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

Drug-induced parkinsonism: diagnosis and treatment

INTRODUCTION

Drug-induced parkinsonism (DIP) is one of the most common iatrogenic movement disorders. It is characterized by tremors, slowness of movement, and shuffling gait with postural instability, clinically indistinguishable from idiopathic Parkinson's disease. Prior exposure to antipsychotic medications or other dopamine receptor blocking agents (DRBAs) is required for the diagnosis.

AREAS COVERED

This article aims to review the epidemiology, pathophysiology, clinical features, ancillary testing, and treatment of DIP. A literature search was undertaken in PubMed from January 2013 to January 2024.

EXPERT OPINION

A clinician's suspicion of DIP must always be present when a patient develops acute to subacute onset of parkinsonism while taking a DRBA. As DIP can be indistinguishable from idiopathic PD, ancillary testing, such as DaTscans and skin biopsy searching for alpha-synuclein deposits, are often required to make a definitive diagnosis. When DIP develops, steps should be taken to discontinue the offending agent or, in the case of antipsychotics, dose reduction or change to an agent with lower risk for DIP, such as quetiapine or clozapine. Prophylactic treatment with anticholinergics is not indicated.

Cu-Electrocatalysis Enables Vicinal Bis(difluoromethylation) of Alkenes: Unraveling Dichotomous Role of Zn(CF2H)2(DMPU)2 as Both Radical and Anion Source

The difluoromethyl group (CF2H) serves as an essential bioisostere in drug discovery campaigns according to Lipinski's Rule of 5 due to its advantageous combination of lipophilicity and hydrogen bonding ability, thereby improving the ADME properties. However, despite the high prevalence and importance of vicinal hydrogen bond donors in pharmaceutical agents, a general synthetic method for doubly difluoromethylated compounds in the vicinal position is absent. Here we describe a copper-electrocatalyzed strategy that enables the vicinal bis(difluoromethylation) of alkenes. By leveraging electrochemistry to oxidize Zn(CF2H)2(DMPU)2-a conventionally utilized anionic transmetalating source, we paved a way to utilize it as a CF2H radical source to deliver the CF2H group in the terminal position of alkenes. Mechanistic studies revealed that the interception of the resultant secondary radical by a copper catalyst and subsequent reductive elimination is facilitated by invoking the Cu(III) intermediate, enabling the second installation of the CF2H group in the internal position. The utility of this electrocatalytic 1,2-bis(difluoromethylation) strategy has been highlighted through the late-stage bioisosteric replacement of pharmaceutical agents such as sotalol and dipivefrine.

Seven-Year Experience of Intramural Surgery in the Middle East: A Safety and Feasibility Analysis

Background: Intramural surgery techniques, particularly esophageal peroral endoscopic myotomy (E-POEM), gastric peroral endoscopic myotomy (G-POEM), and peroral endoscopic myotomy for Zenker's (Z-POEM), have emerged as forefront minimally invasive endoscopic procedures. While several studies have reported on the outcomes in North America and Asia, evidence in the Middle East and North Africa remains limited. This study aims to evaluate the feasibility and safety of intramural surgery techniques within this region. Methods: This retrospective cohort study was conducted with approval from the institutional review board. All patients who underwent esophageal peroral endoscopic myotomy, gastric peroral endoscopic myotomy, and peroral endoscopic myotomy for Zenker's from January 2016 to August 2023 were included. Results: In total, 119 patients underwent intramural surgery procedures during this period. The esophageal peroral endoscopic myotomy group had 81 (68%) patients, the gastric peroral endoscopic myotomy had 34 (28.6%) patients, and the peroral endoscopic myotomy for Zenker's had 4 (3.4%) patients. The full cohort was 48.7% female, with a mean overall age of 40.5 years. The mean overall body mass index was 27.5 kg/m2. The chief complaint was dysphagia (n = 80, 67.2%). All cases were successfully completed endoscopically. During the first 30 days, the most common complications were nausea/vomiting requiring admission (n = 4, 4.76%) and pneumomediastinum (n = 2, 2.38%). At a follow-up of 19 months, there were four mortalities; the causes of death were cardiac arrest (three cases) and end-stage prostate cancer (one case). Conclusions: Intramural surgery techniques are safe and technically feasible with low complication rates. Our study suggests that clinical success in the Middle East and Northern Africa population is comparable to larger international series.

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.

PEGylated Tween 80-functionalized chitosan-lipidic nano-vesicular hybrids for heightening nose-to-brain delivery and bioavailability of metoclopramide

A PEGylated Tween 80-functionalized chitosan-lipidic (PEG-T-Chito-Lip) nano-vesicular hybrid was developed for intranasal administration as an alternative delivery route to help improve the poor oral bioavailability of BCS class-III model/antiemetic (metoclopramide hydrochloride; MTC). The influence of varying levels of chitosan, cholesterol, PEG 600, and Tween 80 on the stability/release parameters of the formulated nanovesicles was optimized using Draper-Lin Design. Two optimized formulations (Opti-Max and Opti-Min) with both maximized and minimized MTC-release goals, were predicted, characterized, and proved their vesicular outline via light/electron microscopy, along with the mutual prompt/extended in-vitro release patterns. The dual-optimized MTC-loaded PEG-T-Chito-Lip nanovesicles were loaded in intranasal in-situ gel (ISG) and further underwent in-vivo pharmacokinetics/nose-to-brain delivery valuation on Sprague-Dawley rats. The absorption profiles in plasma (plasma-AUC_0-∞) of the intranasal dual-optimized MTC-loaded nano-vesicular ISG formulation in pretreated rats were 2.95-fold and 1.64-fold more than rats pretreated with orally administered MTC and intranasally administered raw MTC-loaded ISG formulation, respectively. Interestingly, the brain-AUC_0-∞ of the intranasal dual-optimized MTC-loaded ISG was 10 and 3 times more than brain-AUC_0-∞ of the MTC-oral tablet and the intranasal raw MTC-loaded ISG, respectively. It was also revealed that the intranasal dual-optimized ISG significantly had the lowest liver-AUC_0-∞ (862.19 ng.g^-1.h^-1) versus the MTC-oral tablet (5732.17 ng.g^-1.h^-1) and the intranasal raw MTC-loaded ISG (1799.69 ng.g^-1.h^-1). The brain/blood ratio profile for the intranasal dual-optimized ISG was significantly enhanced over all other MTC formulations (P < 0.05). Moreover, the 198.55% drug targeting efficiency, 75.26% nose-to-brain direct transport percentage, and 4.06 drug targeting index of the dual-optimized formulation were significantly higher than those of the raw MTC-loaded ISG formulation. The performance of the dual-optimized PEG-T-Chito-Lip nano-vesicular hybrids for intranasal administration evidenced MTC-improved bioavailability, circumvented hepatic metabolism, and enhanced brain targetability, with increased potentiality in heightening the convenience and compliance for patients.

