Tardive Dyskinesia Risks and Metoclopramide Use Before and After U.S. Market Withdrawal of Cisapride

Prokinetics-safety and efficacy: The European Society of Neurogastroenterology and Motility/The American Neurogastroenterology and Motility Society expert review

BACKGROUND

Prokinetics are a class of pharmacological drugs designed to improve gastrointestinal (GI) motility, either regionally or across the whole gut. Each drug has its merits and drawbacks, and based on current evidence as high-quality studies are limited, we have no clear recommendation on one class or other. However, there remains a large unmet need for both regionally selective and/or globally acting prokinetic drugs that work primarily intraluminally and are safe and without systemic side effects.

PURPOSE

Here, we describe the strengths and weaknesses of six classes of prokinetic drugs, including their pharmacokinetic properties, efficacy, safety and tolerability and potential indications.

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.

Metoclopramide nasal spray for management of symptoms of acute and recurrent diabetic gastroparesis in adults

Introduction: Gastroparesis (GP) is characterized by delayed gastric emptying in the absence of mechanical obstruction. About 75% of GP patients are females. Diabetes and idiopathic are the two commonest etiologies of GP. Up to two-thirds of the GP patients do not have significant symptom responses to medical therapies, and there is a paucity of available oral prokinetic agents with only one medication approved by the U.S. Food and Drug Administration (FDA) for this indication. The oral and parenteral formulations of metoclopramide were FDA approved in 1979 to treat symptoms of acute and recurrent diabetic GP. Now, more than 40 years later, a nasal preparation of metoclopramide (Gimoti^TM) was approved in June 2020 for the same indication.Areas covered: PubMed search using the keywords 'nasal metoclopramide' and 'diabetic gastroparesis.' This article aims to provide a concise review of the pharmacology, clinical efficacy, and tolerability of nasal metoclopramide.Expert opinion: The nasal formulation can be systemically absorbed without relying on the passage through a poorly emptying stomach, thus assuring the delivery of a therapeutic dose of metoclopramide, even during episodes of vomiting. Hence, metoclopramide nasal spray has the potential to be used during an acute flare, potentially avoiding hospitalizations.

Influence of Cation Transporters (OCTs and MATEs) on the Renal and Hepatobiliary Disposition of [11C]Metoclopramide in Mice

PURPOSE

To investigate the role of cation transporters (OCTs, MATEs) in the renal and hepatic disposition of the radiolabeled antiemetic drug [11C]metoclopramide in mice with PET.

METHODS

PET was performed in wild-type mice after administration of an intravenous microdose (<1 μg) of [11C]metoclopramide without and with co-administration of either unlabeled metoclopramide (5 or 10 mg/kg) or the prototypical cation transporter inhibitors cimetidine (150 mg/kg) or sulpiride (25 mg/kg). [11C]Metoclopramide PET was also performed in wild-type and Slc22a1/2(-/-) mice. Radiolabeled metabolites were measured at 15 min after radiotracer injection and PET data were corrected for radiolabeled metabolites.

RESULTS

[11C]Metoclopramide was highly metabolized and [11C]metoclopramide-derived radioactivity was excreted into the urine. The different investigated treatments decreased (~2.5-fold) the uptake of [11C]metoclopramide from plasma into the kidney and liver, inhibited metabolism and decreased (up to 3.8-fold) urinary excretion, which resulted in increased plasma concentrations of [11C]metoclopramide. Kidney and liver uptake were moderately (~1.3-fold) reduced in Slc22a1/2(-/-) mice.

CONCLUSIONS

Our results suggest a contribution of OCT1/2 to the kidney and liver uptake and of MATEs to the urinary excretion of [11C]metoclopramide in mice. Cation transporters may contribute, next to variability in the activity of metabolizing enzymes, to variability in metoclopramide pharmacokinetics and side effects.

