Canadian Helicobacter Study Group Consensus Conference on the Approach to Helicobacter pylori Infection in Children and Adolescents

Gastric infection with Helicobacter pylori is common in both children and adults, but children are considerably less susceptible to peptic ulcers and other pathological sequelae. As a result, the risk to benefit ratio of diagnostic studies and therapeutic regimens for H pylori in adults are likely different from those in pediatric populations. These guidelines for the management of pediatric H pylori infection, developed by the Canadian Helicobacter Study Group, are designed to identify when the diagnosis and treatment of H pylori may improve patient care. Given the low prevalence of this infection in Canada, it is important to recognize that indiscriminate testing and treatment programs in children are not recommended, and indeed may threaten the optimal care of children. Diagnostic tests should be employed judiciously and be reserved for children who are most likely to derive measurable benefit, such as those likely to have peptic ulcer disease. At this time a test and treat strategy in children cannot be considered prudent, evidence based or cost effective. It is appropriate to limit diagnosis and treatment to children and adolescents in whom H pylori has been identified during endoscopic investigation.

Development of a health-related quality-of-life questionnaire for individuals with gastroesophageal reflux disease: a validation study

This study was conducted to test the psychometric properties of a newly developed health-related quality-of-life (HRQoL) questionnaire. A total of 172 symptomatic GERD patients completed a 57-item questionnaire (containing the SF-12; symptom frequency/bothersomeness; problems related to activities, sleep, work disability; overall HRQoL; and treatment satisfaction) at baseline, week 1 [retest (N = 25)], and week 4 [follow-up (N = 100)]. Internal-consistency reliability was acceptable for most scales (range: 0.74-0.92). Test-retest reliability was acceptable for most scales (ICC: 0.74-0.85). Construct validity was demonstrated based on observed correlations. Known-groups validity was upheld, as patients who experienced more symptom days and patients who reported higher pain reported worse HRQoL than those with less symptoms or less severe pain. When categorized according to change in pain severity, Guyatt's statistic for the "improved" and "worse" groups demonstrated responsiveness, although many of the scales for the "stable" group were also responsive. In conclusion, the HRQoL questionnaire was found to be reliable, valid, and responsive.

Treatment after failure: the problem of "non-responders"

Although the currently most effective treatment regimens cure about 90% of infections, 10% of patients remain Helicobacter pylori positive. Several factors contribute to treatment failure. These include patient compliance, bacterial resistance to antibiotics, and treatment related issues. Treatment failure leads to the development of bacterial resistance to metronidazole and clarithromycin. Retreatment can be undertaken after considering several different strategies: to repeat the same regimen with full doses of medications and a longer treatment duration, or to choose different regimens to avoid the antibiotic previously used, or to switch to proton pump inhibitor (PPI) based quadruple therapy or ranitidine bismuth citrate (RBC) based triple therapy. In principle, full doses and longer treatment durations are advisable. As retreatment is always difficult, choosing the best available first line treatment regimen is still the best "rescue" treatment.

The importance of clarithromycin dose in the management of Helicobacter pylori infection: a meta-analysis of triple therapies with a proton pump inhibitor, clarithromycin and amoxycillin or metronidazole

BACKGROUND

It is not clear which dose of clarithromycin (500 mg b.d. or 250 mg b.d.) is more effective for Helicobacter pylori eradication in proton pump inhibitor-based triple therapies.

METHODS

We undertook a meta-analysis of the effect of 7-day triple therapies consisting of a proton pump inhibitor (P), and clarithromycin (C) and amoxycillin (A) or metronidazole (M). A meta-analysis of all clinical trials performed in an adult population and published in English up to March 1998 was undertaken. Studies with doses of clarithromycin 500 mg b.d. or 250 mg b.d. only were included.

RESULTS

A total of 82 studies (31 papers and 51 abstracts) involving 110 treatment arms and 6123 patients were analysed that met the predetermined inclusion and exclusion criteria. In the PAC combination, the pooled eradication rate in patients treated with clarithromycin 500 mg b.d. was 89.5% (95% CI: 86.9-92. 0%) by per protocol analysis and 86.6% (95% CI: 81.0-89.3%) by intention-to-treat analysis. These rates are significantly higher than those achieved with clarithromycin 250 mg b.d. (83.3% by per protocol and 78.2% by intention-to-treat analysis, both P < 0.0001). This difference was confirmed in head-to-head comparative studies. In the PMC regimen, clarithromycin 500 mg b.d. eradicated 90.8% (95% CI: 87.0-94.5%) of the infections compared to 88.5% (95% CI: 85.5-91. 5%) in patients treated with clarithromycin 250 mg b.d. by per protocol analysis (P = 0.082). The corresponding rates by intention-to-treat analysis for clarithromycin 500 mg b.d. and 250 mg b.d. was 88.3% and 86.7%, respectively (P = 0.259).

CONCLUSIONS

Seven-day triple therapies with a proton pump inhibitor, clarithromycin and amoxycillin or metronidazole are highly effective treatments for the eradication of H. pylori. Clarithromycin 500 mg b. d. should be used in these combinations to achieve the best first treatment results, which can minimize the subsequent development of bacterial resistance to clarithromycin and metronidazole.