Drug-Induced Movement Disorders

Drug-induced movement disorders (DIMDs) are most commonly associated with typical and atypical antipsychotics. However, other drugs such as antidepressants, antihistamines, antiepileptics, antiarrhythmics, and gastrointestinal drugs can also cause abnormal involuntary movements. Different types of movement disorders can also occur because of adverse drug reactions. Therefore, the important key to diagnosing DIMDs is a causal relationship between potential offending drugs and the occurrence of abnormal movements. The pathophysiology of DIMDs is not clearly understood; however, many cases of DIMDs are thought to exert adverse mechanisms of action in the basal ganglia. The treatment of some DIMDs is quite challenging, and removing the offending drugs may not be possible in some conditions such as withdrawing antipsychotics in the patient with partially or uncontrollable neuropsychiatric conditions. Future research is needed to understand the mechanism of DIMDs and the development of drugs with better side-effect profiles. This article reviews the phenomenology, diagnostic criteria, pathophysiology, and management of DIMDs.

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.

Usefulness of Optimized Human Fecal Material in Simulating the Bacterial Degradation of Sulindac and Sulfinpyrazone in the Lower Intestine

The first aim of this study was to evaluate the usefulness of optimized human fecal material in simulating sulforeductase activity in the lower intestine by assessing bacterial degradation of sulindac and sulfinpyrazone, two sulforeductase substrates. The second aim was to evaluate the usefulness of drug degradation half-life generated in simulated colonic bacteria (SCoB) in informing PBPK models. Degradation experiments of sulfinpyrazone and of sulindac in SCoB were performed under anaerobic conditions using recently described methods. For sulfinpyrazone, the abundance of clinical data allowed for construction of a physiologically based pharmacokinetic (PBPK) model and evaluation of luminal degradation clearance determined from SCoB data. For sulindac, the availability of sulindac sulfide and sulindac sulfone standards allowed for evaluating the formation of the main metabolite, sulindac sulfide, during the experiments in SCoB. Both model compounds degraded substantially in SCoB. The PBPK model was able to adequately capture exposure of sulfinpyrazone and its sulfide metabolite in healthy subjects, in ileostomy and/or colectomy subjects, and in healthy subjects pretreated with metoclopramide by implementing degradation half-lives in SCoB to calculate intrinsic colon clearance. Degradation rates of sulindac and formation rates of sulindac sulfide in SCoB were almost identical, in line with in vivo data suggesting the sulindac sulfide is the primary metabolite in the lower intestine. Experiments in SCoB were useful in simulating sulforeductase related bacterial degradation activity in the lower intestine. Degradation half-life calculated from experiments in SCoB is proven useful for informing a predictive PBPK model for sulfinpyrazone.

Emerging Progress in Nausea and Vomiting of Pregnancy and Hyperemesis Gravidarum: Challenges and Opportunities

Nausea and vomiting of pregnancy (NVP) is a common condition that affects up to 70% of pregnant women. Hyperemesis gravidarum (HG) is considered the serious form of NVP, which is reported in 0.3–10.8% of pregnant women. NVP has a relatively benign course, but HG can be linked with some poor maternal, fetal, and offspring outcomes. The exact causes of NVP and HG are unknown, but various factors have been hypothesized to be associated with pathogenesis. With the advance of precision medicine and molecular biology, some genetic factors such as growth/differentiation factor 15 (GDF15) have become therapeutic targets. In our review, we summarize the historical hypotheses of the pathogenesis of NVP and HG including hormonal factors, Helicobacter pylori, gastrointestinal dysmotility, placenta-related factors, psychosocial factors, and new factors identified by genetics. We also highlight some approaches to the management of NVP and HG, including pharmacological treatment, complementary treatment, and some supporting treatments. Looking to the future, progress in understanding NVP and HG may reduce the adverse outcomes and improve the maternal quality of life during pregnancy.

Functional syndromes and symptom-orientated aftercare after esophagectomy

BACKGROUND

Surgery is the cornerstone of esophageal cancer treatment but remains burdened with significant postoperative changes of gastrointestinal function and quality of life.

PURPOSE

The aim of this narrative review is to assess and summarize the current knowledge on postoperative functional syndromes and quality of life after esophagectomy for cancer, and to provide orientation for the reader in the challenging field of functional aftercare.

CONCLUSIONS

Post-esophagectomy syndromes include various conditions such as dysphagia, reflux, delayed gastric emptying, dumping syndrome, weight loss, and chronic diarrhea. Clinical pictures and individual expressions are highly variable and may be extremely distressing for those affected. Therefore, in addition to a mostly well-coordinated oncological follow-up, we strongly emphasize the need for regular monitoring of physical well-being and gastrointestinal function. The prerequisite for an effective functional aftercare covering the whole spectrum of postoperative syndromes is a comprehensive knowledge of the pathophysiological background. As functional conditions often require a complex diagnostic workup and long-term therapy, close interdisciplinary cooperation with radiologists, gastroenterologists, oncologists, and specialized nutritional counseling is imperative for successful management.

Metoclopramide-induced acute dystonic reactions: a case report

Background

Acute dystonic reactions caused by drugs are uncommon in daily practice, whether in outpatient or in emergency settings. Such types of unfavorable reaction may cause the treating physician’s working diagnosis to be misled at a certain point.

Case presentation

A 25-year-old Hindu female from Dharan with no previous medical history was being treated for acid peptic disease. Her local physician prescribed oral tablet metoclopramide 10 mg three times a day for 7 days and tablet pantoprazole 40 mg once daily for 7 days. After 24 hours of ingestion of 10 mg of tablet metoclopramide, she was admitted to our Koirala Institute of Health Sciences emergency department with sudden history of facial twitching, slurred speech, and abnormal tongue protrusion. Metoclopramide-induced acute dystonic reaction was diagnosed. After resuscitation, her symptoms reduced quickly, and she was successfully discharged home the same day.

Conclusions

Early diagnosis would be aided by the use of clinical background along with focus on drug history usage, preventing life-threatening pitfalls. To decrease the acute dystonic reaction associated with metoclopramide use, higher frequency of prescription patterns should be taken into account.

