Dose-response relationship of lansoprazole to gastric acid antisecretory effects

Dasatinib anhydrate containing oral formulation improves variability and bioavailability in humans

Dasatinib monohydrate indicated for the treatment of chronic myeloid leukemia displays pH-dependent solubility. The aim of reported development program of novel dasatinib anhydrate containing formulation was to demonstrate improved absorption and lower pharmacokinetic variability compared to dasatinib monohydrate. In a bioavailability study comparing formulations containing 110.6 mg and 140 mg of dasatinib as anhydrate and monohydrate, respectively, both Cmax and AUC of dasatinib were within standard 80.00-125.00% range, while the intra- and inter-subject variability for AUC0-inf after the test product was approximately 3-fold and 1.5-fold less than after the reference, respectively.In a drug-drug interaction study, omeprazole 40 mg reduced the mean AUC0-inf of dasatinib by 19%, when the test was ingested 2 h before the 5th omeprazole dose. This decrease of exposure is clinically irrelevant and substantially less than after the reference. Co-prescription analysis supports the importance of pH-dependent solubility of dasatinib, as >21% of patients were treated concomitantly with a PPI and dasatinib despite warnings against this co-medication in the SmPC.The novel dasatinib anhydrate containing formulation demonstrated improved absorption and less pharmacokinetic variability compared to dasatinib monohydrate product, which may translate into improved clinical outcomes, although this needs to be proven by an appropriate trial.

Evaluation of Potential Food Effects and Drug Interactions With Lansoprazole in Healthy Adult Volunteers Receiving Futibatinib

Futibatinib, an oral, irreversible fibroblast growth factor receptor (FGFR) 1-4 inhibitor, is being evaluated for FGFR-aberrant tumors. Two open-label phase 1 studies evaluated the effects of high-fat, high-calorie food and concomitant proton pump inhibitors (PPIs; lansoprazole) on single-dose futibatinib (20 mg) pharmacokinetics and safety in healthy adults. In the food effect study (N  =  17), subjects received futibatinib under fed and fasted conditions, separated by a 7-day washout. In the PPI study (N  =  20), subjects received futibatinib alone, underwent a 2-day washout, and then received lansoprazole 60 mg once daily for 5 days, with futibatinib also administered on day 5. Under fed versus fasted conditions, futibatinib bioavailability was 11.2% lower (area under the plasma concentration-time curve from time 0 to infinity geometric mean ratio 88.8%; 90% confidence interval, 79.8%-98.9%), and median time to maximum plasma concentration was significantly delayed (4.0 vs 1.5 hours; P < .0001). There were no significant differences in futibatinib exposure between futibatinib plus lansoprazole and futibatinib alone. No serious adverse events occurred in either study. These findings suggest that food and PPIs are unlikely to have clinically meaningful impacts on futibatinib bioavailability. Thus, futibatinib may be used with or without food and concomitantly with acid-reducing agents.

A Review of Nutrients and Compounds, Which Promote or Inhibit Intestinal Iron Absorption: Making a Platform for Dietary Measures That Can Reduce Iron Uptake in Patients with Genetic Haemochromatosis

OBJECTIVE

To provide an overview of nutrients and compounds, which influence human intestinal iron absorption, thereby making a platform for elaboration of dietary recommendations that can reduce iron uptake in patients with genetic haemochromatosis.

DESIGN

Review. Setting. A literature search in PubMed and Google Scholar of papers dealing with iron absorption.

RESULTS

The most important promoters of iron absorption in foods are ascorbic acid, lactic acid (produced by fermentation), meat factors in animal meat, the presence of heme iron, and alcohol which stimulate iron uptake by inhibition of hepcidin expression. The most important inhibitors of iron uptake are phytic acid/phytates, polyphenols/tannins, proteins from soya beans, milk, eggs, and calcium. Oxalic acid/oxalate does not seem to influence iron uptake. Turmeric/curcumin may stimulate iron uptake through a decrease in hepcidin expression and inhibit uptake by complex formation with iron, but the net effect has not been clarified.

CONCLUSIONS

In haemochromatosis, iron absorption is enhanced due to a decreased expression of hepcidin. Dietary modifications that lower iron intake and decrease iron bioavailability may provide additional measures to reduce iron uptake from the foods. This could stimulate the patients' active cooperation in the treatment of their disorder and reduce the number of phlebotomies.

Interchangeable Use of Proton Pump Inhibitors Based on Relative Potency

Although proton pump inhibitors (PPIs) are widely used, their relative potency and ideal dosing regimens remain unclear. We analyzed data from randomized clinical trials that performed pH testing in patients receiving solid-dose PPI formulations (omeprazole, esomeprazole, lansoprazole, pantoprazole, rabeprazole) for a minimum of 5 days. We used omeprazole equivalency and the surrogate biomarker, percentage time pH > 4 over a 24-hour period (pH4time), to compare PPI effectiveness for different PPIs given once, twice, or 3 times daily. We found that increasing strength of once-daily PPIs (9-64 mg omeprazole equivalents) increased pH4time linearly from approximately 10.0 to 15.6 hours; higher doses produced no further increase in pH4time. Increasing the frequency to twice-daily PPI increased pH4time linearly, from approximately 15.8 to 21.0 hours. Three-times daily PPIs performed similarly to twice-daily PPIs. The costs of PPIs varied greatly, but the cost variation was not directly related to potency. We conclude that PPIs can be used interchangeably based on potency. Using twice-daily PPIs is more effective in increasing efficacy increasing once-daily PPI dosage. Omeprazole and lansoprazole (30 mg) and 20 mg of esomeprazole rabeprazole are functionally equivalent.

