The use of proton pump inhibitors in children: a comprehensive review

Acid suppression does not change respiratory symptoms in children with asthma and gastro-oesophageal reflux disease

BACKGROUND

Epidemiological studies have shown an association between gastro-oesophageal reflux disease (GORD) and asthma, and oesophageal acid perfusion may cause bronchial constriction. However, no causative relation has been proven.

AIM

To assess whether acid suppression would lead to reduced asthma symptoms in children with concomitant asthma and GORD.

METHODS

Thirty eight children (mean age 10.8 years, range 7.2-16.8; 29 males) with asthma and a reflux index > or =5.0 assessed by 24 hour oesophageal pH monitoring were randomised to 12 weeks of treatment with omeprazole 20 mg daily or placebo. The groups were similar in age, gender, mean reflux index, and asthma severity. Primary endpoints were asthma symptoms (daytime wheeze, symptoms at night, in the morning, and during exercise) and quality of life (PAQLQ). Secondary endpoints were changes in lung function and the use of short acting bronchodilators. At the end of the study a repeated pH study was performed to confirm the efficacy of acid suppression.

RESULTS

The change in total symptom score did not differ significantly between the omeprazole and the placebo group, and decreased by 1.28 (95% CI -0.1 to 2.65) and 1.28 (95% CI -0.72 to 3.27) respectively. The PAQLQ score increased by 0.62 (95% CI 0.29 to 0.95) in the omeprazole group compared to 0.50 (95% CI 0.29 to 0.70) in the placebo group. Change in lung function and use of short acting bronchodilators were similar in the groups. The acid suppression was adequate (reflux index <5.0) under omeprazole treatment.

CONCLUSION

Omeprazole treatment did not improve asthma symptoms or lung function in children with asthma and GORD.

Pharmacokinetics of proton pump inhibitors in children

The use of proton pump inhibitors (PPIs) has become widespread in children and infants for the management of paediatric acid-related disease. Pharmacokinetic profiles of only omeprazole and lansoprazole have been well characterised in children over 2 years of age with acid-related diseases. Few data have been recently published regarding the pharmacokinetics of pantoprazole in children, and none are available for rabeprazole or esomeprazole. The metabolism of PPI enantiomers has never been studied in the paediatric population. A one-compartment model best describes the pharmacokinetic behaviour of omeprazole, lansoprazole and pantoprazole in children, with important interindividual variability for each pharmacokinetic parameter. Like adults, PPIs are rapidly absorbed in children following oral administration; the mean time to reach maximum plasma concentration varies from 1 to 3 hours. Since these agents are acid labile, their oral formulations consist of capsules containing enteric-coated granules. No liquid formulation is available for any of the PPIs. Thus, for those patients unable to swallow capsules, extemporaneous liquid preparations for omeprazole and lansoprazole have been reported; however, neither the absolute nor the relative bioavailabilities of these oral formulations have been studied in children. Intravenous formulations are available for omeprazole (in Europe), lansoprazole and pantoprazole. PPIs are rapidly metabolised in children, with short elimination half-lives of around 1 hour, similar to that reported for adults. All PPIs are extensively metabolised by the liver, primarily by cytochrome P450 (CYP) isoforms CYP2C19 and CYP3A4, to inactive metabolites, with little unchanged drug excreted in the urine. Similar to that seen in adults, the absolute bioavailability of omeprazole increases with repeated dosing in children; this phenomenon is thought to be due to a combination of decreased first-pass elimination and reduced systemic clearance. The apparent clearance (CL/F) of omeprazole, lansoprazole and pantoprazole appears to be faster for children than for adults. A higher metabolic capacity in children as well as differences in the extent of PPI bioavailability are most likely responsible for this finding. This may partly account for the need in children for variable and sometimes considerably greater doses of PPIs, on a per kilogram basis, than for adults to achieve similar plasma concentrations. Furthermore, no studies have been able to demonstrate a statistically significant correlation between age and pharmacokinetic parameters among children. Despite the small number of very young infants studied, there is some evidence for reduced PPI metabolism in newborns. The limited paediatric data regarding the impact of CYP2C19 genetic polymorphism on PPI metabolism are similar to those reported for adults, with poor metabolisers having 6- to 10-fold higher area under the concentration-time curve values compared with extensive metabolisers. Finally, because a pharmacokinetic/pharmacodynamic relationship exists for PPIs, the significant interindividual variability in their disposition may partly explain the wide range of therapeutic doses used in children. Further studies are needed to better define the pharmacokinetics of PPIs in children <2 years of age.

