Population Pharmacokinetics of Metoclopramide in Infants, Children, and Adolescents

Pharmacokinetics of Dexamethasone in Children and Adolescents with Obesity

Dexamethasone is a synthetic glucocorticoid approved for treating disorders of various organ systems in both adult and pediatric populations. Currently, approved pediatric dosing recommendations are weight-based, but it is unknown whether differences in dexamethasone drug disposition and exposure exist for children with obesity. This study aimed to develop a population pharmacokinetic (PopPK) model for dexamethasone with data collected from children with obesity. Dexamethasone was given as either IV or oral/enteral administration, and a salt factor correction was used for dexamethasone sodium phosphate injection. A PopPK analysis using dexamethasone plasma concentration versus time was performed using the software NONMEM. A virtual population of 1000 children with obesity across three age groups was generated for dosing simulations. Data from 59 study participants with 82 PK plasma samples were used in the PopPK analysis. A one-compartment model with first-order absorption and the inclusion of total body weight as a covariate characterized the data. No other covariates were included in the PopPK model. Single and multiple IV dose(s) of 0.5 and 1 mg/kg every 8 h resulted in 68% or more of virtual children with obesity attaining simulated exposures that were within exposure ranges previously reported in adult studies. In conclusion, this was the first study to characterize dexamethasone's PopPK in children with obesity. Simulation results suggest that virtual children with obesity receiving oral doses of 0.5 and 1 mg/kg had generally comparable dexamethasone exposures as adult estimates. Additional studies are needed to characterize the dexamethasone's target exposure in children.

Review of Dopamine Antagonists for Nausea and Vomiting in Palliative Care Patients

Symptoms of nausea and vomiting are common in palliative care and hospice patients. One of the many classes of medications used for the treatment of nausea and vomiting is dopamine receptor antagonists which are particularly helpful for treating nausea mediated by the chemoreceptor trigger zone (CTZ) and impaired gastrointestinal function. While dopamine antagonists can be very effective treatments for nausea they should be used with caution as they carry the risk of QTc prolongation, have a FDA black box warning for tardive dyskinesia (TD), and increased risk of precipitating psychosis and death in patients with dementia. This review will cover haloperidol, olanzapine, prochlorperazine, and metoclopramide for treatment of nausea and vomiting including evidence of efficacy, pharmacokinetics, and pharmacodynamics to improve safe and effective utilization in clinical practice. This includes medication receptor site affinities at histaminic, muscarinic, serotonergic, and alpha-adrenergic receptors which can help providers anticipate potential adverse effects and risk of extrapyramidal symptoms (EPS), TD, and QTc prolongation. This review also includes considerations for dose adjustments based on renal function, hepatic function, and age. Understanding the pharmacology of dopamine antagonists can help providers choose the best treatment for control of nausea and vomiting and subsequently improve patients' quality of life.

Comparison of the Effects of Govarcin Herbal Capsule and Metoclopramide for Alleviating Gastrointestinal Symptoms in Patients with Functional Dyspepsia: A Randomized Double-blind Clinical Trial

BACKGROUND

Functional dyspepsia (FD) is felt as a discomfort or pain on the center line or upper abdomen. In this study, we aimed to compare the effects of Govarcin herbal capsule and Metoclopramide for alleviating gastrointestinal symptoms in patients with FD.

METHODS

Totally, 106 patients enrolled in a double-blind, clinical trial study. The participants had FD and were divided into two groups receiving Govarcin and Metoclopramide by block randomization. The patients were treated for four weeks, taking one Govarcin capsule or Metoclopramide tablet after each meal. The rate of improvement in patients was assessed by mitigation of clinical symptoms, including epigastric pain, fullness, discomfort, nausea, vomiting and heartburn. Also, before and after intervention, we used Nepin questionnaire and ROME III. SPSS statistics 25 software was used for data analyzing.

RESULTS

Clinical symptom score changes between Govarcin and Metoclopramide patients' groups showed that there was no significant difference in any of the clinical symptom scores (except for heartburn, p-value=0.012) between the study groups. Nepean score in Govarcin group before and after treatment were 19.3±4.8 and 8.9±2.8, respectively (p-value<0.001). For Metoclopramide group, these values were 19.8±3.5 and 9.4±2.1 respectively (p-value<0.001). No significant difference was found in terms of Nepean score between the Govarcin and Metoclopramide groups (p-value=0.995).