Antiresorptive effect of a cathepsin K inhibitor ONO-5334 and its relationship to BMD increase in a phase II trial for postmenopausal osteoporosis

Background

ONO-5334 is a cathepsin K inhibitor that induced bone mineral density (BMD) gain in a phase II study in postmenopausal osteoporosis patients. Even though the antiresorptive effect could only be monitored in the morning during the study, simulation can allow the antiresorptive effect to be assessed over 24 h, with assessment of the relationship to BMD gain.

Methods

Inhibition of the serum C-telopeptide of type I collagen (sCTX) level at doses of ONO-5334 of 100 mg once daily (QD), 300 mg QD, and 50 mg twice daily (BID) was simulated using plasma ONO-5334 pharmacokinetic (PK) data for repeated dose administration in a phase I study and corresponding sCTX inhibition from the PK-pharmacodynamic (PK/PD) relationship. sCTX was selected because it has a high signal-to-noise ratio compared to other telopeptides. A negative sigmoidal shape for the PK/PD relationship between plasma ONO-5334 and sCTX levels was obtained in our previous study.

Results

The simulated sCTX inhibition reached >99% of the maximal inhibitory effect (Emax) at 0.5 h in all treatment groups, and decreased to <80% Emax at 8 and 12 h at 50 mg BID and 100 mg QD, respectively. However, sCTX inhibition at 300 mg QD was maintained at ≥82% Emax over 24 h. The mean sCTX inhibition rates for 24 h at 100 mg QD, 300 mg QD and 50 mg BID were 63, 95 and 80% Emax, respectively. There was a positive linear relationship by treatment group between mean sCTX inhibition over 24 h and observed BMD gain in the phase II study.

Conclusion

The dose response for BMD with ONO-5334 at 100 and 300 mg QD and higher BMD gain at 50 mg BID vs. 100 mg QD can be explained by sCTX inhibition over 24 h. The simulation gave the antiresorptive effect of ONO-5334 over 24 h and allowed prediction of BMD gain due to ONO-5334.

Trial registration

The registration number in The European Union Clinical Trials Register is 2007–002417-39. The date of registration was August 31, 2007.

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-017-1625-y) contains supplementary material, which is available to authorized users.

A clinical study to examine the potential effect of lansoprazole on the pharmacokinetics of bosutinib when administered concomitantly to healthy subjects

BACKGROUND

Bosutinib is an orally bioavailable, dual Src and Abl tyrosine kinase inhibitor approved in the USA for the treatment of Philadelphia chromosome-positive chronic myeloid leukemia following development of resistance or intolerance to prior therapy. In vitro studies demonstrated that bosutinib displays pH-dependent aqueous solubility, suggesting that concomitant administration of agents that alter gastric pH could affect bosutinib absorption.

OBJECTIVES

The objectives of this study were to evaluate the effect of lansoprazole, a gastric proton pump inhibitor, on the pharmacokinetics and safety of bosutinib.

METHODS

This open-label, non-randomized, phase I study involved inpatients and outpatients at a single site. The study participants were healthy men or women of non-childbearing potential aged 18-50 years. Each subject received bosutinib 400 mg on Day 1, lansoprazole 60 mg on Day 14, and bosutinib 400 mg co-administered with lansoprazole 60 mg on Day 15 under fasting conditions. The main outcome measure was the effect of multiple doses of lansoprazole on the pharmacokinetic profile of a single oral dose of bosutinib.

RESULTS

A total of 24 healthy male subjects were enrolled. Co-administration with lansoprazole decreased the mean maximum plasma concentration (C(max)) of bosutinib from 70.2 to 42.9 ng/mL, and the total area under the plasma concentration-time curve (AUC) from 1,940 to 1,470 ng·h/mL. Log-transformed bosutinib pharmacokinetic parameters indicated significant between-treatment differences; the least squares geometric mean ratio for C(max) was 54 % (95 % CI 42-70) and for AUC was 74 % (95 % CI 60-90). Mean apparent total body clearance from plasma after oral administration increased from 237 to 330 L/h, and the median time to reach Cmax increased from 5 to 6 h, although this change may be related to decreased bosutinib absorption when combined with lansoprazole. When co-administered with lansoprazole, bosutinib maintained an acceptable safety profile, which was primarily characterized by diarrhea (33 %), headache (21 %), and nausea (13 %). One subject experienced serious adverse events of diverticulitis, gastritis, and duodenitis after co-administration; however, no participant withdrew because of toxicity.

CONCLUSIONS

This study demonstrated that bosutinib absorption may be reduced when co-administered with lansoprazole or other proton pump inhibitors. Caution should be used with such drug combinations, as subtherapeutic exposure of bosutinib may limit its clinical antitumor activity; short-acting antacids are recommended instead.

Effectiveness of three times daily lansoprazole/amoxicillin dual therapy for Helicobacter pylori infection in Korea

AIM

We compared three times daily dual therapy with standard triple therapy for effectiveness and safety in H. pylori infection.

METHODS

Two hundred and four H. pylori positive patients with peptic ulcer were randomly assigned to one of two regimens: (i) triple therapy with amoxicillin, clarithromycin and lansoprazole twice daily for 2 weeks or (ii) dual therapy with amoxicillin and lansoprazole three times daily for 2 weeks. The success of eradication was evaluated 4 to 5 weeks after completing treatment.