Esophageal and Gastric Motility Disorders in the Elderly

The elderly are particularly prone to developing upper gastrointestinal disturbances. Changes are due to the aging process, diabetes, cardiovascular risk factors, and neurologic issues. Medications used to treat these underlying conditions can cause gastrointestinal symptoms. Dysphagia is common and can be oropharyngeal and/or esophageal. Gastroparesis is due to either medications such opiates, or due to neurologic sequala of diabetes, cerebrovascular accidents, or neurologic diseases such as Parkinson's disease. Given limitations in many commonly used prokinetics with a wide range of side effect profiles including neurologic and cardiac, the focus of treatment should be on symptom management with dietary changes.

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.

Cystic Fibrosis and gastroesophageal reflux disease

Gastroesophageal reflux is common in children and adults with cystic fibrosis (CF). Pathological gastroesophageal reflux disease (GERD) is also frequent in patients of all ages with CF. This article reviews the pathophysiology, diagnostic work-up, management options, complications, and future directions in the evaluation and management of GERD - unique to and pertinent for - patients with CF in particular.

Gastroesophageal Reflux Disease and Aerodigestive Disorders

This relationship between gastroesophageal reflux and airway disorders is complex, possibly bidirectional, and not clearly defined. The tools used to investigate gastroesophageal reflux are mostly informative about involvement of gastroesophageal reflux within the gastrointestinal tract, although they are often utilized to study the relationship between gastroesophageal reflux and airway issues with are suspected to occur in relation to reflux. These modalities often lack specificity for reflux-related airway disorders. Co-incidence of gastroesophageal reflux and airway disorders does not necessarily infer causality. While much of our focus has been on managing acidity, controlling refluxate is an area that has not been traditionally aggressively pursued. Our management approach is based on some of the evidence presented, but also often from a lack of adequate study to provide further guidance.

From Harmful Treatment to Secondary Gain: Adverse Event Reporting in Dyspepsia and Gastroparesis

INTRODUCTION

Medical management of gastroparesis and functional dyspepsia remains difficult with several recent trials showing limited or no benefit. If treatment comes with only marginal improvements, concerns about adverse events become more relevant. We therefore examined the type and outcomes of side effects submitted to a public repository.

METHODS

We searched the Federal Adverse Event Reporting System for reports associated with the treatment of dyspepsia or gastroparesis. Demographic data, medications used and implicated, side effects, and outcomes were abstracted for the years 2004-2015.

RESULTS

Acid-suppressive agents and prokinetics were the most commonly listed medications with a stronger emphasis on prokinetics in gastroparesis. Submissions related to metoclopramide by far exceeded reports about other agents and mostly described tardive dyskinesia or other neurological concerns. They peaked around 2012, driven by submissions through legal workers. Most reports about metoclopramide described short-term use to prevent or treat nausea and vomiting. Concerns about acid-suppressive medications increased over time and spanned a wide spectrum of potential problems, including osteoporosis, worsening renal function, or cardiac events.

CONCLUSION

Despite biasing factors, such as pending legal action, the voluntary repository of adverse events provides insight into current medical practice and its associated risk. Knowing about common and uncommon, but potentially serious risks may enable patients and providers to decide on effective and safe management strategies.

Systematic review and meta-analysis: Gastric electrical stimulation for gastroparesis

BACKGROUND

Controlled trials of gastric electrical stimulation (GES) for gastroparesis reported no significant improvement in symptoms, while open label studies suggested substantial clinical benefits.

AIM

To determine if GES is effective in reducing symptoms in patients with gastroparesis.

METHODS

We searched PubMed and Embase for articles published in English (1990-2014) using "gastroparesis" as a search term restricted to "clinical trial". We included studies describing repeated patient-based symptom ratings before and during standardized treatments of at least one week duration.

RESULTS

Five studies randomly allocated patients to periods with or without GES. Total symptom severity (TSS) scores did not differ between these periods (0.17 [95% confidence interval: -0.06 to 0.4]; P=0.15). However, sixteen open label studies of GES showed a significant TSS decrease (2.68 [2.04-3.32]; Q=39.0; P<0.001). Other treatment modalities similarly improved TSS by 1.97 [1.5-2.44] for medical therapy (MED), by 1.52 [0.9-2.15] for placebo arms (PLA), and by 2.32 [1.56-3.06] for botulinum toxin (BTx). There were significant differences in baseline TSS ratings among these studies (GES: 6.28 [6.28-7.42]; MED: 4.76 [4.09-5.42]; PLA: 4.59 [3.77-5.42]; BTx: 6.02 [5.3-6.74]; Q=35.1; P<0.001). Meta-regression analysis showed these baseline differences to significantly impact TSS ratings during treatment (Q=71.8; P<0.001).