Mental health mediators of subjective cognitive concerns among World Trade Center responders

Decline in cognitive functioning among rescue and recovery workers who responded in the aftermath of the September 11, 2001, World Trade Center (WTC) attacks is of emerging interest. Responders are vulnerable to cognitive decline from exposure to airborne toxins present at the WTC site, as well as from WTC-related mental and physical health conditions. To better understand the relationship between occupational WTC exposure, mental health, physical health and subjective cognitive functioning, we examined the mediating role of health status in the association between exposure and subjective cognitive concerns in a multi-site, longitudinal investigation of the WTC General Responder cohort (n = 16,380 responders; n = 58,575 visits) for the period 2002-2015. Through latent class analyses, we identified a four-level marker of cognitive concerns based on information from a Self-Administered Mental Health Questionnaire. Using generalized linear mixed models with random intercepts, we observed that a higher intensity WTC exposure composite was associated with greater cognitive concerns, and that this association was operating almost entirely through mental health comorbidities, not physical health comorbidities. In fully adjusted models, the inclusion of probable depression, anxiety, PTSD and use of psychotropic medications attenuated the association between highest WTC exposure and greatest cognitive concerns. Physical health did not appear to be on the pathway between WTC exposure and cognitive concerns. Understanding the underlying sources of cognitive concerns may help identify vulnerable members of the General Responder cohort and potentially aid clinical decision-making, such as treatment choice and enhanced screening options. Earlier diagnosis and symptom treatment may help preserve functional independence.

Supportive medication in cancer during pregnancy

While pregnancy-related malignancies are quite rare, their incidence is increasing and thus affecting more and more women nowadays. Their management, however, with both chemotherapy and supportive agents remains quite challenging and it seems crucial to define the optimal treatment for this special population. Concerning supportive medication, it is clinically significant to determine whether commonly used agents, including Granulocyte Colony-Stimulating Factors, Erythropoiesis-stimulating agents, Bisphosphonates, Anticoagulation agents, Antiemetics and Glucocorticoids are indeed effective in ameliorating chemotherapy side effects. Meanwhile, it is of great importance that the administration of any of these agents is safe for both mother and fetus. This review aims to provide a précis of the current literature regarding both safety and efficacy of all categories of supportive medication during pregnancy.

Prophylactic Administration of Diphenhydramine to Reduce Neuroleptic Side Effects in the Acute Care Setting: A Systematic Review and Meta-Analysis

BACKGROUND

Neuroleptics are commonly prescribed drugs to treat acute conditions (e.g., migraines) in the emergency department, but can cause serious adverse effects. Using diphenhydramine to prevent these adverse effects is very common but remains controversial.

OBJECTIVE

We performed a systematic review to determine whether prophylactic administration of diphenhydramine reduces the incidence of neuroleptic adverse effects in patients with acute conditions.

METHODS

Medline, Embase, Cochrane, PsycInfo, and Web of Science were searched for randomized controlled trials evaluating any neuroleptic with diphenhydramine vs. the same neuroleptic with any inactive agent. Primary outcome was incidence of any extrapyramidal adverse effect. Secondary outcomes were akathisia, rescue medication, subjective restlessness, neuroleptic malignant syndrome, and sedation. Independent reviewers scanned identified citations, extracted data, and assessed risk of bias. Meta-analysis was performed using random effect models.

RESULTS

Of 1566 identified citations, nine studies (n = 1648 patients) met eligibility criteria. Four studies were specifically designed to compare the incidence of neuroleptic adverse effects with and without co-administration of diphenhydramine. Four studies were at high risk of bias. In primary analysis, diphenhydramine had no effect on the incidence of extrapyramidal symptoms (7 studies, n = 1393, risk ratio [RR] 0.75; 95% confidence interval [CI] 0.44-1.31) or akathisia (5 studies, n = 1094; RR 0.78; 95% CI 0.33-1.82) or any of the secondary outcomes. In subgroup analysis, diphenhydramine was associated with a significant decrease in extrapyramidal adverse effects compared with placebo (4 studies, n = 705; RR 0.61; 95% CI 0.41-0.90). Dosage analysis yielded no further information.

CONCLUSIONS

When compared with placebo, diphenhydramine was associated with a significant reduction of extrapyramidal adverse effects. Overall quality of evidence is low. Further studies are warranted.

Impaired Clearance From the Brain Increases the Brain Exposure to Metoclopramide in Elderly Subjects

The antiemetic and gastroprokinetic drug metoclopramide is a weak substrate of the blood‐brain barrier (BBB) efflux transporter P‐gp and displays central nervous system (CNS) side effects (i.e., extrapyramidal symptoms and tardive dyskinesia) caused by dopamine D₂ receptor blockade in the basal ganglia. These side effects occur with a higher incidence in elderly people. We used positron emission tomography to assess the brain distribution of [¹¹C]metoclopramide in young (n = 11, 26 ± 3 years) and elderly (n = 7, 68 ± 9 years) healthy men both after administration of a microdose (9 ± 7 µg) and a microdose co‐injected with a therapeutic dose of unlabeled metoclopramide (10 mg). For both doses, elderly subjects had a significantly higher total volume of distribution (V_T) of [¹¹C]metoclopramide in the basal ganglia than young subjects (microdose: +26%, therapeutic dose: +41%). Increases in V_T (= K₁/k₂) were caused by significant decreases in the transfer rate constant of [¹¹C]metoclopramide from brain into plasma (k₂, microdose: −18%, therapeutic dose: −30%), whereas the distributional clearance from plasma into brain (K₁) remained unaltered. This reduction in the clearance of [¹¹C]metoclopramide (k₂) from the brains of elderly subjects may be caused by an age‐related decrease in the activity of P‐gp at the BBB and may contribute to the higher incidence of CNS side effects of metoclopramide in the aged population. Our data suggest that an age‐associated decrease in the clearance properties of the BBB may modulate the CNS effects or side effects of clinically used P‐gp substrates.

Pharmacologic treatment of GERD: Where we are now, and where are we going?