RESULTS

The eradication rate was 82.8% in the triple therapy group and 78.4% in the dual therapy group by per protocol analysis. This difference was not significant (P= 0.573). Adverse events were more frequent in the triple therapy group than in the dual therapy group (P= 0.002).

CONCLUSIONS

Because dual therapy had fewer side effects than triple therapy and a similar eradication rate, dual therapy may provide an acceptable alternative first line therapy for H. pylori eradication in Korea.

Effectiveness of three times daily lansoprazole/amoxicillin dual therapy for Helicobacter pylori infection in Korea

AIM

We compared three times daily dual therapy with standard triple therapy for effectiveness and safety in H. pylori infection.

METHODS

Two hundred and four H. pylori positive patients with peptic ulcer were randomly assigned to one of two regimens: (i) triple therapy with amoxicillin, clarithromycin and lansoprazole twice daily for 2 weeks or (ii) dual therapy with amoxicillin and lansoprazole three times daily for 2 weeks. The success of eradication was evaluated 4 to 5 weeks after completing treatment.

RESULTS

The eradication rate was 82.8% in the triple therapy group and 78.4% in the dual therapy group by per protocol analysis. This difference was not significant (P= 0.573). Adverse events were more frequent in the triple therapy group than in the dual therapy group (P= 0.002).

CONCLUSIONS

Because dual therapy had fewer side effects than triple therapy and a similar eradication rate, dual therapy may provide an acceptable alternative first line therapy for H. pylori eradication in Korea.

Systematic review: the use of proton pump inhibitors and increased susceptibility to enteric infection

The use of proton pump inhibitors (PPIs) is increasing worldwide. Suppression of gastric acid alters the susceptibility to enteric bacterial pathogens. AIM  This systematic review was undertaken to examine the relationship between PPI use and susceptibility to enteric infections by a specific pathogen based on published literature and to discuss the potential mechanisms of PPI enhanced pathogenesis of enteric infections. METHODS  PubMed, OVID Medline Databases were searched. Search terms included proton pump inhibitors and mechanisms of, actions of, gastric acid, enteric infections, diarrhoea, Clostridium difficile, Salmonella, Shigella and Campylobacter. RESULTS The use of PPIs increases gastric pH, encourages growth of the gut microflora, increases bacterial translocation and alters various immunomodulatory and anti-inflammatory effects. Enteric pathogens show variable gastric acid pH susceptibility and acid tolerance levels. By multiple mechanisms, PPIs appear to increase susceptibility to the following bacterial enteropathogens: Salmonella, Campylobacter jejuni, invasive strains of Escherichia coli, vegetative cells of Clostridium difficile, Vibrio cholerae and Listeria. We describe the available evidence for enhanced susceptibility to enteric infection caused by Salmonella, Campylobacter and C. difficile by PPI use, with adjusted relative risk ranges of 4.2-8.3 (two studies); 3.5-11.7 (four studies); and 1.2-5.0 (17 of 27 studies) for the three respective organisms. CONCLUSIONS Severe hypochlorhydria generated by PPI use leads to bacterial colonisation and increased susceptibility to enteric bacterial infection. The clinical implication of chronic PPI use among hospitalized patients placed on antibiotics and travellers departing for areas with high incidence of diarrhoea should be considered by their physicians.

PREDICTING EFFICACY OF PROTON PUMP INHIBITORS IN REGULATING GASTRIC ACID SECRETION

Developing drugs to treat gastric acid related illnesses such as ulcers and acid reflux disease is the leading focus of pharmaceutical companies. In fact, expenditure for treating these disorders is highest among all illnesses in the US. Over the last few decades, a class of drugs known as a proton pump inhibitors (PPIs) appeared on the market and are highly effective at abating gastric illnesses by raising stomach pH (reducing gastric acid levels). While much is known about the action of PPIs , there are still open questions regarding their efficacy, dosing and long-term effects. Here we extend a previous gastric acid secretion model developed by our group to incorporate a pharmacodynamic/pharmacokinetic model to study proton pump inhibitor (PPI) action. Model-relevant parameters for specific drugs such as omeprazole (OPZ) , lansoprazole (LPZ) and pantoprazole (PPZ) were used from published data, and we conducted simulations to study various aspects of PPI treatment. Clinical data suggests that duration of acid suppression is dependent on proton pump turnover rates and this is supported by our model. We found the order of efficacy of the different PPIs to be OPZ>PPZ>LPZ for clinically recommended dose values, and OPZ>PPZ=LPZ for equal doses. Our results indicate that a breakfast dose for once-daily dosing regimens and a breakfast-lunch dose for twice-daily dosing regimens is recommended. Simulation of other gastric disorders using our model provides atypical applications for the study of drug treatment on homeostatic systems and identification of potential side-effects.

Proton pump inhibitor-induced hypocalcemic seizure in a patient with hypoparathyroidism

OBJECTIVE

To report a case of proton pump inhibitor-induced hypocalcemic seizure in a patient with hypoparathyroidism.

METHODS

We describe the clinical history, physical examination findings, and laboratory values of the patient and briefly review the relevant literature.

RESULTS

A 48-year-old woman with a history of postsurgical hypoparathyroidism who was taking calcium carbonate, 1500 mg 3 times daily, and cholecalciferol, 1200 IU daily, presented with a generalized seizure in the setting of hypocalcemia 12 days after initiating therapy with the proton pump inhibitor lansoprazole. Physical examination revealed a positive Chvostek sign. Electrocardiogram was notable for a prolonged QT(c) interval of 576 milliseconds. Laboratory data were notable for the following values: total serum calcium, 5.3 mg/dL; ionized calcium, 2.51 mg/dL; and intact parathyroid hormone, 5.8 pg/mL. The patient's condition responded to therapy with intravenous calcium gluconate, oral calcium carbonate, and calcitriol. As an outpatient she remained asymptomatic off lansoprazole, treated with calcium carbonate and calcitriol.