CONCLUSION

Independent of the treatment modality, baseline symptom severity impacts treatment results in gastroparesis. Considering the skewed population with refractory symptoms, regression to the mean likely contributes to the substantial discrepancies between the reported results of controlled and open label GES studies, raising questions about the use of GES outside of defined clinical trials.

Current and Emerging Medical Therapies for Gastroparesis

OPINION STATEMENT

Gastroparesis likely involves various pathophysiological disorders and is increasingly prevalent as complications of surgeries, medications, and chronic diabetes. Key to diagnosis is evidence of delayed gastric emptying, generally based on standardized scintigraphy, and ruling out distal obstruction or other dysmotilities. Initial medical management includes reviewing potentially exacerbating medications and ruling out other reversible causes, achieving tighter glucose control in diabetics, and implementing dietary and lifestyle changes. While current available medications are limited, symptomatic control is aimed at improving gastric emptying, alleviating nausea and vomiting, and treating associated abdominal pain. Other potential therapies are aimed at reducing acid production, improving gastric accommodation or pyloric dysfunction, and treating bacterial overgrowth. Future studies should be aimed toward identification of subpopulations of gastroparetics who are better responders to the various medications based on differences in underlying pathophysiology and adopting standardized study end point measures that may allow for comparisons across trials. This chapter will review current treatment options, upcoming promising medications, and some of the hurdles in advancing the field forward.

Drug-drug interactions in pharmacologic management of gastroparesis

BACKGROUND

Gastroparesis is a disorder characterized by delayed gastric emptying due to chronic abnormal gastric motility. The treatment of the disease often entails the co-administration of several classes of pharmacological agents. These agents may be metabolized via the same pathway. Inhibition or induction of a shared metabolic pathway leads to change in the systemic levels of prescribed drugs, possibly leading to undesired clinical outcomes.

PURPOSE

This review discusses different pharmacological treatment for gastroparesis patients and describes the potential for drug-drug interactions (DDIs) in some of the combinations that are currently used. Prokinetic agents such as metoclopramide and domperidone are the cornerstone in treatment of gastroparesis. Antiemetic agents such as promethazine and ondansetron are frequently administered to gastroparesis patients to reduce nausea and vomiting. Gastroparesis is prevalent in diabetic patients and therefore antidiabetic agents are also prescribed. Many of these co-administered drugs are metabolized via common drug metabolizing enzymes and this can trigger potential DDIs. The scientific literature was reviewed from the years 1975-2014 for original research articles and reviews that evaluated DDIs in gastroparesis. Many commonly prescribed combinations were predicted to cause potential DDIs in gastroparesis patients. This review will help inform about potential hazardous combinations. This information will hopefully lead to less adverse effects and more successful gastroparesis management.

Use and Safety of Erythromycin and Metoclopramide in Hospitalized Infants

OBJECTIVE

Prokinetic medications are used in premature infants to promote motility and decrease time to full enteral feeding. Erythromycin and metoclopramide are the most commonly used prokinetic medications in the neonatal intensive care unit (NICU), but their safety profile is not well defined.

METHODS

We conducted a large retrospective cohort study using data from 348 NICUs managed by the Pediatrix Medical Group. All of the infants exposed to ≥1 dose of erythromycin, metoclopramide, or both, from a cohort of 8,87,910 infants discharged between 1997 and 2012 were included. We collected laboratory and clinical information while infants were exposed to erythromycin or metoclopramide and described the frequency of laboratory abnormalities and clinical adverse events (AEs).

