A Proton Pump Inhibitor in the Reformulation Setting: Bioequivalence and Potential Implications for Long-Term Safety

Evaluation of Obesity-Related Physiological Changes on Pantoprazole Clearance in Children Using a Population Pharmacokinetic Approach

Pediatric obesity is a growing health concern, affecting millions of children worldwide. While pharmacokinetic (PK) changes in numerous commonly prescribed medications have been linked to obesity, the physiological mechanisms driving these alterations and their implications for drug dosing remain poorly understood. The objective of this study was to evaluate previously reported observations of reduced pantoprazole clearance (CL) in children with obesity, investigate obesity-related characteristics in liver physiology as explanatory causes for these observations, and evaluate the clinical relevance of obesity on drug dosing. A prospective, comparative PK study, enrolling participants 6-21 years of age, with and without obesity, was conducted to evaluate the association between obesity-related characteristics and pantoprazole CL. A nonlinear mixed-effects modeling approach was used to identify sources of interindividual variability in pantoprazole PK. Monte Carlo simulations were performed to assess pantoprazole exposure in children and evaluate the association between obesity and pantoprazole exposure. The study population consisted of 39 pediatric participants: 31% without obesity and 69% with obesity. A two-compartment PK model with covariate effects of total body weight (TBW), CYP2C19 metabolizer phenotype, and obesity status adequately described the PK data. After accounting for differences due to TBW and CYP2C19 metabolizer phenotype, obesity was associated with an estimated 18% reduction in pantoprazole CL (comparable to the reduction estimated for a CYP2C19 loss of function allele). Further research is warranted to evaluate the physiological mechanisms associated with reduced drug CL in children with increased body size and the implications for drug dosing.

Population pharmacokinetics of omeprazole in obese and normal-weight adults

BACKGROUND

Obesity is related to many pathophysiological changes that may result in altered drug disposition. Omeprazole is the most common option utilized for acid-related disorders treatment; however, the pharmacokinetic (PK) and dosing recommendations for the obese patient population are lacking.

METHODS

Data from 40 healthy subjects with normal weights and data from 61 obese subjects were included. The subjects all received a single dose of 20 mg of omeprazole. Nonlinear mixed effects modeling were performed to characterize the effect of obesity on omeprazole PK.

RESULTS

A one-compartment model with twelve transit absorption compartments and linear elimination described the data best. A lower clearance was observed in the obese patient population than in the normal-weight subjects, which was opposite to the well-known allometric effect of body weight on drug clearance. Moreover, the CYP2C19 genotype was identified as a significant covariate for clearance.

CONCLUSION

Given the potential adverse events related to high exposure to proton pump inhibitors over time, obese patients may require a lower dose of omeprazole for long-term treatment. Further studies in obese individuals into other drugs metabolized by CYP2C19 are warranted, especially those with a narrow therapeutic window.

CLINICAL TRIAL REGISTRATION

www.chictr.org.cn identifier is ChiCTR2100046578; www.chinadrugtrials.org.cn identifier is CTR20190175.

Helicobacter pylori Related Diseases and Osteoporotic Fractures (Narrative Review)

Osteoporosis (OP) and osteoporotic fractures (OFs) are common multifactorial and heterogenic disorders of increasing incidence. Helicobacter pylori (H.p.) colonizes the stomach approximately in half of the world's population, causes gastroduodenal diseases and is prevalent in numerous extra-digestive diseases known to be associated with OP/OF. The studies regarding relationship between H.p. infection (HPI) and OP/OFs are inconsistent. The current review summarizes the relevant literature on the potential role of HPI in OP, falls and OFs and highlights the reasons for controversies in the publications. In the first section, after a brief overview of HPI biological features, we analyze the studies evaluating the association of HPI and bone status. The second part includes data on the prevalence of OP/OFs in HPI-induced gastroduodenal diseases (peptic ulcer, chronic/atrophic gastritis and cancer) and the effects of acid-suppressive drugs. In the next section, we discuss the possible contribution of HPI-associated extra-digestive diseases and medications to OP/OF, focusing on conditions affecting both bone homeostasis and predisposing to falls. In the last section, we describe clinical implications of accumulated data on HPI as a co-factor of OP/OF and present a feasible five-step algorithm for OP/OF risk assessment and management in regard to HPI, emphasizing the importance of an integrative (but differentiated) holistic approach. Increased awareness about the consequences of HPI linked to OP/OF can aid early detection and management. Further research on the HPI-OP/OF relationship is needed to close current knowledge gaps and improve clinical management of both OP/OF and HPI-related disorders.

Lean body weight dosing avoids excessive systemic exposure to proton pump inhibitors for children with obesity

BACKGROUND

Children with obesity are more likely to suffer gastroesophageal reflux disease, requiring acid-suppression therapy with proton pump inhibitors (PPIs) and no guidelines regarding dosing.

OBJECTIVE

To prospectively evaluate lean-body-weight-based (LBW) dosing of the PPI pantoprazole for children with and without obesity.

METHODS

Methods: Sixty-two children (6-17 years) received a one-time oral dose of liquid pantoprazole (1.2 mg kg^-1 LBW). Plasma pantoprazole concentrations were measured at 10 time points over 8 h and pharmacokinetic (PK) profiles generated using non-compartmental techniques, in order to compare PK parameters of interest between children with and without obesity, while accounting for CYP2C19 genotype.

RESULTS

Adjusted for milligram-per-kilogram total body weight (TBW) pantoprazole received, apparent drug clearance (CL/F) was reduced 50% in children with vs. without obesity (p=0.03). LBW-based dosing compensated for this reduction in CL/F (p = 0.15).

CONCLUSION

To achieve comparable systemic PPI exposures for children with and without obesity, we recommend using LBW, rather than TBW-based dosing for pantoprazole.

A Population-Based Pharmacokinetic Model Approach to Pantoprazole Dosing for Obese Children and Adolescents

BACKGROUND AND AIMS

Pharmacokinetic data for proton pump inhibitors (PPIs), acid-suppression drugs commonly prescribed to children, are lacking for obese children who are at greatest risk for acid-related disease. In a recent multi-center investigation, we demonstrated decreased, total body weight adjusted, apparent clearance (CL/F) of the PPI pantoprazole for obese children compared with their non-obese peers. Subsequently, we developed a population-based pharmacokinetic (PopPK) model to characterize pantoprazole disposition and evaluated appropriate pantoprazole dosing strategies for obese pediatric patients, using simulation.

METHODS

Pharmacokinetic data from the only prospective study of PPIs in obese children (aged 6-17 years; n = 40) included 273 pantoprazole and 256 pantoprazole-sulfone plasma concentrations, after single oral-dose administration, and were used for pantoprazole model development and covariate analysis (NONMEM®). Model evaluation was performed via bootstrapping and predictive checks, and the final model was applied to simulate systemic pantoprazole exposures for common dosing scenarios.

RESULTS

A two-compartment PopPK model, which included CYP2C19 genotype and total body weight, provided the best fit. Resultant, typical, weight-normalized pantoprazole parameter estimates were different than previously reported for children or adults, with significantly reduced pantoprazole CL/F for obese children. Of the dosing scenarios evaluated, the weight-tiered approach, approved by the US Food and Drug Administration, achieved pantoprazole exposures [area under the curve (AUC0-∞)] within ranges previously reported as therapeutic, without over- or under-prediction for obese children.

CONCLUSIONS

Our data argue against empiric dose escalation of PPIs for obese children and support current FDA-approved pediatric weight-tiered dosing for pantoprazole; however, 3- to 5-fold inter-individual variability in pantoprazole AUC0-∞ remained using this dosing approach.