CONCLUSIONS

Caution should be exercised in prescribing proton pump inhibitors to patients with a history of hypoparathyroidism treated with calcium carbonate supplementation because severe hypocalcemia is a potential adverse effect.

Relative potency of proton-pump inhibitors-comparison of effects on intragastric pH

AIM

Comparative potency of proton-pump inhibitors (PPIs) is an important clinical issue. Most available trials have compared the different PPIs at one or a few selected specific dosages, making it difficult to derive quantitative equivalence dosages. Here we derived PPI dose equivalents based on a comprehensive assessment of dose-dependent effects on intragastric pH.

METHODS

All available clinical studies reporting the effects of PPIs on mean 24-h intragastric pH were sought from electronic databases including Medline. Studies included were restricted to those targeting the Caucasian population, and healthy volunteers or gastroesophageal reflux disease (GERD) patients. The dose-effect relationships for mean 24-h intragastric pH and for percentage of time with pH > 4 in 24 h were analyzed for each PPI using pharmacodynamic modeling with NONMEM and a model integrating all available data.

RESULTS

Fifty-seven studies fulfilled the inclusion criteria. Based on the mean 24-h gastric pH, the relative potencies of the five PPIs compared to omeprazole were 0.23, 0.90, 1.00, 1.60, and 1.82 for pantoprazole, lansoprazole, omeprazole, esomeprazole, and rabeprazole, respectively. Compared with healthy volunteers, patients with GERD needed a 1.9-fold higher dose and Helicobacter pylori-positive individuals needed only about 20% of the dose to achieve a given increase in mean 24-h intragastric pH.

CONCLUSION

The present meta-analysis provides quantitative estimates on clinical potency of individual PPIs that may be helpful when switching between PPIs and for assessing the cost-effectiveness of specific PPIs. However, our estimates must be viewed with caution because only a limited dose range has been tested and not exactly the same study conditions were applied for the different substances.

Acid control with esomeprazole and lansoprazole: a comparative dose-response study

OBJECTIVE

To determine the level of acid control and the dose-response relationships achieved with esomeprazole and lansoprazole. These data are relevant in helping clinicians to decide on whether to increase a proton-pump inhibitor dose, or whether to switch to an alterative drug for increased acid control.

MATERIAL AND METHODS

In an open-label, single-centre, randomized, six-way crossover study, 40 healthy subjects received esomeprazole 20, 40 and 80 mg, and lansoprazole 15, 30 and 60 mg once daily for 5 days. The mean time with intragastric pH >4 and mean 24-h median intragastric pH on day 5 were analyzed using a mixed-model ANOVA. Post-hoc analyses were completed for 0-12-h (daytime) and 12-24-h (night-time) post-dose intervals.

RESULTS

Increasing the dose of esomeprazole from 20 mg to 40 mg resulted in significantly improved acid control over 0-12, 12-24 and 0-24 h post-dose (p<0.001), but no significant improvement in acid control for either period was seen when further increasing the dose to 80 mg. Increasing the dose of lansoprazole from 15 mg to 30 mg or from 30 mg to 60 mg significantly improved acid control over 0-12 and 0-24 h (p<0.01) but not over 12-24 h. With the exception of the esomeprazole 20 mg versus lansoprazole 30 mg comparisons, and the esomeprazole 20 mg versus lansoprazole 15 mg during 12-24 h post-dose comparison, esomeprazole provided significantly greater acid control than lansoprazole at each dose level over 0-12, 12-24 and 0-24 h (p<0.05). Mean 24-h median intragastric pH was higher following esomeprazole dosing compared with lansoprazole at each dose level.

CONCLUSIONS

For low-, standard- and double-dose comparisons, esomeprazole achieved greater elevation of gastric pH and better acid control in more subjects than lansoprazole. Use of esomeprazole may therefore reduce the need for dose adaptations or drug switching.

Effect of frequent dosing of an oral proton pump inhibitor on intragastric pH

BACKGROUND

Treatment with a continuous i.v. proton pump inhibitor is presumed to promote clot formation and stability by sustaining intragastric pH > or = 6.

AIM

We postulated that very frequent oral dosing of proton pump inhibitors should simulate i.v. infusion and achieve similar pH control.

METHODS

Twenty healthy volunteers were stratified by Helicobacter pylori status (10 positive; 10 negative) and had determination of CYP2C19 status. After an overnight fast, an intragastric pH probe was placed. Subjects received 120 mg of lansoprazole at 8 am and 30 mg every 3 h until 8 pm. Intragastric pH was measured over 24 h, and lansoprazole plasma concentrations were determined at five time points.

RESULTS

Intragastric pH was > or = 6 for 41% (95% CI: 30-53%) of the 15-h period from 8 am-11 pm and 46% (95% CI: 35-56%) of the 24-h period (8-8 am). The mean proportion of patients with pH > or = 6 was not significantly different in H. pylori-positive vs. negative patients. Only 25% of subjects sustained pH > or = 6 for at least 60% of the 15-h period, and 35% had a sustained pH > or = 6 for at least 60% of the 24-h period.

CONCLUSIONS

A dose of 120 mg of oral lansoprazole followed by standard 30 mg doses of lansoprazole every 3 h did not reliably sustain pH at the desired level of 6.

