Pharmacokinetics and tolerability of rabeprazole in children 1 to 11 years old with gastroesophageal reflux disease

Safety of Proton Pump Inhibitors in Pediatric Population: A Systematic Review

Objective. Commonly recommended drugs for adults and children include proton pump inhibitors (PPIs), proven effective for treating peptic diseases like stomach ulcers, GERD, and Helicobacter pylori infections in children over 1-year-old. Yet, prolonged PPI use carries higher risks of adverse reactions, prompting this study's analysis. Methods. We have performed a systematic review of 30 articles, which include a total of 762 505 pediatric patients. Results. Adverse effects were encountered in 6.98% of the population. The 5 most common adverse effects were respiratory tract complications, gastrointestinal complications, urinary tract infections, asthma, and ENT infections. Conclusion. Hence, PPIs should be prescribed only when necessary, and physicians should prioritize patient education when considering their use.

Production of an O-desmethylated product, a major human metabolite, of rabeprazole sulfide by bacterial P450 enzymes

Rabeprazole is a common type of proton pump inhibitor (PPI) used to treat various peptic disorders. Unlike most PPI drugs, rabeprazole is spontaneously reduced to rabeprazole sulfide (thioether) when it is given to patients. As a result, rabeprazole sulfide is considered one of the active metabolites of rabeprazole. Rabeprazole sulfide is mainly metabolized to desmethyl rabeprazole sulfide by CYP2C19 and CYP2D6 in people. However, the pharmacological efficacy and safety of desmethyl rabeprazole sulfide have not yet been investigated. Its usage is challenging due to the high cost associated with the drug. In this study, we found CYP102A1 mutants that can produce desmethyl rabeprazole sulfide as a major metabolite of rabeprazole sulfide. The chemical characteristics of the major product were confirmed using high-performance liquid chromatography, LC-mass spectrometry, and nuclear magnetic resonance spectroscopy. CYP102A1 mutants R47L/F87V/L188Q, R47L/F87V/L188Q/A335V/Q359R, and R47L/F87V/L188Q/I254V/D351E showed kcat values of 39, 93, and 88 min-1, respectively, for O-desmethylation of rabeprazole sulfide. Furthermore, the highest concentration of desmethyl rabeprazole sulfide product from 2 mM rabeprazole sulfide at optimal conditions was obtained in bacterial whole-cell biotransformation with the R47L/F87V/L188Q mutant, reaching 0.63 mM at 4-h incubation. In conclusion, we present a platform that facilitates the efficient and sustainable production of the desmethylated product from rabeprazole sulfide for use in the biopharmaceutical industry.

Pharmacological treatment of gastro-oesophageal reflux in children

BACKGROUND

Gastro-oesophageal reflux (GOR) is characterised by the regurgitation of gastric contents into the oesophagus. GOR is a common presentation in infancy, both in primary and secondary care, affecting approximately 50% of infants under three months old. The natural history of GOR in infancy is generally of a self-limiting condition that improves with age, but older children and children with co-existing medical conditions can have more protracted symptoms. The distinction between gastro-oesophageal reflux disease (GORD) and GOR is debated. Current National Institute of Health and Care Excellence (NICE) guidelines define GORD as GOR causing symptoms severe enough to merit treatment. This is an update of a review first published in 2014.

OBJECTIVES

To assess the effects of pharmacological treatments for GOR in infants and children.

SEARCH METHODS

For this update, we searched CENTRAL, MEDLINE, Embase, and Web of Science up to 17 September 2022. We also searched for ongoing trials in clinical trials registries, contacted experts in the field, and searched the reference lists of trials and reviews for any additional trials.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) that compared any currently-available pharmacological treatment for GOR in children with placebo or another medication. We excluded studies assessing dietary management of GORD and studies of thickened feeds. We included studies in infants and children up to 16 years old.

DATA COLLECTION AND ANALYSIS

We used standard methodology expected by Cochrane.

