suggest that a combination of a head-of-bed position elevated to at least 30 degrees and use of a small-bowel feeding site can reduce the incidence of aspiration and aspiration-related pneumonia dramatically in critically ill, tube-fed patients.

Stomach dysfunction in diabetes mellitus: emerging technology and pharmacology

Gastroparesis and other types of gastric dysfunction result in substantial morbidity in diabetes patients. The pathophysiology of these disorders is incompletely understood. This article reviews techniques applicable to the assessment of gastric function in diabetes patients, including the measurement of emptying, accommodation, and contractility. Available treatment options are also reviewed, including novel yet unapproved serotonin 5-HT(4) agonist pharmacological treatments, as well as the role of endoscopic, surgical, and device treatments of gastroparesis.

Review article: metoclopramide and tardive dyskinesia

BACKGROUND

Metoclopramide is a dopamine receptor antagonist which has been used for treatment of a variety of gastrointestinal symptoms over the last thirty years. In 2009, the FDA issued a black box warning regarding long-term or high-dose use of this medication because of the risk of developing tardive dyskinesia.

AIMS

To review the mechanism of action and pharmacokinetic properties of metoclopramide, the risk of metoclopramide-induced tardive dyskinesia, potential mechanisms that may alter and to summarize the clinical context for appropriate use of the drug.

METHODS

We conducted a PubMed search using the following key words and combined searches: metoclopramide, neuroleptics, tardive dyskinesia, incidence, prevalence, dopamine, receptors, pharmacokinetic, pharmacology, pharmacogenetics, DRD3 Ser9Gly polymorphism, cytochrome P450, p-glycoprotein, risk factors, gastroparesis, outcome, natural history.

RESULTS

Available data show that risk of tardive dyskinesia from metoclopramide use is likely to be <1%, much less than the estimated 1-10% risk previously suggested in national guidelines. Tardive dyskinesia may represent an idiosyncratic response to metoclopramide; pharmacogenetics affect pharmacokinetic and dopamine receptor pharmacodynamics in response to neuroleptic agents that cause similar neurological complications.

CONCLUSION

Community prevalence and pharmacogenetic mechanisms involved in metoclopramide-induced tardive dyskinesia require further study to define the benefit-risk ratio more clearly.

Metoclopramide in the treatment of diabetic gastroparesis

Gastroparesis is a chronic disorder that affects a significant subset of the population. Diabetes mellitus is a risk factor for the development of gastroparesis. Currently, metoclopramide is the only US FDA-approved medication for the treatment of gastroparesis. However, the FDA recently placed a black-box warning on metoclopramide because of the risk of related side effects, including tardive dyskinesia, the incidence of which has been cited to be as high as 15% in the literature. This review will investigate the mechanisms by which metoclopramide improves the symptoms of gastroparesis and will focus on the evidence of clinical efficacy supporting metoclopramide use in gastroparesis. Finally, we seek to document the true complication risk from metoclopramide, especially tardive dyskinesia, by reviewing the available evidence in the literature. Potential strategies to mitigate the risk of complications from metoclopramide will also be discussed.

Migraine. Treating acute migraine in the emergency department

The management of acute migraine in the emergency department presents a therapeutic challenge for physicians, who need to provide adequate pain relief while minimizing adverse events and relapses. New research suggests that phenothiazines are effective drug therapies for acute migraine, highlighting their potential use as first-line treatments for acute migraine in the hospital setting.