Rabeprazole 10 mg twice daily is superior to 20 mg once daily for night-time gastric acid suppression

BACKGROUND

Insufficient acid suppression is one of the main causes of proton pump inhibitor-refractory gastro-oesophageal reflux disease.

AIM

To achieve more potent and long-lasting acid suppression, different dosage regimens of rabeprazole were compared in relation to the CYP2C19 genotype status.

METHODS

In a cross-over study, 18 healthy Helicobacter pylori-negative males (six homozygous extensive metabolizers, six heterozygous extensive metabolizers and six poor metabolizers) were given rabeprazole 10 mg once daily, 20 mg once daily or 10 mg twice daily, or water only (baseline data), for 7 days each. On day 7 of each regimen, 24-h intragastric pH-metry was performed.

RESULTS

No significant differences were observed in median pH values and pH>4 holding time ratios between rabeprazole 10 mg once daily and 20 mg once daily. However, with rabeprazole 10 mg twice daily, these parameters were significantly higher than those with 20 mg once daily. The potency of acid suppression by rabeprazole was influenced by the CYP2C19 genotype status. The differences were somewhat significant but not large. The incidence of nocturnal acid breakthrough was lowest with rabeprazole 10 mg twice daily.

CONCLUSIONS

Rabeprazole 10 mg twice daily, not 20 mg once daily, should be administered to achieve more potent and long-lasting acid suppression.

Diagnostic and therapeutic options in the management of nonvariceal upper gastrointestinal bleeding

Upper gastrointestinal bleeding from peptic ulcers is common. Advances in prognostication, therapeutic endoscopy, and medical management have evolved rapidly. Patients most likely to rebleed after therapy can now be identified and monitored more closely, and patients with ulcers of low risk for rebleeding can be managed on an outpatient basis. High-risk patients include those with ulcers containing a visible vessel or who are actively bleeding. Endoscopic therapy is mandatory in high-risk patients and involves at least two hemostatic techniques. Second-look endoscopy and repeated hemostasis should be performed promptly in patients who rebleed. Adjunctive treatment includes intravenous proton pump inhibitor administered in high doses for the first 72 hours after endoscopic therapy. Further studies are needed to determine the optimal combination of hemostatic techniques to better target patients who are at risk for ulcer rebleeding.

Nutcracker oesophagus: a double-blind, placebo-controlled, cross-over study of the effects of lansoprazole

BACKGROUND

Nutcracker oesophagus is characterized by high-amplitude oesophageal contractions. Recent data have shown a high prevalence of gastro-oesophageal acid reflux in patients with nutcracker oesophagus and, in open-label trials, patients seemed to benefit from acid suppression. Therefore, it has been suggested that non-cardiac chest pain in patients with nutcracker oesophagus may be related to reflux rather than to the motor abnormality itself.

AIMS

To investigate the effect of intensive acid-suppressive treatment on chest pain in patients with nutcracker oesophagus.

METHODS

Nineteen patients with nutcracker oesophagus received lansoprazole or placebo in a double-blind, randomized, cross-over study.

RESULTS

Significant reductions in pain intensity (P < 0.006) and pain duration (P < 0.05) were registered during the study. The magnitude of symptom relief achieved with lansoprazole did not differ significantly from that achieved with placebo. The motility pattern did not change during the study.

CONCLUSIONS

This study does not prove that acid-suppressive therapy is effective for pain relief in nutcracker oesophagus. As the amelioration of pain was not accompanied by any change in the nutcracker oesophagus pattern, it is unlikely that the high-amplitude oesophageal contractions are the cause of pain. Thus, the possible role of acid in the pathophysiology of pain in nutcracker oesophagus needs further study.

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

Proton pump inhibitors (PPIs) belong to a group of chemically related compounds whose primary function is the inhibition of acid production in the final common metabolic pathway of gastric parietal cells. PPIs are highly selective and effective in their action and have few short- or long-term adverse effects. These pharmacologic features have made the development of PPIs the most significant advancement in the management of acid peptic related disorders in the last two decades. There are numerous published adult studies that describe the pharmacology, efficacy and safety of these anti-secretory agents; however, in the pediatric population, there are very few comparable studies, particularly multicenter studies with significant patient enrollment. In preparing this article, our aim was to perform a comprehensive review of the literature on the clinical pharmacology and use of PPIs in the pediatric population, and to briefly review some recent articles. Relevant literature was identified by performing MEDLINE/Pubmed searches from January 1990 to December 2001. Combinations of the following search terms were use to analyze these databases: proton pump inhibitor, children, pediatrics, gastroesophageal reflux disease (GERD), esophagitis, intestinal metaplasia, Helicobacter pylori, omeprazole, lansoprazole, pantoprazole, rabeprazole, esomeprazole, and safety. Abstracts from the 14th annual conference of the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition (NASPGHAN) 2001, and the Disease and Digestive Week 2001, were also included in the review. All pediatric studies reviewed were limited to either omeprazole or lansoprazole. The dosage range used for the management of GERD and related disorders with lansoprazole was 0.73-1.66 mg/kg/day (maximum 30 mg/day). The dosage range for GERD management using omeprazole was 0.3-3.5 mg/kg (maximum 80 mg/day). The dosage range for omeprazole used for H. pylori was 0.5-1.5 mg/kg/day, with a maximum dosage of 40 mg/day, and lansoprazole-containing regimens for H. pylori eradication used dosages ranging from 0.6-1.2 mg/kg/day, with a maximum dosage of 30 mg/day. Few severe adverse events were reported with the use of either drug. Eradication rates for H. pylori were 56-87% for lansoprazole-based triple therapy, and 75-94% for omeprazole-based eradication regimens. To date, there are no published controlled trials of sufficient power comparing the efficacy of the five commercially available PPIs in children, for a variety of acid peptic diseases. Studies suggest that PPIs are highly effective for the management of GERD and related disorders, and are a critically needed component of triple therapy to eradicate H. pylori. PPIs have a very good tolerability profile in adults and children, but long-term tolerability studies are needed, particularly in the pediatric population. Multicenter studies are critically needed to evaluate the second-generation PPIs, to compare PPI efficacy to each other, and to assess the importance of developmental and genetic pharmacology of these drugs in children with acid-peptic disease.