MAIN RESULTS

We included 36 RCTs involving 2251 children and infants. We were able to extract summary data from 14 RCTs; the remaining trials had insufficient data for extraction. We were unable to pool results in a meta-analysis due to methodological differences in the included studies (including heterogeneous outcomes, study populations, and study design). We present the results in two groups by age: infants up to 12 months old, and children aged 12 months to 16 years old. Infants Omeprazole versus placebo: there is no clear effect on symptoms from omeprazole. One study (30 infants; very low-certainty evidence) showed cry/fuss time in infants aged three to 12 months had altered from 246 ± 105 minutes/day at baseline (mean +/- standard deviation (SD)) to 191 ± 120 minutes/day in the omeprazole group and from 287 ± 132 minutes/day to 201 ± 100 minutes/day in the placebo group (mean difference (MD) 10 minutes/day lower (95% confidence interval (CI) -89.1 to 69.1)). The reflux index changed in the omeprazole group from 9.9 ± 5.8% in 24 hours to 1.0 ± 1.3% and in the placebo group from 7.2 ± 6.0% to 5.3 ± 4.9% in 24 hours (MD 7% lower, 95% CI -4.7 to -9.3). Omeprazole versus ranitidine: one study (76 infants; very low-certainty evidence) showed omeprazole may or may not provide symptomatic benefit equivalent to ranitidine. Symptom scores in the omeprazole group changed from 51.9 ± 5.4 to 2.4 ± 1.2, and in the ranitidine group from 47 ± 5.6 to 2.5 ± 0.6 after two weeks: MD -4.97 (95% CI -7.33 to -2.61). Esomeprazole versus placebo: esomeprazole appeared to show no additional reduction in the number of GORD symptoms compared to placebo (1 study, 52 neonates; very low-certainty evidence): both the esomeprazole group (184.7 ± 78.5 to 156.7 ± 75.1) and placebo group (183.1 ± 77.5 to 158.3 ± 75.9) improved: MD -3.2 (95% CI -4.6 to -1.8). Children Proton pump inhibitors (PPIs) at different doses may provide little to no symptomatic and endoscopic benefit. Rabeprazole given at different doses (0.5 mg/kg and 1 mg/kg) may provide similar symptom improvement (127 children in total; very low-certainty evidence). In the lower-dose group (0.5 mg/kg), symptom scores improved in both a low-weight group of children (< 15 kg) (mean -10.6 ± SD 11.13) and a high-weight group of children (> 15 kg) (mean -13.6 ± 13.1). In the higher-dose groups (1 mg/kg), scores improved in the low-weight (-9 ± 11.2) and higher-weight groups (-8.3 ± 9.2). For the higher-weight group, symptom score mean difference between the two different dosing regimens was 2.3 (95% CI -2 to 6.6), and for the lower-weight group, symptom score MD was 4.6 (95% CI -2.9 to 12). Pantoprazole: pantoprazole may or may not improve symptom scores at 0.3 mg/kg, 0.6 mg/kg, and 1.2 mg/kg pantoprazole in children aged one to five years by week eight, with no difference between 0.3 mg/kg and 1.2 mg/kg dosing (0.3 mg/kg mean -2.4 ± 1.7; 1.2 mg/kg -1.7 ± 1.2: MD 0.7 (95% CI -0.4 to 1.8)) (one study, 60 children; very low-certainty evidence). There were insufficient summary data to assess other medications.

AUTHORS' CONCLUSIONS

There is very low-certainty evidence about symptom improvements and changes in pH indices for infants. There are no summary data for endoscopic changes. Medications may or may not provide a benefit (based on very low-certainty evidence) for infants whose symptoms remain bothersome, despite nonmedical interventions or parental reassurance. If a medication is required, there is no clear evidence based on summary data for omeprazole, esomeprazole (in neonates), H₂antagonists, and alginates for symptom improvements (very low-certainty evidence). Further studies with longer follow-up are needed. In older children with GORD, in studies with summary data extracted, there is very low-certainty evidence that PPIs (rabeprazole and pantoprazole) may or may not improve GORD outcomes. No robust data exist for other medications. Further RCT evidence is required in all areas, including subgroups (preterm babies and children with neurodisabilities).