The introduction of acid inhibition in clinical practice has revolutionized the management of acid-related diseases, leading to the virtual abolition of elective surgery for ulcer disease and relegating antireflux surgery to patients with gastroesophageal reflux disease (GERD) not adequately managed by medical therapy. Proton pump inhibitors (PPIs) are the antisecretory drugs of choice for the treatment of reflux disease. However, these drugs still leave some unmet clinical needs in GERD. PPI-refractoriness is common, and persistent symptoms are observed in up to 40-55% of daily PPI users. Potassium-competitive acid blockers (P-CABs) clearly overcome many of the drawbacks and limitations of PPIs, achieving rapid, potent, and prolonged acid suppression, offering the opportunity to address many of the unmet needs. In recent years, it has been increasingly recognized that impaired mucosal integrity is involved in the pathogenesis of GERD. As a consequence, esophageal mucosal protection has emerged as a new, promising therapeutic avenue. When P-CABS are used as add-on medications to standard treatment, a growing body of evidence suggests a significant additional benefit, especially in the relief of symptoms not responding to PPI therapy. On the contrary, reflux inhibitors are considered a promise unfulfilled, and prokinetic agents should only be used on a case-by-case basis.

Gastrointestinal pharmacology: practical tips for the esophagologist

Gastroesophageal reflux disease (GERD) is primarily a motor disorder, and its pathogenesis is multifactorial. As a consequence, treatment should be able to address the underlying pathophysiology. Proton pump inhibitors (PPIs) are the mainstay of medical therapy for GERD, but these drugs only provide the control of symptoms and lesions without curing the disease. However, continuous acid suppression with PPIs is recommended for patients with Barrett's esophagus because of their potential chemopreventive effects. In addition to the antisecretory activity, these compounds display several pharmacological properties, often overlooked in clinical practice. PPIs can indeed affect gastric motility, exert a mucosal protective effect, and an antioxidant, anti-inflammatory, and antineoplastic activity, also protecting cancer cells from developing chemo- or radiotherapeutic resistance. Even in the third millennium, current pharmacologic approaches to address GERD are limited. Reflux inhibitors represent a promise unfulfilled, effective and safe prokinetics are lacking, and antidepressants, despite being effective in selected patients, give rise to adverse events in a large proportion of them. While waiting for new drug classes (like potassium-competitive acid blockers), reassessing old drugs (namely alginate-containing formulations), and paving the new avenue of esophageal mucosal protection are, at the present time, the only reliable alternatives to acid suppression.

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.

Varied Clinical Presentations of Acute Dystonic Reaction Due to Metoclopramide

OBJECTIVES

In this article, in light of the literature, we aimed at discussing data obtained from patients in which extrapyramidal adverse effects that are misdiagnosed as varied clinical presentations developed due to metoclopramide, which is frequently prescribed in pediatric emergency services and in family practice centers for its powerful and rapid antiemetic action.

METHODS

The files of patients who presented to a pediatric clinic at the research hospital of Mustafa Kemal University between January 2017 and January 2018 and who were diagnosed as having acute dystonic reaction were reviewed retrospectively.

RESULTS

Generalized hypertonicity in 4 patients, abnormal involuntary movements in 2 patients, oculogyric crisis in 2 patients, local hypertonia in the wrist and fingers in 2 patients, spasmodic cervical hypertonicity in 2 patients, and trismus in 1 patient were found. Of the patients, 2 were directed to our clinic with early diagnosis of hypocalcemia, 2 with conversion, 3 with meningitis, 1 with epileptic seizure, 1 with status, 1 with mandibular luxation, 1 with tetanus, and 2 with intracranial pathology.

CONCLUSIONS

The extrapyramidal adverse effects of metoclopramide, which is frequently prescribed in pediatric emergency services and in family practice centers, are highly terrifying for children and parents. Furthermore, it may cause severe anxiety especially in pediatric emergency services because it may mimic many serious diseases.

Acute dystonic reaction induced by a single dose of clebopride: A case report

RATIONALE

Clebopride is known as a dopamine antagonist used for alleviating emetic symptoms with minimal side effects. Herein, we report a case of acute dystonic reaction possibly caused by administration of clebopride in a young male.

PATIENT CONCERNS

A 19-year-old with no special medical conditions, visited a local clinic complaining of abdominal discomfort, associated with nausea and vomiting. The patient was prescribed with tiropramide, clebopride, simethicone, and mosapride citrate, only to visit the emergency department for abrupt neck pain followed with dystonic reactions upon oral administration of the drugs. The patient suffered involuntary movements of the neck to the right, while maintaining voluntary motor controls of the neck to the left.

DIAGNOSIS

Vital signs and neurological exams showed no obscurity and the preliminary blood workup (a complete blood count and measurement of electrolytes, inflammatory marker levels, copper concentration, etc) were all within normal ranges. Additional imagery tests including brain computed tomography (CT), neck contrast-enhanced CT, and magnetic resonance imaging failed to prove any focal lesion pertinent to the condition. Drug screening was done and then clebopride was suspected to be the cause of the dystonic reactions.

INTERVENTIONS

Benztropine (1 mg) was administered orally.

OUTCOMES

The patient's symptoms improved after 1 hour, and he was observed for 6 more hours for possible recurrences before he was discharged. The patient was referred to an outpatient neurology department for 1 month, during which he had no recurrence or other extrapyramidal symptoms.

LESSONS

Although it is uncommon to experience extrapyramidal symptoms by clebopride, its chemical closeness to metoclopramide may induce such symptoms under certain clinical situations. Therefore, physicians should take in consideration of this effect and dwell in caution upon prescribing the drug.

Development and psychometric evaluation of the Diabetic Gastroparesis Symptom Severity Diary

Background

Diabetic gastroparesis (DG) is defined as delayed gastric emptying with associated gastrointestinal symptoms, without mechanical obstruction. Patient-reported symptoms are critical for diagnosis and evaluation of treatment benefit in DG. The Diabetic Gastroparesis Symptom Severity Diary (DGSSD), a new patient-reported outcome measure, was developed for use in clinical trials to support product approval and labeling claims for DG treatments.

Materials and methods

Initial DGSSD development was based on a review of the existing instruments and qualitative research (focus groups and cognitive debriefing interviews) in 41 patients with DG. Psychometric evaluations (individual items and composite scores) were conducted using data from Phase IIa and IIb relamorelin clinical trials.

Results

Qualitative research in patients with DG resulted in a six-item DGSSD, included in the Phase IIa trial, addressing symptom severity for nausea, vomiting, abdominal pain, early satiety, and bloating, as well as vomiting frequency. An item addressing severity of postprandial fullness (PPF) was subsequently added based on regulatory advice and included in the Phase IIb trial. Measurement properties were generally strong for weekly averages of daily item and composite scores. Item-level intraclass correlation coefficients ranged from 0.79 to 0.97 and correlations with other measures matched hypothesized patterns; the discriminating ability and responsiveness of the DGSSD were also supported. Multiple methods supported the computation of a composite score based on items addressing nausea, abdominal pain, bloating, and PPF severity.