CONCLUSION

Govarcin herbal capsule can be used to remedy symptoms in patients with FD. It seems that Govarcin is as effective as Metoclopramide in fighting symptoms of FD as no significant difference in efficacy has been demonstrated between them.

Case report: metoclopramide induced acute dystonic reaction in adolescent CYP2D6 poor metabolizers

Metoclopramide is indicated for the management of gastroesophageal reflux, gastric stasis, nausea, and vomiting. Metoclopramide-induced acute dystonic reactions (MIADRs), along with repetitive involuntary protrusion of the tongue, are well-known phenomena in children and young adults that may appear after the first dose. The drug is primarily metabolized via oxidation by the cytochrome P450 enzyme CYP2D6 and to a lesser extent by CYP3A4 and CYP1A2. A recommendation to decrease metoclopramide dosing in patients with severely limited to no CYP2D6 activity (i.e., poor metabolizers, PMs) is included in the drug label. It is important to note, however, that a requirement or recommendation for pre-emptive testing for CYP2D6 metabolizer status is not included in the drug label. We present two cases of acute dystonia in two non-consanguineous male adolescents: one following metoclopramide and cimetidine administration in a 14-year-old to treat gastroesophageal reflux, and another following metoclopramide and pantoprazole administration in a 17-year-old with acute gastroenteritis. A retrospective pharmacogenetic analysis revealed both patients as CYP2D6 PMs.

Gut dysmotility in children with neurological impairment: the nutritional management

Intestinal motility disorders represent a frequent problem in children with neurological impairment. These conditions are characterized by abnormal movements of the gut, which can result in symptoms such as constipation, diarrhea, reflux, and vomiting. The underlying mechanisms leading to dysmotility are various, and the clinical manifestations are often nonspecific. Nutritional management is an important aspect of care for children with gut dysmotility, as it can help to improve their quality of life. Oral feeding, when safe and in the absence of risk of ingestion or severe dysphagia, should always be encouraged. When oral nutrition is insufficient or potentially harmful, it is necessary to switch to an enteral by tube or parenteral nutrition before the onset of malnutrition. In most cases, children with severe gut dysmotility may require feeding via a permanent gastrostomy tube to ensure adequate nutrition and hydration. Drugs may be necessary to help manage gut dysmotility, such as laxatives, anticholinergics and prokinetic agents. Nutritional management of patients with neurological impairment often requires an individualized care plan to optimize growth and nutrition and to improve overall health outcomes. This review tries to sum up most significant neurogenetic and neurometabolic disorders associated with gut dysmotility that may require a specific multidisciplinary care, identifying a proposal of nutritional and medical management.

External Evaluation of Risperidone Population Pharmacokinetic Models Using Opportunistic Pediatric Data

Risperidone is approved to treat schizophrenia in adolescents and autistic disorder and bipolar mania in children and adolescents. It is also used off-label in younger children for various psychiatric disorders. Several population pharmacokinetic models of risperidone and 9-OH-risperidone have been published. The objectives of this study were to assess whether opportunistically collected pediatric data can be used to evaluate risperidone population pharmacokinetic models externally and to identify a robust model for precision dosing in children. A total of 103 concentrations of risperidone and 112 concentrations of 9-OH-risperidone, collected from 62 pediatric patients (0.16–16.8 years of age), were used in the present study. The predictive performance of five published population pharmacokinetic models (four joint parent-metabolite models and one parent only) was assessed for accuracy and precision of the predictions using statistical criteria, goodness of fit plots, prediction-corrected visual predictive checks (pcVPCs), and normalized prediction distribution errors (NPDEs). The tested models produced similarly precise predictions (Root Mean Square Error [RMSE]) ranging from 0.021 to 0.027 nmol/ml for risperidone and 0.053–0.065 nmol/ml for 9-OH-risperidone). However, one of the models (a one-compartment mixture model with clearance estimated for three subpopulations) developed with a rich dataset presented fewer biases (Mean Percent Error [MPE, %] of 1.0% vs. 101.4, 146.9, 260.4, and 292.4%) for risperidone. In contrast, a model developed with fewer data and a more similar population to the one used for the external evaluation presented fewer biases for 9-OH-risperidone (MPE: 17% vs. 69.9, 47.8, and 82.9%). None of the models evaluated seemed to be generalizable to the population used in this analysis. All the models had a modest predictive performance, potentially suggesting that sources of inter-individual variability were not entirely captured and that opportunistic data from a highly heterogeneous population are likely not the most appropriate data to evaluate risperidone models externally.