Asthma and gastroesophageal reflux disease in children: exploring the relationship

Asthma is a well-recognized disease and one of the most common illnesses in childhood. More recently, gastroesophageal reflux disease has increasingly been appreciated as a common daily occurrence in children and adolescents. These two diagnoses often present in tandem, with their coexistence being more frequent than would be expected for a chance occurrence. The mainstay of asthma management is the regulation and control of chronic airway hyperreactivity and inflammation. Children who do not respond to standard asthma regimens should be evaluated for other sources of their pulmonary symptoms, most notably gastroesophageal reflux. Baseline assessment of pulmonary function tests followed by an empiric trial of proton pump inhibitor therapy, using double the standard doses commonly used in acid-related disorders and administered for 3 months, is a cost-effective, noninvasive diagnostic strategy. Children who fail to exhibit pulmonary symptom improvement should be evaluated for both medication compliance and proper administration. Twenty-four-hour esophageal pH monitoring with concurrent dairy recordings of their symptoms is recommended to ascertain adequacy of acid suppression and confirm the diagnosis in those who continue to have symptoms. Children with acid-related causes of their pulmonary symptoms often require long-term treatment. Studies have confirmed the efficacy, safety, and tolerability of proton pump inhibitors in the treatment of children and adolescents. Surgery should be reserved for those with severe disease and those who are unable to comply with pharmacologic treatment.

Inhibidores de la bomba de protones en pediatría

In last years the use in the pediatric area of proton pump inhibitors (omeprazole, lansoprazole, pantoprazole, rabeprazole and esomeprazole) is more often, nevertheless the clinical trials carried out are poor. The aim of this work is to analyse the bibliography published about this kind of drugs in children and to make a revision of its use in the last seven years. More studies with omeprazole and lansoprazole have been developed, to be exact omeprazole and lansoprazole is present in 122 bibliographic appointments and 34 for lansoprazole, which include studies that demonstrate a good tolerance and efficacy. The remaining proton pump inhibitors count with very few studies. The main therapeutic indications were the eradication of Helicobacter pylori, gastroesophageal reflux disease and esophagitis. The number of patients included in the reviewed studies is quite heterogeneous, from 8 to 122 and the age range between 8 days and 17 years. On the other hand, it could be highlighted the non-existence of formulations adapted to the pediatric population and the difficulty of administration specially in the youngest patients. As in many other drugs, it would be necessary to carry out clinical trials in order to determinate the pharmacologic parameters at difference ages, which will allow a safe and effective administration, and its authorization by all Health Authorities.

Identification of a hemin utilization protein of Moraxella catarrhalis (HumA)

Moraxella catarrhalis is a major cause of acute otitis media in young children and has also been implicated as an important cause of exacerbations in adults with underlying pulmonary disease. Due to the considerable level of antibiotic resistance and the high degree of carriage rates in young children, it is likely that the incidence of M. catarrhalis infections will continue to rise. M. catarrhalis is a strict human respiratory pathogen, and this bacterium uses both transferrin and lactoferrin receptors to fulfill the essential iron requirement for survival in vivo. However, these are the only described iron acquisition systems for this organism. In this report we have demonstrated that M. catarrhalis can also utilize hemin as a sole source of iron for growth. In addition, we have identified and characterized an outer membrane protein with homology (26 to 28% similarity) to other known hemin binding and uptake proteins in related gram-negative organisms (i.e., Bordetella and Yersinia spp.). This newly described M. catarrhalis protein, termed HumA, is capable of directly binding to hemin coupled to a solid-phase matrix. M. catarrhalis HumA expressed on the surface of an Escherichia coli hemA-deficient strain (K-12 EB53) is fully capable of complementing the defect and thus restoring the ability of this strain to grow in the presence of hemin. When M. catarrhalis is grown in the presence of hemin, HumA expression is clearly increased as shown by Western blotting with polyclonal antiserum developed against a HumA peptide. In addition, growth analyses revealed that a HumA-deficient mutant of M. catarrhalis (7169::humA) is restricted for growth in the presence of hemin as the sole iron source compared to the wild-type strain. We conclude that HumA is an essential component of a hemin uptake and utilization system previously undescribed for M. catarrhalis, thus providing another mechanism of iron acquisition that may facilitate persistent colonization of the mucosal surface.