Conclusion

Qualitative and quantitative evidence support use of the DGSSD as a reliable and valid measure from which to derive endpoints to evaluate treatment benefit in future DG interventional 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.

Impact of P-Glycoprotein Function on the Brain Kinetics of the Weak Substrate 11C-Metoclopramide Assessed with PET Imaging in Humans

PET with avid substrates of P-glycoprotein (ABCB1) provided evidence of the role of this efflux transporter in effectively restricting the brain penetration of its substrates across the human blood-brain barrier (BBB). This may not reflect the situation for weak ABCB1 substrates including several antidepressants, antiepileptic drugs, and neuroleptics, which exert central nervous system effects despite being transported by ABCB1. We performed PET with the weak ABCB1 substrate ¹¹C-metoclopramide in humans to elucidate the impact of ABCB1 function on its brain kinetics. Methods: Ten healthy male subjects underwent 2 consecutive ¹¹C-metoclopramide PET scans without and with ABCB1 inhibition using cyclosporine A (CsA). Pharmacokinetic modeling was performed to estimate the total volume of distribution (V _T) and the influx (K ₁) and efflux (k ₂) rate constants between plasma and selected brain regions. Furthermore, ¹¹C-metoclopramide washout from the brain was estimated by determining the elimination slope (k _E,brain) of the brain time-activity curves. Results: In baseline scans, ¹¹C-metoclopramide showed appreciable brain distribution (V _T = 2.11 ± 0.33 mL/cm³). During CsA infusion, whole-brain gray matter V _T and K ₁ were increased by 29% ± 17% and 9% ± 12%, respectively. K ₂ was decreased by 15% ± 5%, consistent with a decrease in k _E,brain (-32% ± 18%). The impact of CsA on outcome parameters was significant and similar across brain regions except for the pituitary gland, which is not protected by the BBB. Conclusion: Our results show for the first time that ABCB1 does not solely account for the "barrier" property of the BBB but also acts as a detoxifying system to limit the overall brain exposure to its substrates at the human blood-brain interface.

Key Elements in Adverse Drug Reactions Safety Signals: Application of Legal Strategies

Adverse drug reactions, or unintended and harmful outcomes related to the administration of a pharmaceutical product, are a major public health concern, particularly for cancer patients. If counted as a separate cause of death, adverse drug reactions would represent the fourth leading cause of death in the United States. Several legal strategies are available to help mitigate their occurrences and to compensate victims for the harm that results from adverse events. Prior to FDA approval of a drug, the limited size and duration of clinical trials often fail to detect adverse drug reactions. However, after FDA approval, pharmacovigilance efforts are bolstered by recent expansions of FDA post-marketing regulatory powers codified in the 2007 Food and Drug Administration Amendments Act, as well as advances in big data analytics that improve adverse signal detection through data mining of large electronic health records. For victims of adverse drug reactions, tort lawsuits filed in the courts help compensate for the harm suffered and may also serve as warnings to manufacturers to improve drug safety to avoid future legal liability. While encouraging developments have occurred, new and existing legal structures to mitigate and compensate for adverse drug reactions must continue to be refined given increasingly complex pharmaceutical agents.

The Investigation and Treatment of Diabetic Gastroparesis

PURPOSE

This review provides an update on the investigations and treatment options for gastroparesis.

METHODS

A comprehensive literature search of Medline, PubMed, Embase and OVID was conducted which included all systematic reviews and research articles that focused on the diagnosis, investigations and management diabetic gastroparesis.

FINDINGS

Dietary modifications and pharmacologic treatment with prokinetics to increase gastric motility form the mainstay of treatment. However, the use of prokinetics is limited by adverse effects and serious adverse effects, leaving metoclopramide as the only drug approved by the US Food and Drug Administration for the treatment of gastroparesis. Newer therapies, including motilin receptor agonists, ghrelin receptor agonists, and neurokinin receptor antagonists, are currently being investigated. Transpyloric stenting, gastric electrical stimulation, and gastric per-oral endoscopic myotomy provide mechanical options for intervention, and surgical interventions in severe intractable gastroparesis include laparoscopic pyloroplasty or gastrectomy.

IMPLICATIONS

Advances to better understand the pathophysiology and management of diabetic gastroparesis have been limited, especially with discordance between symptoms and severity of delay in gastric emptying. Established treatment options are limited; however, recent pharmacologic and surgical interventions show promise.

Chronic nausea and vomiting: evaluation and treatment

Nausea is an uneasy feeling in the stomach while vomiting refers to the forceful expulsion of gastric contents. Chronic nausea and vomiting represent a diverse array of disorders defined by 4 weeks or more of symptoms. Chronic nausea and vomiting result from a variety of pathophysiological processes, involving gastrointestinal and non-gastrointestinal causes. The prevalence of chronic nausea and vomiting is unclear, although the epidemiology of specific conditions, such as gastroparesis and cyclic vomiting syndrome, is better understood. The economic impact of chronic nausea and vomiting and effects on quality of life are substantial. The initial diagnostic evaluation involves distinguishing gastrointestinal causes of chronic nausea and vomiting (e.g., gastroparesis, cyclic vomiting syndrome) from non-gastrointestinal causes (e.g., medications, vestibular, and neurologic disorders). After excluding anatomic, mechanical and biochemical causes of chronic nausea and vomiting, gastrointestinal causes can be grouped into two broad categories based on the finding of delayed, or normal, gastric emptying. Non-gastrointestinal disorders can also cause chronic nausea and vomiting. As a validated treatment algorithm for chronic nausea and vomiting does not exist, treatment should be based on a thoughtful discussion of benefits, side effects, and costs. The objective of this monograph is to review the evaluation and treatment of patients with chronic nausea and vomiting, emphasizing common gastrointestinal causes.

Gastroparesis: pharmacotherapy and cardiac risk

BACKGROUND

Gastroparesis is characterized by abnormal gastric motility and delayed emptying with symptoms of early satiety, postprandial fullness, bloating, nausea, vomiting and abdominal pain. Pharmacological discovery has been lagging because potential drugs often are associated with abnormalities of electrical conduction of the myocardium due to interaction with cardiac ion channels leading to limited pharmaceutical options for development of new drugs.

OBJECTIVE

Addresses the safety of drugs for gastroparesis in terms of cardiotoxicity related to the clinical use of prokinetics and antiemetics.

METHODS

Survey of QT drugs List and review of current literature.