RESULTS

Metoclopramide use increased from 1997 to 2005 and decreased from 2005 to 2012, whereas erythromycin use remained stable. Erythromycin use was most often associated with a diagnosis of feeding problem (40%), whereas metoclopramide was most often associated with a diagnosis of gastroesophageal reflux (59%). The most common laboratory AE during exposure to erythromycin or metoclopramide was hyperkalemia (8.6/1000 infant days on erythromycin and 11.0/1000 infant days on metoclopramide). Incidence of pyloric stenosis was greater with erythromycin than with metoclopramide (10/1095, 0.9% vs 76/19,001, 0.4%; P = 0.01), but odds were not significantly increased after adjusting for covariates (odds ratio 0.52, 95% confidence interval [CI] 0.26-1.02, P = 0.06). More infants experienced an AE while treated with metoclopramide than with erythromycin (odds ratio 1.21, 95% CI 1.03-1.43).

CONCLUSIONS

Metoclopramide was associated with increased risk of AEs compared with erythromycin. Studies are needed to confirm safety and effectiveness of both the drugs in infants.

Utilization of potentially inappropriate medications in elderly patients in a tertiary care teaching hospital in India

Aim:

To evaluate the use of potentially inappropriate medicines in elderly inpatients in a tertiary care teaching hospital.

Materials and Methods:

Retrospective analysis was performed for cases of elderly patients admitted between January 2010 and December 2010. Data on age, gender, diagnosis, duration of hospital stay, treatment, and outcome were collected. Prescriptions were assessed for the use of potentially inappropriate medications in geriatric patients by using American Geriatric Society Beer's criteria (2012) and PRISCUS list (2010).

Results:

A total of 676 geriatric patients (52.12% females) were admitted in the medicine ward. The average age of geriatric patients was 72.69 years. According to Beer's criteria, at least one inappropriate medicine was prescribed in 590 (87.3%) patients. Metoclopramide (54.3%), alprazolam (9%), diazepam (8%), digoxin > 0.125 mg/day (5%), and diclofenac (3.7%) were the commonly used inappropriate medications. Use of nonsteroidal anti-inflammatory drugs (NSAIDs) in heart and renal failure patients was the commonly identified drug–disease interaction. According to PRISCUS list, at least one inappropriate medication was prescribed in 210 (31.06%) patients.

Conclusion:

Use of inappropriate medicines is highly prevalent in elderly patients.

Should we stop prescribing metoclopramide as a prokinetic drug in critically ill patients?

Regulatory agencies in North America and Europe recently re-evaluated the safety of metoclopramide. This re-evaluation resulted in recommendations and restrictions in order to minimise the risk of neurological and other adverse reactions associated with the use of metoclopramide. In the ICU, off-label prescription of metoclopramide is common. We have reviewed the evidence for safety, effectiveness and dosing of metoclopramide in critically ill patients. Furthermore, tachyphylaxis is addressed and alternatives are summarised. Finally, recommendations are presented not to abandon use of metoclopramide in ICU patients, because metoclopramide is considered effective in enhancing gastric emptying and facilitating early enteral nutrition.

Metoclopramide nasal spray is effective in symptoms of gastroparesis in diabetics compared to conventional oral tablet

BACKGROUND

Delayed gastric emptying symptoms interfere with the absorption of oral medications. Intranasal metoclopramide is being developed as an alternative to oral metoclopramide for patients with diabetic gastroparesis.

METHODS

To compare the efficacy and safety of metoclopramide nasal spray to oral tablets in diabetic patients with symptoms of gastroparesis, this randomized, open-label, parallel design study randomized subjects to 10 or 20 mg nasal spray or 10 mg tablet four times a day for 6 weeks. Efficacy was evaluated using a total symptom score (TSS).

KEY RESULTS

Eighty-nine subjects were enrolled. For the intention to treat population, both nasal dose groups (10 and 20 mg) had lower TSS with treatment compared to the oral 10 mg group. The change from baseline in TSS for nasal 20 mg was greater than the oral 10 mg at Week 6 (p = 0.026). For the per-protocol population, there was a significant difference in the TSS between baseline and Week 6 for both the nasal 10 mg (p = 0.026) and the nasal 20 mg (p = 0.008) cohorts compared to the oral 10 mg group. Based on the definition of a responder, 88.9% of subjects who received oral 10 mg, 91.2% who received nasal 10 mg, and 97.1% who received nasal 20 metoclopramide were classified as responders. The side-effect profile of the metoclopramide nasal spray was favorable. More side effects, especially nausea, occurred with the oral tablets.