An O-Demethylation Metabolite of Rabeprazole Sulfide by Cunninghamella blakesleeana 3.970 Biotransformation

To explore the potential metabolites from rabeprazole sulfide, seven strains of filamentous fungi were screened for their biotransformation abilities. Among these strains, Cunninghamella blakesleeana 3.970 exhibited the best result. Four different culture media were screened in order to identify the most optimal for subsequent research. Single factors such as the initial pH of culture media, culture time, inoculation volume, and media volume were individually investigated to provide the optimum biotransformation conditions. Then, an orthogonal optimization process using a five-factor, four-level L16(45) experiment was designed and performed. Finally, when the substrate concentration is 3 g/L, one major metabolite was detected with a transformation rate of 72.4%. Isolated by semipreparative HPLC, this metabolite was further detected by ESI-MS and NMR. The final data analysis indicated that the metabolite is O-demethylation rabeprazole sulfide.

Population pharmacokinetics of rabeprazole and dosing recommendations for the treatment of gastroesophageal reflux disease in children aged 1-11 years

BACKGROUND AND OBJECTIVE

Rabeprazole sodium is a proton pump inhibitor used for the treatment of gastroesophageal reflux disease (GERD). The objective of this study was to develop a population pharmacokinetic model for rabeprazole that describes concentration-time data arising from phase I and phase III studies in adult and pediatric subjects, including neonates and preterm infants, and propose dosing recommendations for pediatric subjects aged 1-11 years.

METHODS

A total of 4,417 pharmacokinetic observations from 597 subjects aged 6 days to 55.7 years with body weights of 1.15-100 kg were used to develop the population pharmacokinetic model using non-linear mixed-effects modeling techniques. Weight and age were included in the structural model to describe clearance (CL) and central volume of distribution (V c). Other covariates considered during model development included sex, race, creatinine clearance, hepatic function, formulation, feeding status, and route of administration. The final model was used to determine doses for pediatric subjects aged 1-11 years to achieve a steady-state area under the plasma concentration-time curve across the dose interval of 24 h (AUC24) within the target adult AUC24 range obtained following a rabeprazole 10 mg dose.

RESULTS

The best model was a two-compartment disposition model with a sequential zero-order duration of input (Dur), first-order absorption (k a) following a lag time (T lag), with weight and age effects on CL and V c. Formulation type and feeding status described some of the variability in bioavailability and the absorption parameters T lag, Dur, and k a. A dosage regimen of 5 mg once daily for children <15 kg, and 10 mg for children ≥15 kg is recommended for 1- to 11-year-old pediatric patients with GERD.

CONCLUSIONS

The pharmacokinetics of rabeprazole were described with good precision following administration of rabeprazole across a range of doses and in a range of formulations.

Adverse effects reported in the use of gastroesophageal reflux disease treatments in children: a 10 years literature review

Gastroesophageal reflux (GER) is commonly observed in children, particularly during the first year of life. Pharmacological therapy is mostly reserved for symptomatic infants diagnosed with GER disease (GERD), usually as defined in a recent consensus statement. The purpose of the present article was to review the reported adverse effects of pharmacological agents used in the treatment of paediatric GERD. We conducted this review using the electronic journal database Pubmed and Cochrane database systematic reviews using the latest 10-year period (1 January 2003 to 31 December 2012). Our search strategy included the following keywords: omeprazole, esomeprazole, lansoprazole, pantoprazole, rabeprazole, rantidine, cimetidine, famotidine, nizatidine, domperidone, metoclopramide, betanechol, erythromycin, baclofen, alginate. We used Pubmed's own filter of: 'child: birth-18 years'. All full articles were reviewed and we only included randomized controlled trials retrieved from our search. We addressed a summary of our search on a drug-by-drug basis with regard to its mechanism of action and clinical applications, and reviewed all of the adverse effects reported and the safety profile of each drug. Adverse effects have been reported in at least 23% of patients treated with histamine H2 receptor antagonists (H2 RAs) and 34% of those treated with proton pump inhibitors (PPIs), and mostly include headaches, diarrhoea, nausea (H2 RAs and PPIs) and constipation (PPIs). Acid suppression may place immune-deficient infants and children, or those with indwelling catheters, at risk for the development of lower respiratory tract infections and nosocomial sepsis. Prokinetic agents have many adverse effects, without major benefits to support their routine use.