RESULTS

Many prokinetic drugs are associated with cardiac adverse events and manifest as prolongation of ventricular repolarization, i.e., QT-interval prolongation of the electrocardiogram. This disturbance may develop into a potentially fatal polymorphic ventricular tachyarrhythmia; Torsade de Pointes. Co-administration of prokinetics with other drugs affecting the repolarization process, pharmacokinetic interactions leading to increased blood levels, or the presence of clinical risk factors could further increase the risk for cardiac arrhythmias.

CONCLUSIONS

It is important that clinicians managing gastroparesis are aware of the arrhythmogenic potential of drugs used clinically and risk factors that contribute to QT prolongation to safeguard patients at risk for drug-induced cardiac arrhythmia.

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.

In Search of the Ideal Promotility Agent: Optimal Use of Currently Available Promotility Agents for Nutrition Therapy of the Critically Ill Patient

PURPOSE OF REVIEW

Enteral nutrition therapy is essential in the management of critically ill patients. Prokinetic agents have been used successfully to aid in the delivery of nutrition and improve feeding tolerance in patients in the intensive care unit (ICU). The aim of this report is to review the existing promotility agents available for use in the critically ill as well as outline the role of potential investigative drugs in order to provide a guide to the management of this difficult and important clinical dilemma.

RECENT FINDINGS

While no single currently available agent currently meets all of the desired goals in the critical care setting, there are an increasing number of available agents from which to choose including motilin receptor agonists, 5HT4 receptor agonists, D2 receptor antagonists, and Mu opioid receptor antagonists. We recommend a multifaceted approach to optimizing enteral nutrition in the critical care setting which should include the early, prophylactic use of promotility agents and should focus on the management of reversible causes of impaired gastrointestinal motility.

Efficacy and Safety of Relamorelin in Diabetics With Symptoms of Gastroparesis: A Randomized, Placebo-Controlled Study

BACKGROUND & AIMS

Gastroparesis is a complication of diabetes with few treatment options. Relamorelin (also referred to as RM-131) is a selective, prokinetic agonist of ghrelin. We aimed to evaluate the efficacy of relamorelin on symptoms and gastric emptying (GE) in a 12-week, phase 2B study of diabetic patients with moderate to severe gastroparesis symptoms (DG).

METHODS

We performed a study of 393 patients with DG (37.7% male; 9.9% with type 1 diabetes; median age, 58.2 years [range 20-76]; median body mass index, 31.4 kg/m2 [range, 18.2-60.1]; HbA1c level, 7.6%, [range, 5.2-11.0]). All participants had 13C-spirulina GE breath test T1/2 values of 79 minutes or more (with 89.8% delayed relative to 90th %ile of normal, 85.75 minutes), recent vomiting, and gastroparesis cardinal symptom index-daily diary scores of 2.6 or more. Patients were randomly assigned to groups given placebo (n=104) or relamorelin (10 μg [n=98], 30 μg [n=109], or 100 μg [n=82] twice daily) for 12 weeks, following a 2-week, single-blind, placebo run-in period. Patient-reported outcomes were determined from DG Symptom Severity daily e-diaries, in which patients recorded vomiting frequency and symptom scores (nausea, abdominal pain, postprandial fullness, and bloating) on a 0-10 scale. Endpoints were change from baseline in vomiting frequency, composite DG Symptom Severity score, GE, and safety. We performed longitudinal, mixed-effects model analysis using repeated measures, with baseline and baseline-by-week interaction values as covariates.

RESULTS

Patients given relamorelin had a 75% reduction in vomiting frequency compared with baseline, but this difference was not significant compared with the placebo group. All 4 symptoms of DG (composite or individual symptoms) were significantly reduced over the 12-week study period in all 3 relamorelin dose groups compared with the placebo group (all P < .05, based on longitudinal analysis over 12 weeks). Relamorelin significantly accelerated GE from baseline compared with placebo (by 12%, P < .05 for the 10 μg and 30 μg groups; P = .051 for the 100 μg group). Dose-related worsening of glycemic control was noted in 14.5% of patients who received relamorelin; some required insulin or other diabetes drug dosage adjustments.

CONCLUSIONS

In a phase 2B randomized trial of patients with moderate to severe DG, relamorelin significantly reduced core symptoms of DG and overall composite score compared with placebo, accelerated GE, and was generally safe and well tolerated. ClinicalTrials.gov Identifier: NCT02357420.

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.

A review of pharmacotherapy for treating gastroesophageal reflux disease (GERD)

INTRODUCTION

Medical therapy of gastroesophageal reflux disease (GERD) is based on the use of proton pump inhibitors (PPIs) as first choice treatment. Despite their effectiveness, about 20-30% of patients report an inadequate response and alternative drugs are required. Areas covered: This review provides an overview of current pharmacotherapy for treating GERD by showing the results of PPIs, reflux inhibitors, antidepressants and mucosa protective medications. Expert opinion: Medical therapy of GERD does not definitely cure the disease, because even PPIs are not able to change the key factors responsible for it. However, they remain the mainstay of medical treatment, allowing us to alleviate symptoms, heal esophagitis and prevent complications in the majority of cases. Nevertheless, many patients do not respond, because acid does not play any pathogenetic role. Prokinetics and reflux inhibitors have the potential to control motor abnormalities, but the results of clinical trials are inconsistent. Antidepressant drugs are effective in specific subgroups of NERD patients with visceral hypersensitivity, but larger, controlled clinical studies are necessary. Protective drugs or medical devices have been recently adopted to reinforce mucosal resistance and preliminary trials have confirmed their efficacy either combined with or as add-on medication to PPIs in refractory patients.

Treatment options for hyperemesis gravidarum

Hyperemesis gravidarum (HG) is a severe and prolonged form of nausea and/or vomiting during pregnancy. HG affects 0.3-2% of pregnancies and is defined by dehydration, ketonuria, and more than 5% body weight loss. Initial pharmacologic treatment for HG includes a combination of doxylamine and pyridoxine. Additional interventions include ondansetron or dopamine antagonists such as metoclopramide or promethazine. The options are limited for women who are not adequately treated with these medications. We suggest that mirtazapine is a useful drug in this context and its efficacy has been described in case studies. Mirtazapine acts on noradrenergic, serotonergic, histaminergic, and muscarinic receptors to produce antidepressant, anxiolytic, antiemetic, sedative, and appetite-stimulating effects. Mirtazapine is not associated with an independent increased risk of birth defects. Further investigation of mirtazapine as a treatment for HG holds promise to expand treatment options for women suffering from HG.