CONCLUSIONS & INFERENCES

Metoclopramide nasal spray offers better symptom control than metoclopramide oral tablet in diabetic patients with symptoms of gastroparesis.

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.

Glomerular filtration rate equations overestimate creatinine clearance in older individuals enrolled in the Baltimore Longitudinal Study on Aging: impact on renal drug dosing

OBJECTIVES

To evaluate the performance of kidney function estimation equations and to determine the frequency of drug dose discordance in an older population.

DESIGN

Cross-sectional analysis of data from community-dwelling volunteers randomly selected from the Baltimore Longitudinal Study of Aging from January 1, 2005, to December 31, 2010.

SUBJECTS

A total of 269 men and women with a mean ± SD age of 81 ± 6 years, mean serum creatinine concentration (Scr ) of 1.1 ± 0.4 mg/dl, and mean 24-hour measured creatinine clearance (mClcr ) of 53 ± 13 ml/minute.

MEASUREMENTS AND MAIN RESULTS

Kidney function was estimated by using the following equations: Cockcroft-Gault (CG), Modification of Diet in Renal Disease (MDRD), and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI). The performance of each equation was assessed by measuring bias and precision relative to mClcr . Dose calculation errors (discordance) were determined for 10 drugs requiring renal dosage adjustments to avoid toxicity when compared with the dosages approved by the Food and Drug Administration. The CG equation was the least biased estimate of mClcr . The MDRD and CKD-EPI equations were significantly positively biased compared with CG (mean ± SD 34 ± 20% and 22 ± 15%, respectively, p<0.001) and mClcr (29 ± 47% and 18 ± 40%, respectively, p<0.001). Rounding low Scr values (less than 1.0 mg/dl) up to an arbitrary value of 1.0 mg/dl resulted in CG values (44 ± 10 ml/minute) that were significantly lower than mClcr (56 ± 12 ml/minute, p<0.001) and CG (56 ± 15 ml/minute, p<0.001). The MDRD and CKD-EPI equations had median dose discordance rates of 28.6% and 22.9%, respectively.

CONCLUSION

The MDRD and CKD-EPI equations significantly overestimated creatinine clearance (mClcr and CG) in elderly individuals. This leads to dose calculation errors for many drugs, particularly in individuals with severe renal impairment. Thus equations estimating glomerular filtration rate should not be substituted in place of the CG equation in older adults for the purpose of renal dosage adjustments. In addition, the common practice of rounding or replacing low Scr values with an arbitrary value of 1.0 mg/dl for use in the CG equation should be avoided. Additional studies that evaluate alternative eGFR equations in the older populations that incorporate pharmacokinetic and pharmacodynamic outcomes measures are needed.

Gastroparesis: concepts, controversies, and challenges

Patients with gastroparesis often present a challenge to the treating physician. Postprandial symptoms with nausea and vomiting may not only lead to nutritional and metabolic consequences, but also cause significant disruptions to social activities that often center around food. While the definition of gastroparesis focuses on impaired gastric emptying, treatment options that affect gastric function are limited and often disappointing. The female predominance, the mostly idiopathic nature of the illness with a common history of abuse, and coexisting anxiety or depression show parallels with other functional disorders of the gastrointestinal tract. These parallels provided the rationale for some initial studies investigating alternative therapies that target the brain rather than the stomach. This emerging shift in medical therapy comes at a time when clinical studies suggest that gastric electrical stimulation may exert its effects by modulating visceral sensory processing rather than altering gastric motility. Physiologic and detailed anatomic investigations also support a more complex picture with different disease mechanisms, ranging from impaired accommodation to apparent visceral hypersensitivity or decreased interstitial cells of Cajal to inflammatory infiltration of myenteric ganglia. Delayed gastric emptying remains the endophenotype defining gastroparesis. However, our treatment options go beyond prokinetics and may allow us to improve the quality of life of affected individuals.