Gastroesophageal reflux disease: could intervention in childhood reduce the risk of later complications?

Gastroesophageal reflux (GER) is a ubiquitous disorder in infants. Whereas infants typically outgrow regurgitation by 1 year of age, the prevalence of gastroesophageal reflux disease (GERD) symptoms in those aged 3 to >18 years ranges from 1.8% to 22%. The pathophysiology of GERD in children is similar to that in adults. However, children may present with gastroesophageal and extraesophageal symptoms distinct from classic heartburn. In addition to a growing awareness of the high prevalence of the disorder, increasing evidence supports GERD being a lifelong condition in some individuals that begins in childhood. Although the diagnostic workup in children compared with adults may differ, studies suggest that the early detection and treatment of GERD in childhood may result in better adult disease outcomes, improved quality of life, and decreased overall healthcare burden. Studies of proton pump inhibitor therapy in children confirm high rates of mucosal healing and GER symptom resolution, even in children whose symptoms did not respond to H2-receptor therapy or fundoplication procedures. Omeprazole, lansoprazole, and esomeprazole are formulated as capsules containing enteric-coated granules that can be sprinkled onto applesauce or other soft foods. Lansoprazole is also formulated as strawberry-flavored granules for suspension. These as well as other alternative dosing formulations expand the ability to administer these agents to children. Moreover, long-term studies in adults and in children demonstrate that these agents are safe and well tolerated, even at the higher milligram per kilogram doses that are often required in pediatric patients because of their greater hepatic metabolic capacity.

A novel option for dosing of proton pump inhibitors: dispersion of lansoprazole orally disintegrating tablet in water via oral syringe

BACKGROUND

A new formulation of lansoprazole, the lansoprazole orally disintegrating tablet, rapidly disintegrates in water eliminating the need for swallowing whole pills.

AIM

To assess the effect that dispersing the lansoprazole orally disintegrating tablet in water would have on lansoprazole pharmacokinetics.

METHODS

Forty healthy adult men and women (18-43 years) received two single 15 mg lansoprazole orally disintegrating tablet doses separated by 3 days (one administered directly onto the tongue without water and one dispersed in water and administered orally via syringe) in a randomized, crossover fashion. Serial plasma samples were determined from 0 to 12 h for each dose. Ratios of central values for peak plasma exposure (C(max)) and mean overall extent of exposure (area under the plasma concentration) were used to compare the bioavailability.

RESULTS

The two dosing regimens were bioequivalent, with the point estimate for area under the plasma concentration equalling 1.080 (confidence interval 1.012-1.152) and the point estimate for C(max) equalling 1.082 (confidence interval 0.961-1.218).

CONCLUSIONS

Dispersing the 15 mg lansoprazole orally disintegrating tablet in water and administering the dose orally via syringe is bioequivalent to the 15 mg intact lansoprazole orally disintegrating tablet with respect to lansoprazole area under the plasma concentration and C(max). This dosing route provides an additional, convenient dosing option for lansoprazole.

Longevity of balloon-stabilized skin-level gastrostomy device

OBJECTIVE

The gastrostomy button is increasingly used in patients requiring long-term enteral feeding. No data are available addressing the longevity of balloon-type gastrostomy buttons. The aim of this study was to evaluate the longevity of balloon-type gastrostomy buttons in children and the cause of the button removal.

PATIENTS AND METHODS

During a period of 2.5 years, 165 gastrostomy (Mic-Key, Medical Innovations Corporation, Draper, Utah, U.S.A.) buttons were inserted in 84 children. In all patients, the button replaced a standard tube gastrostomy. The first button was usually inserted under general anesthesia at least 2 months after the insertion of a surgical gastrostomy tube. Additional replacement was performed without sedation.

RESULTS

Mean longevity of balloon-type gastrostomy buttons was 5 months (range, 14 days-14 months). Causes of button removal were: inner balloon rupture (n = 101, 61%); leak around button or deflation of the balloon (n = 23, 14%); accidental removal (n = 20, 12%); device damage (n = 5), and obstruction (n = 3). When considering the subgroup with inner balloon rupture, the longevity of the button was 6 months (range, 1-13 months). No correlation was found between duration of gastrostomy button and underlying disease, age of the patient, or the use of antisecretory drugs.

CONCLUSION

Although the Mic-Key button has the advantage of an easy insertion, its major limitation is the high frequency of inner balloon rupture, which was the primary main reason for removal.