Investigational drug therapies for the treatment of gastroparesis

INTRODUCTION

Gastroparesis is defined by nausea, vomiting, pain, early satiety and bloating, and characterized by delayed gastric emptying without obvious structural abnormalities. Metoclopramide is widely used, increasing gastric emptying and inhibiting nausea and vomiting. Other drugs are available in certain countries and some are used 'off-label' because they increase gastric emptying or inhibit emesis. However, correlation between gastroparesis symptoms and rates of gastric emptying is poor. For anti-emetic drugs, dose-ranging and Phase III trials in gastroparesis are lacking. Areas covered: Gastric motility may still be disordered, leading to nausea, even though gastric emptying is unchanged. One hypothesis is that interstitial cells of Cajal (ICC) are damaged by diabetes leading to gastric dysrhythmia and nausea. Novel approaches to treatment of nausea also include the use of ghrelin receptor agonists, highlighting a link between appetite and nausea. Expert opinion: There is an urgent need to diversify away from historical drug targets. In particular, there is a need to control nausea by regulating ICC functions and/or by facilitating appetite via ghrelin receptor agonists. It is also important to note that different upper gastrointestinal disorders (gastroparesis, chronic unexplained nausea and vomiting, functional dyspepsia) are difficult to distinguish apart, suggesting wider therapeutic opportunity.

Metoclopramide role in preventing ileus after cesarean, a clinical trial

PURPOSE

Ileus is a common event following cesarean section. Early post-cesarean recovery is very important not only for the mother but also for the baby who is dependent on breastfeeding. This article aims to demonstrate the efficacy of metoclopramide for the prevention of ileus after cesarean.

METHODS

In this randomized controlled trial, 696 women scheduled for cesarean were randomized in two groups. Three hundred fifty-three persons settled in control group and 343 were assigned in intervention group who received an injection of 10-mg intramuscular metoclopramide prior to operation. After cesarean, the participants recorded the first flatus, defecation, feeling of hunger, feeding and ambulation in a questionnaire, and also their sense of bloating in a visual analog scale under supervision of a research assistant. The data was analyzed by SPSS 17, t test, and chi-square, while p < 0.05 was considered significant.

RESULTS

The interval between cesarean and the first flatus (p < 0.0001), defecation (p < 0.0001), feeling of hunger (p < 0.0001), feeding (p = 0.007), and ambulation (p < 0.0001) were significantly shorter in the metoclopramide group. In addition, polytomous logistic regression analysis showed the metoclopramide group had less bloating with significant difference (OR = 2.83 and CI 1.91-4.21).

CONCLUSIONS

Our study proved the functionality of metoclopramide in preventing ileus. As this drug is safe, tolerable, harmless, inexpensive and available, and also no definite method has been developed to prevent ileus after cesarean; yet, metoclopramide could be considered as a suitable option. Certainly with regard to some limitations in our study, further comprehensive studies are still required to ensure validity of the obtained results.

Gastric emptying and glycaemia in health and diabetes mellitus

The rate of gastric emptying is a critical determinant of postprandial glycaemia and, accordingly, is fundamental to maintaining blood glucose homeostasis. Disordered gastric emptying occurs frequently in patients with longstanding type 1 diabetes mellitus and type 2 diabetes mellitus (T2DM). A complex bidirectional relationship exists between gastric emptying and glycaemia--gastric emptying accounts for ∼35% of the variance in peak postprandial blood glucose concentrations in healthy individuals and in patients with diabetes mellitus, and the rate of emptying is itself modulated by acute changes in glycaemia. Clinical implementation of incretin-based therapies for the management of T2DM, which diminish postprandial glycaemia, in part by slowing gastric emptying, is widespread. Other therapies for patients with T2DM, which specifically target gastric emptying include pramlintide and dietary-based treatment approaches. A weak association exists between upper gastrointestinal symptoms and the rate of gastric emptying. In patients with severe diabetic gastroparesis, pathological changes are highly variable and are characterized by loss of interstitial cells of Cajal and an immune infiltrate. Management options for patients with symptomatic gastroparesis remain limited in their efficacy, which probably reflects the heterogeneous nature of the underlying pathophysiology.

Molecular perspectives on solid-state phase transformation and chemical reactivity of drugs: metoclopramide as an example

Here, I provide an overview of the solid-state characteristics, phase transformations and chemical reactions of metoclopramide hydrochloride monohydrate (MCP HCl H2O). Three unique techniques, including thermoanalytical methods, one-step simultaneous differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) microspectroscopy, and hot-stage microscopic (HSM) imaging, have been applied to study the solid-state phase transitions of MCP HCl H2O in continuous dehydration, amorphization and recrystallization processes. I also review the effects of grinding or heating on ion-exchange reactions, milling, compression or colyophilization on Maillard reactions, and γ-ray irradiation or electron beams on radiolysis in the solid state. I also report the exposure of MCP HCl H2O in solution to light, irradiation, oxidants or π-acceptors. This review will serve as a useful keynote for the evolving realm of solid-state chemistry research.

Drugs acting at 5-HT4 , D2 , motilin, and ghrelin receptors differ markedly in how they affect neuromuscular functions in human isolated stomach

BACKGROUND

Progress in identifying safer, effective drugs to increase gastric emptying is impeded by failed clinical trials. One potential reason for failure is lack of translation from animal models to the human condition. To make progress, the actions of existing drugs and new therapeutic candidates need to be understood in human isolated stomach.

METHODS

Neuromuscular activities were evoked in human gastric antrum circular muscle by electrical field stimulation (EFS), defined phenotypically using pharmacological tools.

KEY RESULTS

EFS evoked cholinergically mediated contractions, attenuated by simultaneous nitrergic activation. The 5-HT4 receptor agonist/D2 antagonist metoclopramide and the selective 5-HT4 agonist prucalopride, facilitated contractions in the absence (respectively, Emax 95 ± 29% and 42 ± 9%, n = 3-6 each concentration) and presence (139 ± 38%, 55 ± 13%, n = 3-5) of the NO synthase inhibitor L-NAME, without affecting submaximal contractions to carbachol; the 5-HT4 antagonist SB204070 prevented facilitation by metoclopramide 100 μM (respectively, -5 (range -26 to 34) and 167 (12-1327)% in presence and absence; n = 5-6). The selective motilin receptor agonist camicinal provided considerably greater facilitation (478 (12-2080)% at 30 μM, n = 8). Domperidone (0.001-100 μM; n = 3-6) and acylated or des-acylated ghrelin (1-300 nM; n = 2-4) had no consistent activity, even with protease inhibitors.