Management of diabetic gastroparesis

Symptoms suggestive of gastroparesis occur in 5% to 12% of patients with diabetes. Such a complication can affect both prognosis and management of the diabetes; therefore, practicing clinicians are challenged by the complex management of such cases. Gastroparesis is a disorder characterized by a delay in gastric emptying after a meal in the absence of a mechanical gastric outlet obstruction. This article is an evidence-based overview of current management strategies for diabetic gastroparesis. The cardinal symptoms of diabetic gastroparesis are nausea and vomiting. Gastroesophageal scintiscanning at 15-minute intervals for 4 hours after food intake is considered the gold standard for measuring gastric emptying. Retention of more than 10% of the meal after 4 hours is considered an abnormal result, for which a multidisciplinary management approach is required. Treatment should be tailored according to the severity of gastroparesis, and 25% to 68% of symptoms are controlled by prokinetic agents. Commonly prescribed prokinetics include metoclopramide, domperidone, and erythromycin. In addition, gastric electrical stimulation has been shown to improve symptoms, reduce hospitalizations, reduce the need for nutritional support, and improve quality of life in several open-label studies.

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.

Pharmacotherapy of gastroparesis

Gastroparesis is a relatively common and often disabling condition that is characterized by a broad range of clinical presentation ranging from dyspeptic symptoms to nausea, vomiting, abdominal pain, malnutrition, frequent hospitalizations and incapacitation. The treatment of gastroparetic symptoms can be challenging to the gastroenterologist and the intensity of therapy varies with the physician's knowledge. Hence the determination that a patient is refractory to 'standard medical therapy' is an assessment that is subspeciality-based and could differ around the world depending on medications available. In this article, we review the use of available prokinetics, antiemetic agents, the approach for analgesia in the context of gastroparesis, and also discuss potential and evolving pharmacotherapies. The progress has been relatively limited as far as availability of new medications for gastroparesis is concerned; however, active research in developing newer prokinetics holds great promise for the future of management of this challenging entity.

Failure of recognition of drug-induced parkinsonism in the elderly

Our objective was to evaluate the ability of neurologists to recognize and diagnose drug-induced Parkinsonism (DIP) in the elderly. DIP is a diagnostic challenge because it can be indistinguishable from Parkinson's disease, especially in the elderly. It is frequently under-recognized by psychiatrists and primary care physicians. Atypical antipsychotics (AA) are advertised for their low propensity to cause DIP. This may add to problems with recognition. We performed a retrospective record review of consecutive new parkinsonian patients seen over 2 years in a movement disorders clinic to examine the frequency, causative agents, and diagnostic accuracy of DIP by physicians, particularly neurologists. Of 354 Parkinsonian patients evaluated, 24 (6.8%) had DIP, 46% of these were due to AA and 29% were caused by metoclopramide. Of the 24 patients with DIP, only one was previously diagnosed accurately according to records. Nineteen patients (79%) were previously evaluated by a neurologist, and none of them was diagnosed with DIP. The primary reason for failure to recognize DIP relates to under-recognition of AA as possible cause. A majority remained on the inciting agents while dopaminergic drugs were prescribed. DIP was reversible when the inciting drug was stopped. DIP is a common form of parkinsonism and is under-recognized, even by neurologists. AA and metoclopramide do not appear to be well-known to cause DIP. Cessation of the offending agent results in improvement of symptoms and would eliminate the need for dopaminergic agents, which are known to commonly cause side effects in the elderly.

Treatment of tardive dyskinesia with levetiracetam in a transplant patient

OBJECTIVE

To describe successful treatment of tardive dyskinesia with levetiracetam.

BACKGROUND

Tardive dyskinesia is a late-onset movement disorder caused by exposure to dopamine receptor blocking agents, most commonly neuroleptics. Metoclopramide is frequently used to treat gastrointestinal dysmotility. It has antidopaminergic properties, and is estimated to be responsible for two-thirds of drug-related movement disorders.

DESIGN/METHODS

Case report.