Effective intra-oesophageal acid suppression in patients with gastro-oesophageal reflux disease: lansoprazole vs. pantoprazole

BACKGROUND

: Effective intra-oesophageal acid suppression is an important therapeutic goal in complicated and atypical gastro-oesophageal reflux disease.

AIM

: To compare the efficacy of lansoprazole and pantoprazole in normalizing oesophageal acid exposure.

METHODS

: Fifty patients with complicated or atypical gastro-oesophageal reflux disease were randomly assigned to receive 30 mg lansoprazole (n = 26) or 40 mg pantoprazole (n = 24) once daily. Three to four weeks after the start of treatment, patients underwent 24-h oesophageal pH monitoring whilst on therapy. If the results were improved but still abnormal, the dosage was doubled and pH monitoring was repeated. If oesophageal acid exposure was not improved, the patient was shifted to the alternative drug regimen.

RESULTS

: Oesophageal acid exposure was normalized in all 26 patients treated with lansoprazole (in 35% of cases with a double daily dosage), whereas in six of the 24 (25%) patients treated with pantoprazole it was neither normalized nor lowered (P = 0.008). Accordingly, the mean percentage acid reflux time was significantly lower for the lansoprazole group (2.1) than for the pantoprazole group (5.8) (P = 0.032).

CONCLUSIONS

: Effective intra-oesophageal acid suppression can be accomplished more reliably with lansoprazole than with pantoprazole in patients with complicated and atypical gastro-oesophageal reflux disease.

Hiatal hernia is the key factor determining the lansoprazole dosage required for effective intra-oesophageal acid suppression

BACKGROUND

Effective intra-oesophageal acid suppression can be achieved with lansoprazole. The daily dosage could be influenced by the presence of hiatal hernia.

AIM

To assess the lansoprazole daily dosage required to normalize oesophageal acid exposure in patients with and without hiatal hernia.

METHODS

Fifty patients with complications or atypical manifestations of gastro-oesophageal reflux disease were given lansoprazole, 30 mg once daily. Three to four weeks after the start of treatment, patients underwent oesophageal pH monitoring while on therapy. If the results were still abnormal, the lansoprazole dosage was doubled and 24-h pH-metry was repeated 20-30 days thereafter.

RESULTS

A 30-mg daily dosage of lansoprazole normalized oesophageal acid exposure in 70% of cases, whilst a 60-mg daily dosage was necessary in the remainder: the two groups differed only in the presence of hiatal hernia (28% vs. 100%, respectively; P=0.000). Effective intra-oesophageal acid suppression was obtained in all 25 patients without hiatal hernia with the 30-mg daily dosage of lansoprazole.

CONCLUSIONS

Hiatal hernia is the key factor determining the lansoprazole dosage required for effective intra-oesophageal acid suppression in complicated and atypical gastro-oesophageal reflux disease. High efficacy of a 30-mg daily dosage of lansoprazole can be predicted in the absence of hiatal hernia.

Lansoprazole vs. omeprazole for gastro-oesophageal reflux disease: a pH-metric comparison

BACKGROUND

Lansoprazole and omeprazole are widely used proton pump inhibitors for the management of gastro-oesophageal reflux. Normalization of oesophageal acid exposure is an important goal in the management of complicated and atypical gastro-oesophageal reflux disease.

AIM

To compare the efficacy of lansoprazole and omeprazole in the abolition of abnormal reflux as assessed by oesophageal pH monitoring.

METHODS

Seventy patients with complicated or atypical gastro-oesophageal reflux disease were randomly assigned to receive 30 mg lansoprazole or 20 mg omeprazole once daily. Three to four weeks after the start of treatment, patients underwent oesophageal pH monitoring while on therapy. If the results were still abnormal, the proton pump inhibitor dosage was doubled and 24-h pH-metry was repeated after 20-30 days.

RESULTS

Thirty-six patients were randomized to receive lansoprazole and 34 patients to receive omeprazole. Ten of the 36 (29%) patients treated with 30 mg lansoprazole once daily and 23 of the 34 (68%) patients treated with 20 mg omeprazole once daily had persistently abnormal reflux at oesophageal pH monitoring (P < 0.001). In all such cases, repeat pH monitoring after doubling the proton pump inhibitor dosage gave normal results.

CONCLUSIONS

At the currently marketed dosages of lansoprazole and omeprazole, normalization of oesophageal acid exposure in patients is accomplished more easily with lansoprazole.

Does short-term treatment with proton pump inhibitors cause rebound aggravation of symptoms?

BACKGROUND

Rebound acid hypersecretion might occur after treatment with proton pump inhibitors. This study looks for a rebound aggravation of symptoms after short-term treatment with lansoprazole.