Pharmacokinetics and safety of dexlansoprazole MR in pediatric patients with symptomatic gastroesophageal reflux disease

OBJECTIVE

To evaluate the safety and pharmacokinetic profile of dexlansoprazole modified-release (MR) capsules in pediatric patients with symptomatic gastroesophageal reflux disease (GERD).

METHODS

This Phase I, open-label study enrolled male and female patients (1 to 11 years of age) with GERD. Patients received dexlansoprazole MR 15 mg, 30 mg, or 60 mg (according to weight) once daily for 7 days. Blood samples for the measurement of plasma dexlansoprazole concentrations were collected for 24 hours after the day 7 dose. Dexlansoprazole plasma concentrations and pharmacokinetic parameters were summarized by dose group. Safety assessments included adverse events (AEs), clinical laboratory evaluations, fasting gastrin concentrations, physical examinations, electrocardiograms, and vital signs.

RESULTS

Thirty-six patients received study drug (12 per dose group), and 31 had evaluable pharmacokinetic data. There was a significant effect of weight on dose-normalized area under the curve (AUC, P=0.003) and dose-normalized maximum plasma concentration (Cmax) (P=0.013), indicating that for a given dose, dexlansoprazole exposure decreases as body weight increases. After adjusting for body weight, both dexlansoprazole Cmax and AUC increased in an approximately dose-proportional manner with increasing dexlansoprazole dose. A total of ten of 36 patients reported at least one treatment-emergent AE, with most events considered mild in intensity. The most common AEs were vomiting, abdominal pain, diarrhea, and nausea.

CONCLUSION

In 1- to 11-year-old patients with symptomatic GERD, weight-adjusted dexlansoprazole AUC and Cmax increased approximately dose-proportionally. However, for a given dose, dexlansoprazole exposure decreased with increasing body weight. Dexlansoprazole MR was well tolerated, and the incidence of AEs did not increase with increasing dose.

Pharmacological treatment of children with gastro-oesophageal reflux

BACKGROUND

Gastro-oesophageal reflux (GOR) is a common disorder, characterised by regurgitation of gastric contents into the oesophagus. GOR is a very common presentation in infancy in both primary and secondary care settings. GOR can affect approximately 50% of infants younger than three months old (Nelson 1997). The natural history of GOR in infancy is generally that of a functional, self-limiting condition that improves with age; < 5% of children with vomiting or regurgitation continue to have symptoms after infancy (Martin 2002). Older children and children with co-existing medical conditions can have a more protracted course. The definition of gastro-oesophageal reflux disease (GORD) and its precise distinction from GOR are debated, but consensus guidelines from the North American Society of Gastroenterology, Hepatology and Nutrition (NASPGHAN-ESPGHAN guidelines 2009) define GORD as 'troublesome symptoms or complications of GOR.'

OBJECTIVES

This Cochrane review aims to provide a robust analysis of currently available pharmacological interventions used to treat children with GOR by assessing all outcomes indicating benefit or harm.

SEARCH METHODS

We sought to identify relevant published trials by searching the Cochrane Central Register of Controlled Trials (CENTRAL) (2014, Issue 5), MEDLINE and EMBASE (1966 to 2014), the Centralised Information Service for Complementary Medicine (CISCOM), the Institute for Scientific Information (ISI) Science Citation Index (on BIDS-UK General Science Index) and the ISI Web of Science. We also searched for ongoing trials in the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com).Reference lists from trials selected by electronic searching were handsearched for relevant paediatric studies on medical treatment of children with gastro-oesophageal reflux, as were published abstracts from conference proceedings (published in Gut and Gastroenterology) and reviews published over the past five years.No language restrictions were applied.

SELECTION CRITERIA

Abstracts were reviewed by two review authors, and relevant RCTs on study participants (birth to 16 years) with GOR receiving a pharmacological treatment were selected. Subgroup analysis was considered for children up to 12 months of age, and for children 12 months to 16 years of age, and for those with neurological impairment.

DATA COLLECTION AND ANALYSIS

Trials were critically appraised and data collected by two review authors. Risk of bias was assessed. Meta-analysis data were independently extracted by two review authors, and suitable outcome data were analysed using RevMan.