RESULTS

A 68-year-old woman presented with a history of intestinal transplantation (12 years ago; short gut syndrome related to bowel resection for rectal carcinoma) and renal transplantation (1 year ago; diabetes). She developed involuntary movements with stereotypic oro-buccal-lingual dyskinesias and right-sided choreiform movements. Her Abnormal Involuntary Movement Scale score (AIMS) score was 27. She has been treated with metoclopramide for gastrointestinal dysmotility for more than 10 years and was diagnosed with tardive dyskinesia. Treatment with levetiracetam 250 mg orally b.i.d. led to a significant improvement of abnormal movements within a week. Her AIMS score decreased to 8.

DISCUSSION

Tardive dyskinesia may be quite disabling and options include withdrawal of offending medication, or use of tetrabenazine or reserpine. Several reports also suggested improvement of tardive movement disorders with levetiracetam. In our patient, levetiracetam relieved symptoms of tardive dyskinesia and allowed continuous use of metoclopramide. Larger studies are needed to confirm its efficacy.

Review article: The diagnosis and management of gastroparesis

BACKGROUND

Gastroparesis is a disorder characterized by a delay in gastric emptying of a meal in the absence of a mechanical gastric outlet obstruction.

AIM

To provide an evidence based overview on diagnosis and management of gastroparesis.

METHODS

A PubMed search was performed using search terms including gastroparesis, gastric retention, gastric emptying, accommodation, manometry, prokinetics, antiemetics, metoclopramide, domperidone, erythromycin, botulinum toxin, gastric pacing. Relevant studies were identified and original articles and reviews were collected. References in these articles were examined for relevance and included where appropriate.

RESULTS

Diagnosis of gastroparesis is based on the presence of symptoms such as nausea, vomiting and postprandial abdominal fullness and on an objectively determined delay in gastric emptying. The true prevalence of gastroparesis is unknown. Gastric emptying can be assessed by scintigraphy and stable isotope breath tests. Management of gastroparesis consists of dietary and lifestyle measures and/or pharmacological interventions (prokinetics, antiemetics, intrapyloric botulinum toxin injection) or other interventions that focus on adequate nutrient intake either through a nasoduodenal tube, percutaneous gastrostomy or jejunostomy.

CONCLUSIONS

Accurate diagnosis of gastroparesis requires an adequate protocol to measure gastric emptying. Treatment options in gastroparesis remain limited despite the disabling nature of the disorder.

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.

Metoclopramide for the treatment of gastroesophageal reflux disease in infants: a systematic review

OBJECTIVES

Metoclopramide is a commonly used drug to treat gastroesophageal reflux disease in infants. Given its widespread use and growing concern about toxicity in this population, we conducted a systematic review of metoclopramide for the treatment of gastroesophageal reflux disease in infants.

METHODS

We performed a systematic search of PubMed and bibliographies of relevant review articles. We included cohort, case-control, and intervention studies of the efficacy, effectiveness, or toxicity of metoclopramide therapy for gastroesophageal reflux disease in infants. We excluded case reports, case series, review articles, and abstracts.

RESULTS

Twelve articles met our inclusion criteria. Of these, 11 were prospective trials, and 5 were randomized, blinded clinical trials. Study size ranged from 6 to 77 patients. Eight studies showed patient improvement with metoclopramide in at least 1 measured outcome; 1 study showed worsening symptoms with metoclopramide. Of the 5 randomized, blinded trials, 2 showed no effect of metoclopramide on any outcome, and 2 showed a significant placebo effect. Four studies commented on adverse effects of therapy, with irritability being the most frequently reported potential adverse effect of therapy. Other reported adverse effects included dystonic reactions, drowsiness, oculogyric crisis, emesis, and apnea. Among studies, there was marked heterogeneity in the patient populations, dosing, and outcomes studied. Therefore, a meta-analysis was not performed. We both agreed on a US Preventive Service Task Force rating of "poor" for the level of evidence, leading to an "inconclusive" recommendation for the safety and efficacy of metoclopramide in infants.

CONCLUSIONS

The current literature is insufficient to either support or oppose the use of metoclopramide for gastroesophageal reflux disease in infants. In the future, large blinded randomized clinical trials are needed to determine the efficacy and toxicity of metoclopramide in this population.