STUDY

Sixty-two patients (19 men and 43 women; mean age, 54 years; range, 32-77 years) with heartburn and regurgitation and normal upper endoscopy findings were studied in a randomized, double-blind, placebo-controlled trial with a crossover design. There were two 5-day treatment periods with lansoprazole 60 mg once daily or placebo in random order, separated by a 9-day washout period. Reflux, total, and antacid scores were calculated for each of the treatment periods. Higher scores during the placebo period in the group given lansoprazole first than in the group given placebo first indicated a rebound aggravation of symptoms.

RESULTS

The mean symptom scores during the placebo period in the groups given lansoprazole first and placebo first were as follows: reflux score, 21.5 and 17.6, respectively (not significant); total score, 11.2 and 10.3, respectively (not significant); and antacid score, 8.2 and 7.2, respectively (not significant).

CONCLUSIONS

There is no indication of a rebound aggravation of symptoms 12 to 14 days after a 5-day treatment with lansoprazole 60 mg once daily in patients with reflux symptoms.

Pharmacological and pharmacodynamic essentials of H(2)-receptor antagonists and proton pump inhibitors for the practising physician

The suppression of gastric acid secretion with anti-secretory agents has been the mainstay of medical treatment for patients with acid-related disorders. Although the majority of Helicobacter pylori -related peptic ulcers can be healed with antibiotics, ulcer healing and symptom control can be significantly improved when antibiotics are given with anti-secretory agents, especially with a proton pump inhibitor. There is a dynamic relationship between the suppression of intragastric acidity and the healing of peptic ulcer and erosive oesophagitis and control of acid-related symptoms. The suppression of gastric acid secretion achieved with H(2)-receptor antagonists has, however, proved to be suboptimal for effectively controlling acid-related disorders, especially for healing erosive oesophagitis and for the relief of reflux symptoms. H(2)-receptor antagonists are also not effective in inhibiting meal-stimulated acid secretion, which is required for managing patients with erosive oesophagitis. Furthermore, the rapid development of tolerance to H(2)-receptor antagonists and the rebound acid hypersecretion after the withdrawal of an H(2)-receptor antagonist further limit their clinical use. Although low-dose H(2)-receptor antagonists are currently available as over-the-counter medications for self-controlling acid-related symptoms, their pharmacology and pharmacodynamics have not been well studied, especially in the self-medicating population. Proton pump inhibitors have been proved to be very effective for suppressing intragastric acidity to all known stimuli, although variations exist in the rapidity of onset of action and the potency of acid inhibition after oral administration at the approved therapeutic doses, which may have important clinical implications for the treatment of gastro-oesophageal reflux disease and perhaps for eradicating H. pylori infection when a proton pump inhibitor is given with antibiotics. Once-daily dosing in the morning is more effective than dosing in the evening for all proton pump inhibitors with respect to the suppression of intragastric acidity and daytime gastric acid secretion in particular, which may result from a better bio-availability being achieved with the morning dose. When higher doses are needed, these drugs must be given twice daily to achieve the optimal suppression of 24 hour intragastric acidity. Preliminary results have shown that esomeprazole, the optical isomer of omeprazole, given at 40 mg, is significantly more effective than omeprazole 40 mg, lansoprazole 30 mg or pantoprazole 40 mg for suppressing gastric acid secretion. However, more studies in different patient populations are needed to compare esomeprazole with the existing proton pump inhibitors with regard to their efficacy, cost-effectiveness and long-term safety for the management of acid-related disorders.

Review article: should we kill or should we save Helicobacter pylori?

Results from epidemiological studies and therapeutic clinical trials have shown that Helicobacter pylori infection causes acute and chronic active gastritis and is the initiating factor for the majority of peptic ulcer disease. Eradication of the infection with antibiotics resolves gastritis and restores normal gastric physiology, accelerates healing of peptic ulcer disease, and virtually eliminates recurrence of duodenal ulcer disease. The infection also plays an important role in the initiation and/or progression of gastric atrophy and intestinal metaplasia, which may eventually lead to the development of distal gastric cancer. Furthermore, almost all patients with gastric MALT lymphoma are infected with H. pylori and cure of the infection leads to histological regression of the tumor and maintains the regression in over 80% of patients during long-term follow-up. Preliminary uncontrolled data from Japan show that eradication of the infection significantly reduced metachronous intestinal-type gastric cancer following initial endoscopic resection of early gastric cancer and might also prevent the progression of gastric adenoma to gastric dysplasia or gastric cancer. Although this overwhelming evidence has demonstrated that H. pylori infection is bad for humans, some have questioned the wisdom of eradicating the infection in all those infected. Their arguments are largely based on hypothesis and circumstantial evidence: 1) Less than 20% of all H. pylori infected persons will develop significant clinical consequences in their lifetime. 2) H. pylori strains are highly diverse at a genetic level and are of different virulence. 3) The antiquity of H. pylori infection in humans and their co-evolution suggests that H. pylori may be a commensal to humans. Eradication of H. pylori may remove some beneficial bacterial strains and may provoke esophageal disease or gastric cancer at the cardia. However, careful review of the literature confirms that H. pylori infection is a serious pathogen albeit in a minority of those infected. It remains for carefully designed prospective studies, rather than hypothesis to make changes in the current consensus position.