MAIN RESULTS

A total of 24 studies (1201 participants) contributed data to the review. The review authors had several concerns regarding the studies. Pharmaceutical company support for manuscript preparation was a common feature; also, because common endpoints were lacking, study populations were heterogenous and variations in study design were noted, individual drug meta-analysis was not possible.Moderate-quality evidence from individual studies suggests that proton pump inhibitors (PPIs) can reduce GOR symptoms in children with confirmed erosive oesophagitis. It was not possible to demonstrate statistical superiority of one PPI agent over another.Some evidence indicates that H₂antagonists are effective in treating children with GORD. Methodological differences precluded performance of meta-analysis on individual agents or on these agents as a class, in comparison with placebo or head-to-head versus PPIs, and additional studies are required.RCT evidence is insufficient to permit assessment of the efficacy of prokinetics. Given the diversity of study designs and the heterogeneity of outcomes, it was not possible to perform a meta-analysis of the efficacy of domperidone.In younger children, the largest RCT of 80 children (one to 18 months of age) with GOR showed no evidence of improvement in symptoms and 24-hour pH probe, but improvement in symptoms and reflux index was noted in a subgroup treated with domperidone and co-magaldrox(Maalox(®) ). In another RCT of 17 children, after eight weeks of therapy. 33% of participants treated with domperidone noted an improvement in symptoms (P value was not significant). In neonates, the evidence is even weaker; one RCT of 26 neonates treated with domperidone over 24 hours showed that although reflux frequency was significantly increased, reflux duration was significantly improved.Diversity of RCT evidence was found regarding efficacy of compound alginate preparations(Gaviscon Infant(®) ) in infants, although as a result of these studies, Gaviscon Infant(®) was changed to become aluminium-free and has been assessed in its current form in only two studies since 1999. Given the diversity of study designs and the heterogeneity of outcomes, as well as the evolution in formulation, it was not possible to perform a meta-analysis on the efficacy of Gaviscon Infant(®) . Moderate evidence indicates that Gaviscon Infant(®) improves symptoms in infants, including those with functional reflux; the largest study of the current formulation showed improvement in symptom control but was limited by length of follow-up.No serious side effects were reported.No RCTs on pharmacological treatments for children with neurodisability were identified.

AUTHORS' CONCLUSIONS

Moderate evidence was found to support the use of PPIs, along with some evidence to support the use of H₂ antagonists in older children with GORD, based on improvement in symptom scores, pH indices and endoscopic/histological appearances. However, lack of independent placebo-controlled and head-to-head trials makes conclusions as to relative efficacy difficult to determine. Further RCTs are recommended. No robust RCT evidence is available to support the use of domperidone, and further studies on prokinetics are recommended, including assessments of erythromycin.Pharmacological treatment of infants with reflux symptoms is problematic, as many infants have GOR, and little correlation has been noted between reported symptoms and endoscopic and pH findings. Better evidence has been found to support the use of PPIs in infants with GORD, but heterogeneity in outcomes and in study design impairs interpretation of placebo-controlled data regarding efficacy. Some evidence is available to support the use of Gaviscon Infant(®) , but further studies with longer follow-up times are recommended. Studies of omeprazole and lansoprazole in infants with functional GOR have demonstrated variable benefit, probably because of differences in inclusion criteria.No robust RCT evidence has been found regarding treatment of preterm babies with GOR/GORD or children with neurodisabilities. Initiation of RCTs with common endpoints is recommended, given the frequency of treatment and the use of multiple antireflux agents in these children.

Pharmacokinetics of rabeprazole granules versus tablets, and the effect of food on the pharmacokinetics of rabeprazole granules in healthy adults-cross-study comparison

The primary objective was to compare the pharmacokinetics (PK) of rabeprazole granules versus rabeprazole tablets, and assess the effect of food on the PK of rabeprazole granules. Data from three phase 1, open-label, single-dose, randomized, crossover studies in healthy adult participants are presented separately and as a cross-study comparison; study 1: PK of phase 1 rabeprazole granules versus rabeprazole tablets under fasting conditions; study 2: PK of phase 3 rabeprazole granules versus phase 1 rabeprazole granules; study 3: bioequivalence of to-be-marketed rabeprazole granules (sprinkle capsules) versus phase 3 rabeprazole granules; and assessment of the food effect for the to-be-marketed rabeprazole granules. Overall, 123 of 130 participants enrolled completed the studies. The overall plasma exposure as measured by area under the plasma concentration-time curve (AUC) was comparable between rabeprazole granules and tablets; mean peak plasma concentration (Cmax ) was lower for the granules compared with tablets. The plasma elimination half-life was short and independent of formulation. Food intake prior to administration of the to-be-marketed granules delayed the absorption and reduced the estimated parameters for bioavailability by 55% (Cmax ) and 28% (AUCinf ). Rabeprazole was well-tolerated.