Treatment of gastroparesis: a multidisciplinary clinical review

This clinical review on the treatment of patients with gastroparesis is a consensus document developed by the American Motility Society Task Force on Gastroparesis. It is a multidisciplinary effort with input from gastroenterologists and other specialists who are involved in the care of patients with gastroparesis. To provide practical guidelines for treatment, this document covers results of published research studies in the literature and areas developed by consensus agreement where clinical research trials remain lacking in the field of gastroparesis.

Current Choices—Good or Bad—for the Proactive Management of Postoperative Ileus: A Surgeon’s View

Postoperative ileus (POI) is frequently experienced by many patients undergoing abdominal operations and other surgical procedures. Postoperative ileus causes physical discomfort and may increase risk for prolonged hospital length of stay. Despite its prevalence, there is currently no accepted standard definition of POI and, consequently, no standardized mode of prevention or treatment; it is no wonder that a variety of management approaches for POI have been developed. Some of these include alternative surgical techniques such as laparoscopic or endoscopic procedures to minimize trauma and help lessen the release of endogenous mediators of POI. Others have evaluated alternate analgesic regimens such as thoracic epidural anesthetics to avoid stimulating opioid receptors in the gut. These approaches have had varying results. Other pharmacologic attempts to reduce POI have focused on the blockade of opioid receptors to prevent opioid-induced GI-related adverse effects. A new class of agents, peripherally acting mu-opioid-receptor antagonists such as methylnaltrexone and alvimopan, may improve the pharmacologic management of POI and reshape the current paradigm of multimodal management of POI. Protocols that incorporate these agents may offer yet another avenue to mitigate the adverse effects of POI, and thus help improve surgical outcomes. To date, alvimopan has been shown in phase 3 clinical trials to significantly reduce the duration of POI while maintaining satisfactory analgesia and reducing length of hospital stay. Combinations of strategies with demonstrated effectiveness such as early feeding, epidural analgesia, laparoscopic surgery, and peripherally acting mu-opioid-receptor antagonists may help transform the management of POI into an effective multimodal paradigm that targets the diverse etiologic factors leading to this common clinical problem. Clearly, all surgical team members are crucial in the optimal implementation of such multimodal approaches.

Drug Insight: from disturbed motility to disordered movement—a review of the clinical benefits and medicolegal risks of metoclopramide

Metoclopramide, the only drug approved by the FDA for treatment of diabetic gastroparesis, but used off-label for a variety of other gastrointestinal indications, has many potentially troublesome adverse neurologic effects, particularly movement disorders. In this article, we comprehensively review the indications and side effects of metoclopramide, and describe some common pitfalls and strategies to minimize the medicolegal risks to the prescribing physician. Metoclopramide accounts for nearly a third of all drug-induced movement disorders, a common reason for a malpractice suit. The entire spectrum of drug-induced movement disorders, ranging from subtle to life-threatening, can ensue from its use; akathisia and dystonia are generally seen early in the course of metoclopramide-induced movement disorders, whereas tardive dyskinesia and parkinsonism seem to be more prevalent in chronic users. Female sex, age and diabetes are the major risk factors for metoclopramide-induced movement disorders. It is therefore incumbent on gastroenterologists and other prescribing physicians to become familiar with the adverse neurologic effects associated with the use of metoclopramide, and to take appropriate preventive and defensive measures.

New management approaches for gastroparesis

Management of patients with gastroparesis is challenging. Although the syndrome has multiple causes and knowledge of the pathophysiology and natural history is far from complete, a number of common management principles can be applied. The relatively poor correlation between upper-gastrointestinal symptoms and disordered gastric emptying represents a major difficulty in the therapeutic approach, and evidence to support the efficacy of current management strategies is often suboptimal, especially in relation to long-term therapy. In this review, the common causes and pathophysiology of gastroparesis are summarized, the diagnostic approach considered, and the evidence to support medical and surgical therapies reviewed. These therapies include currently available prokinetic drugs, novel medical therapies, and the promising technique of gastric electrical stimulation.