Pharmacodynamic modeling of lansoprazole using an indirect irreversible response model

A mechanism-based pharmacokinetic/pharmacodynamic model was used to assess lansoprazole effects on gastric pH. The irreversible inactivation of the H+/K+-ATPase enzyme by lansoprazole controls the secretion rate of H+ ions and gastric pH values. The basal circadian rhythm of gastric acid production was taken into account as well as the effects of food intake. A model was applied to multiple-dose data from a crossover study of four dosage regimens of lansoprazole in two groups of normal male subjects. Model parameters were estimated by nonlinear regression and were compared to historical values reported in the literature. The predicted mean gastric ion concentration was 23.2 mM (pH 1.6) with the peak time at 12.6 hours (8:30 p.m.), and the half-time for H+ removal from the stomach averaged 1.7 hours. The estimated half-life of gastric food removal was 0.8 hours. The rate constant for normal H+/K+-ATPase degradation was 0.045 h(-1). The pharmacodynamic parameter describing lansoprazole action on gastric acid secretion was the second-order enzyme inactivation constant, which averaged 0.16 microg(-1) x L x h(-1). The parameters obtained for both the baseline and drug treatment data were consistent with the literature and physiologically relevant with the exception of effective food volume, which was large presumably due to buffer effects. The model successfully incorporated the physiological regulation of gastric acid production, the effects of food on gastric acid, and the effects of multiple-dosing regimens of lansoprazole on gastric acid production to give reasonable profiles of gastric pH.

Nasogastric lansoprazole is effective in suppressing gastric acid secretion in critically ill patients

AIM

To evaluate the effect of nasogastric lansoprazole on acid suppression in critically ill patients.

METHODS

Patients were eligible for the study if they had a nasogastric tube in place and had not received acid-suppressive agents for 3 days prior to enrolment into the study. Patients with active gastrointestinal bleeding or a baseline gastric pH > 4.0 were excluded. Patients served as their own controls during a 24 h lead-in period. Lansoprazole 30 mg was administered once daily with water through a nasogastric tube for 2 days. Intragastric pH was measured by continuous 24 h pH-metry for 3 days.

RESULTS

Fifteen patients were enrolled into the study. The baseline median 24 h intragastric pH was 2.25 +/- 1.01, and increased to 6.70 +/- 0.82 (P= 0.001) after 2 days of lansoprazole. Mean percentage of time intragastric pH was > or = 4.0 was 25 +/- 13% at baseline, and increased to 84 +/- 14% (P=0. 001) after 2 days of lansoprazole.

CONCLUSIONS

Nasogastric lansoprazole 30 mg daily is effective in suppressing gastric acid secretion in critically ill patients.

Triple versus dual therapy for eradicating Helicobacter pylori and preventing ulcer recurrence: a randomized, double-blind, multicenter study of lansoprazole, clarithromycin, and/or amoxicillin in different dosing regimens

OBJECTIVE

The efficacy and safety of dual and triple therapies with a proton pump inhibitor and antibiotic(s) for therapy of Helicobacter pylori-associated duodenal ulcer disease have been compared using results from independent studies using different methods and regimens, making interpretation difficult. In a large, double-blind, multicenter study conducted in the United States, we compared a triple therapy regimen with four dual therapy and one monotherapy regimens in the eradication of H. pylori and the prevention of ulcer recurrence.

METHODS

Patients with active duodenal ulcer disease or history of duodenal ulcer disease within the past year and H. pylori infection were randomized to receive one of six 14-day treatment regimens: lansoprazole 30 mg, clarithromycin 500 mg, and amoxicillin 1 gm b.i.d.; lansoprazole 30 mg b.id. and either clarithromycin 500 mg b.i.d. or t.i.d.; lansoprazole 30 mg b.i.d. or t.i.d. with amoxicillin 1 gm t.i.d.; or lansoprazole 30 mg t.i.d. alone. No additional acid suppression therapy followed eradication therapy. Primary efficacy endpoints were eradication of H. pylori and ulcer recurrence.

RESULTS

Of 396 patients enrolled in the study, 352 met the entry criteria for duodenal ulcer status and H. pylori positivity. At 4-6 wk after the end of therapy, H. pylori was eradicated from 94% (44 of 47) of patients receiving lansoprazole, clarithromycin, and amoxicillin triple therapy, 77% (39 of 51) of those receiving lansoprazole t.i.d./amoxicillin t.i.d., 75% (36 of 48) of those receiving lansoprazole b.i.d./clarithromycin t.i.d., 57% (28 of 49) of those receiving lansoprazole b.i.d./clarithromycin b.i.d., 53% (26 of 49) of those receiving lansoprazole b.i.d./amoxicillin t.i.d., and 2% (1 of 53) of those receiving lansoprazole monotherapy (p < or = 0.05, triple therapy vs each dual therapy and each dual therapy vs monotherapy). Of those patients who were documented as free of ulcer at 4-6 wk after treatment, ulcers recurred within 6 months in 7% of patients receiving triple therapy, as compared with 13-23% of patients receiving dual therapy, and 69% of patients receiving lansoprazole monotherapy. Patients who were H. pylori negative at 4-6 wk after treatment were less likely to have an ulcer recurrence than were patients who were H. pylori positive (11% [10 of 95] vs 47% [20 of 43], respectively, across treatment groups). For triple therapy and dual therapy, a similar proportion of patients reported a drug-related adverse event (23% vs 17-33%, respectively).

CONCLUSIONS

In patients with active or a recent history of duodenal ulcer, a 14-day course of lansoprazole-based triple therapy without additional acid suppression therapy is highly effective in the eradication of H. pylori and in preventing ulcer recurrence. Among the dual therapies, higher eradication rates occurred when lansoprazole (with amoxicillin) or clarithromycin (with lansoprazole) was administered t.i.d. vs b.i.d., but the rates were still significantly lower than with lansoprazole triple therapy with all three drugs administered b.i.d.