Maintenance of efficacy and safety of rabeprazole in children with endoscopically proven GERD

OBJECTIVE

The aim of the present study was to evaluate 24-week maintenance of efficacy and safety of rabeprazole in children with endoscopically proven gastroesophageal reflux disease (GERD).

METHODS

Children ages 1 to 11 years who achieved endoscopic/histologic healing (defined as grade 0 of the Hetzel-Dent Classification scale and/or grade 0 of the Histological Features of Reflux Esophagitis scale) in a 12-week treatment phase were continued on the same dose for an additional 24 weeks during the maintenance phase. The dose was determined by weight: children weighing 6 to 14.9 kg (low-weight cohort) received 5 or 10 mg and children weighing ≥ 15 kg (high-weight cohort) received 10 or 20 mg.

RESULTS

Healing was maintained in 90% of children (100% [low-weight cohort]; 89% [10 mg, high-weight cohort]; 85% [20 mg, high-weight cohort]). The Total GERD Symptom and Severity score continued to improve slightly in all of the children across all dose groups (P = 0.026) during the maintenance phase, except the 10-mg dose group (low-weight cohort), which experienced a slight worsening of 3.6 points. Overall, 71% children felt better on the GERD Symptom Relief score (P < 0.001); 95% of investigators and 92% of parent/caregivers rated "Good to Excellent" on the Global Treatment Satisfaction scale and Clinical Global Impressions Improvement scale, respectively. Overall incidence of treatment-emergent adverse events was 63%; upper respiratory tract infections (13%) and vomiting (11%) were the most commonly reported (>10%).

CONCLUSIONS

Rabeprazole was effective in maintaining endoscopic/histologic healing during a 24-week maintenance period in children with endoscopically proven GERD. The clinical effect and safety profile were largely similar across dose groups.

Safety and efficacy of delayed release rabeprazole in 1- to 11-month-old infants with symptomatic GERD

AIM

: The efficacy and safety of rabeprazole, a proton pump inhibitor, were studied in infants with gastroesophageal reflux disease (GERD).

METHODS

Infants ages 1 to 11 months, with symptomatic GERD resistant to conservative therapy and/or previous exposure to acid-suppressive medications, were screened. After scoring >16 on a GERD symptom score (Infant Gastroesophageal Reflux Questionnaire-Revised [I-GERQ]), 344 infants were enrolled in a 1- to 3-week open-label (OL) phase and received rabeprazole 10 mg/day. Following caregiver-rated clinical improvement during the OL phase, patients were randomized to placebo, rabeprazole 5 mg, or rabeprazole 10 mg in the ensuing 5-week double-blind (DB) withdrawal phase. Primary endpoints evaluated from DB baseline to the end of the DB withdrawal phase included frequency of regurgitation, weight-for-age z score, and daily and weekly GERD symptom scores.

RESULTS

Overall, 231 (86%) of the 268 randomized infants (placebo: 90; rabeprazole 5 mg: 90; rabeprazole 10 mg: 88) completed the study. Efficacy endpoints were similarly improved during the OL phase in all of the groups, and continued improving during the DB withdrawal phase with no difference between the placebo and combined rabeprazole groups. Mean decrease in frequency of regurgitation (-0.79 vs -1.20 times per day; P = 0.168), in I-GERQ-Revised scores (-3.6 [-25%] vs -3.9 points [-27%]; P = 0.960), in I-GERQ-Daily Diary scores (-1.87 [-19%] vs -1.85 [-19%]; P = 0.968), and increase in weight-for-age z scores (mean [standard deviation]: 0.11 [0.329] vs 0.14 [0.295]; P = 0.440) indicated equal improvement. Equal percentages (47%) reported adverse events in placebo and combined rabeprazole groups, with no new safety signals emerging.