CONCLUSIONS & INFERENCES

5-HT4 receptor agonists show different efficacies. Motilin receptor activation has greater potential to increase gastric emptying, whereas ghrelin and D2 receptor antagonism have no direct activity. Drugs stimulating human gastric motility directly can act regardless of disease mechanisms, whereas drugs without direct activity but an ability to block nausea/vomiting may be effective only if these symptoms exist.

Tardive dyskinesia: therapeutic options for an increasingly common disorder

Tardive dyskinesia (TD) is a serious, often disabling, movement disorder that is caused by medications that block dopamine receptors (i.e., neuroleptics, anti-emetics). There is currently no standard treatment approach for physicians confronted with such patients. This may be the result of notions that TD is disappearing because of the switch to second-generation antipsychotic agents and that it is largely reversible. In this article we demonstrate that second-generation antipsychotics do, indeed, cause TD and, in fact, the frequency is likely higher than expected because of growing off-label uses and a tripling of prescriptions written in the last 10 years. In addition, studies demonstrate that TD actually remits in only a minority of patients when these drugs are withdrawn. Furthermore, neuroleptic agents are often utilized to treat TD, despite prolonged exposure being a risk factor for irreversibility. The outcome of these trends is a growing population afflicted with TD. We review non-neuroleptic agents that have shown positive results in small, early-phase, blinded trials, including tetrabenazine, amantadine, levetiracetam, piracetam, clonazepam, propranolol, vitamin B6, and Ginkgo biloba. Other options, such as botulinum toxin and deep brain stimulation, will also be discussed, and a suggested treatment algorithm is provided. While these agents are reasonable treatment options at this time there is a need, with a concerted effort between neurology and psychiatry, for full-scale drug development, including multicenter, randomized, blinded trials to confirm the effectiveness of the agents that were positive in phase 2 trials and the development of newer ones.

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.

Chinese herbal medicine banxiaxiexin decoction treating diabetic gastroparesis: a systematic review of randomized controlled trials

Objective. To assess the current clinical evidence of Banxiaxiexin decoction for diabetic gastroparesis (DGP). Methods. Electronic databases were searched until December 2012. No language limitations were applied. We included RCTs using Banxiaxiexin decoction/modified Banxiaxiexin decoction for DGP. No restriction for the control group except acupuncture. Applying clinical effective rate as the main outcome index. Data extraction, analyses and quality assessment were conducted according to the Cochrane review standards. Results. 16 RCTs involving 1302 patients were finally identified, and the methodological quality was evaluated as generally low. The data showed that the effect of Banxiaxiexin decoction (BXXD) for DGP was superior to the control group (n = 1302, RR 1.23, 95% CI 1.17 to 1.29, Z = 8.04, P < 0.00001). Only one trial recorded adverse events, no obvious adverse event occurred. Conclusions. Banxiaxiexin decoction could regain the gastric emptying rate and improve diabetic gastrointestinal symptoms. However, the methodological quality of included studies is low, and long term efficacy and safety are still uncertain, which indicates that the findings above should be read with caution. Thereby, well-designed, large-scale, and high-quality randomized controlled clinical trials with scientific rigor are warranted for stronger evidence in future research.

Pathophysiology and pharmacotherapy of gastroparesis: current and future perspectives

INTRODUCTION

Gastroparesis is an important clinical disorder characterised by delayed gastric emptying in the absence of mechanical outlet obstruction. Idiopathic, diabetes and postsurgical causes represent the most common aetiologies. The condition commonly manifests as upper gastrointestinal symptoms, including nausea, vomiting, postprandial fullness, early satiety, abdominal pain and bloating.

AREAS COVERED

This paper provides a review of the prevalence, pathophysiology and clinical features associated with gastroparesis, with a particular focus on current pharmacological management options and novel and emerging therapies. A literature search was undertaken using the search terms: gastroparesis, diabetic gastroparesis, idiopathic gastroparesis, gastric emptying, prokinetic, metoclopramide, domperidone, erythromycin, motilin, alemcinal, KC11458, mitemcinal, ghrelin, TZP-101, TZP-102, RM-131, tegaserod, prucalopride, naronapride, velusetrag, levosulpiride, itopride, botulinum toxin, gastric electrical stimulation, Enterra.

EXPERT OPINION

Strategies for the management of gastroparesis include correction of malnutrition, dehydration and electrolyte imbalance, relief of symptoms by appropriate use of prokinetic and antiemetic agents and, in patients with gastroparesis associated with diabetes or critical illness-induced hyperglycaemia, optimisation of glycaemic control. Conventional prokinetic agents form the mainstay of treatment. While novel pharmacotherapies are in development, compelling evidence for their efficacy, particularly in symptom relief, remains to be established.

Tardive and spontaneous dyskinesia incidence in the general population

BACKGROUND

To identify the incidence rate of spontaneous dyskinesia (SD) and tardive dyskinesia (TD) in a general population and to examine the association between dykinesia and potential risk factors (exposure to metoclopramide [MCP], antipsychotic drugs, and history of diabetes and psychoses).

METHODS

A retrospective cohort study was conducted for the years 2001 through 2010, based on medical claims data from the Deseret Mutual Benefit Administrators (DMBA).

RESULTS

Thirty-four cases of TD and 229 cases of SD were identified. The incidence rate of TD among persons previously prescribed an antipsychotic or metoclopramide (MCP) (per 1,000) was 4.6 (1.6-7.7) for those with antipsychotic drug use only, 8.5 (4.8-12.2) for those with MCP use only, and 15.0 (2.0-28.1) for those with both antipsychotic and MCP use. In the general population, the incidence rate (per 100,000 person-years) of TD was 4.3 and of probable SD was 28.7. The incidence rates of TD and SD increased with age and were greater for females. Those with diabetes or psychoses had almost a 3-fold greater risk of TD than those without either of these diseases. Persons with schizophrenia had 31.2 times increased risk of TD than those without the disease. Positive associations also existed between the selected diseases and the incidence rate of probable SD, with persons with schizophrenia having 4.4 times greater risk of SD than those without the disease.

CONCLUSIONS

SD and TD are rare in this general population. Diabetes, psychoses, and especially schizophrenia are positively associated with SD and TD. A higher proportion of those with SD present with spasm of the eyelid muscles (blepharospasm) compared more with the TD cases who present more with orofacial muscular problems.