CONCLUSIONS

In those infants with GERD who improved with rabeprazole during the OL phase, improvements in symptoms and weight were similar in those who continued rabeprazole and those withdrawn to placebo during a 5-week DB phase.

Efficacy and safety of rabeprazole in children (1-11 years) with gastroesophageal reflux disease

OBJECTIVE

Evaluate the efficacy and safety of rabeprazole in children, 1 to 11 years old, with endoscopically/histologically proven gastroesophageal reflux disease (GERD).

METHODS

Children were randomized to 0.5- or 1.0-mg/kg rabeprazole granule formulation for 12 weeks. The dose was further determined by weight: children 6 to 14.9 kg (low-weight cohort) received 5 or 10 mg and children ≥15 kg (high-weight cohort) received 10 or 20 mg. The primary endpoint was endoscopic/histologic healing at week 12 (defined as grade 0 on the Hetzel-Dent classification scale and/or grade 0 on the Histological Features of Reflux Esophagitis scale).

RESULTS

Overall, 81% (87/108) achieved endoscopic/histologic healing at week 12 with higher healing in the low-weight cohort (82% [5-mg dose], 94% [10-mg dose]) compared with high-weight cohort (76% [10-mg dose], 78% [20-mg dose]). There was a significant (P < 0.001) decrease in the mean Total GERD Symptoms and Severity score from 19.7 points (baseline) to 8.6 points (week 12), with 26% fewer children reporting GERD symptoms at week 12. The average frequency of symptoms per child decreased from 7.7 (week 1) to 4.7 (week 12). The GERD Symptom Relief score showed that 71% of children felt better, 81% were rated "good to excellent" on the Global Treatment Satisfaction scale by the investigator; 77% were rated "good to excellent" on the Clinical Global Impressions-Improvement scale by the parent/caregiver. The most common (>10%) treatment-emergent adverse events included cough and vomiting (14% each), abdominal pain (12%), and diarrhea (11%).

CONCLUSIONS

Rabeprazole was effective and safe in 1- to 11-year-old children with GERD.

Proton pump inhibitors in pediatrics : mechanism of action, pharmacokinetics, pharmacogenetics, and pharmacodynamics

Proton pump inhibitors (PPIs) have become some of the most frequently prescribed medications for treatment of adults and children. Their effectiveness for treatment of peptic conditions in the pediatric population, including gastric ulcers, gastroesophageal reflux disease (GERD), and Helicobacter pylori infections has been established for children older than 1 year. Studies of the preverbal population of neonates and infants have identified doses that inhibit acid production, but the effectiveness of PPIs in the treatment of GERD has not been established except for the recent approval of esomeprazole treatment of erosive esophagitis in infants. Reasons that have been proposed for this are complex, ranging from GERD not occurring in this population to a lack of histologic identification of esophagitis related to GERD to questions about the validity of symptom scoring systems to identify esophagitis when it occurs in infants. The effectiveness of PPIs relates to their structures, which must undergo acidic activation within the parietal cell to allow the PPI to be ionized and form covalent disulfide bonds with cysteines of the H(+)-K(+)-adenosine triphosphatase (H(+)-K(+)-ATPase). Once the PPI binds to the proton pump, the pump is inactivated. Some PPIs, such as omeprazole and rabeprazole bind to cysteines that are exposed, and their binding can be reversed. After irreversible chemical inhibition of the proton pump, such as occurs with pantoprazole, the recovery of the protein of the pump has a half-life of around 50 h. Cytochrome P450 (CYP) 2C19 and to a lesser degree CYP3A4 clear the PPIs metabolically. These enzymes are immature at birth and reach adult levels of activity by 5-6 months after birth. This parallels studies of the maturation of CYP2C19 to adult levels by roughly the same age after birth. Specific single nucleotide polymorphisms of CYP2C19 reduce clearance proportionally and increase exposure and prolong proton pump inhibition. Prolonged treatment of pediatric patients with PPIs has not caused cancer or significant abnormalities.