Importance of pH control in the management of GERD

The degree of esophageal mucosal injury that occurs in patients with gastroesophageal reflux disease depends on duration of exposure and pH of the refluxate. Evidence suggests that an intraesophageal pH of less than 4.0 directly correlates with the degree of mucosal injury. The advent of acid secretory inhibitors such as the histamine2-receptor antagonists (H2RAs) and, more recently, the proton pump inhibitors (PPIs) has revolutionized the treatment of patients with reflux disease. However, the evidence linking the degree of mucosal damage to pH of the refluxate has prompted investigators to reevaluate the effectiveness of these agents. The PPIs are significantly more effective than the H2RAs in achieving and sustaining an intragastric pH above 4.0. The results of clinical trials performed with the PPIs indicate a faster rate of healing of erosive esophagitis and of symptom relief than treatment with H2RAs.

Cytogenetic evidence for a species complex within Anopheles pseudopunctipennis theobald (Diptera: Culicidae)

Anopheles pseudopunctipennis was collected from Acapulco, Mexico and Sallee River, Grenada, West Indies and used in cross-mating experiments. Larvae from the cross, Mexico female X Grenada male, died in the third instar. However, adult progeny were obtained from the reciprocal cross Grenada female x Mexico male. These hybrid males had testes with apparently normal appearance but some without viable sperm. Polytene chromosomes obtained from hybrid females exhibited extensive asynapsis of the X chromosomes. Previously undescribed fixed inversion differences between the two populations were noted on the X chromosome. It is concluded that the two populations belong to different species. The Grenada population is designated An. pseudopunctipennis species C, since it is the third taxon recognized in this species complex.

Canadian Helicobacter pylori Consensus Conference update: infections in adults. Canadian Helicobacter Study Group

The first Canadian Helicobacter pylori Consensus Conference took place in April 1997. The initial recommendations of the conference were published in early 1998. An update meeting was held in June 1998, and the present paper updates and complements the earlier recommendations. Key changes included the following: the recommendation for testing and treating H pylori infection in patients with known peptic ulcer disease was extended to testing and treating patients with ulcer-like dyspepsia; it was decided that the urea breath test (not serology) should be used for routine diagnosis of H pylori infection unless endoscopy is indicated for another reason; and recommended therapies were a twice daily, seven-day regimen of a proton pump inhibitor (omeprazole 20 mg, lansoprazole 30 mg, pantoprazole 40 mg) or ranitidine bismuth citrate 400 mg, plus clarithromycin 500 mg and amoxicillin 1000 mg, or plus clarithromycin 500 or 250 mg and metronidazole 500 mg. The need was reiterated to have funding for readily accessible, accurate testing for H pylori infection with the urea breath test. It was strongly recommended that regional centres be established to monitor the prevalence of antibiotic-resistant H pylori infections. The initial consensus document referred to pediatric issues that were not addressed in this update but were the subject of a subsequent Canadian Helicobacter Study Group meeting, and will be published later in 1999.

Anti-ulcerogenic properties of endothelin receptor antagonists in the rat

BACKGROUND

Endothelins have been implicated in gastric mucosal damage in a variety of animal models. Exogenous ET-1 and ET-3 are causally associated with experimental gastric ulcers. Furthermore, clinical reports also show elevated plasma and gastric mucosal endothelin-1 levels in patients suffering from peptic ulcers.

AIM

To study the possibility that endothelin receptor antagonists may have beneficial effects and prevent the development of gastric ulcers. We have tested in rats the orally-active endothelin antagonist bosentan (Ro 47-0203) and Ro 48-5695, which is 10-30 times more potent than bosentan on endothelin receptors.

METHODS

Water immersion restrained stress (WIRS) and indomethacin were used to provoke gastric mucosal damage. Endothelin receptor antagonists were administered orally prior to the induction of gastric damage. The gastric lesion index (mm), assessed macroscopically, and myeloperoxidase (MPO) activity were used as markers of the extent of mucosal injury.

RESULTS

Bosentan at 100 and 30 mg/kg administered orally caused attenuation of gastric damage in the WIRS model by 58% and 42%, respectively. Bosentan also caused complete reduction of MPO activity. In indomethacin-induced gastric damage, 100 mg/kg bosentan attenuated gastric damage by 45% and 61% as measured by the gastric lesion index and MPO activity respectively. Ro 48-5695 was at least 30 times more potent than bosentan in reducing indomethacin-induced mucosal damage and at 3 mg/kg, caused a decrease of 49% in the gastric lesion index and a reduction in MPO activity of 41%. Bosentan and Ro 48-5695 possess weak antisecretory properties as tested in the mouse gastric gland assay, than cannot, alone, account for their anti-ulcer properties.

CONCLUSIONS

Both endothelin receptor antagonists prevented the development of gastric mucosal injury in the rat. Disturbances in the gastric microcirculation are responsible for the development of experimental gastric ulcers. The anti-ulcer properties of these two endothelin antagonists suggest possible new therapeutic approaches to controlling gastric inflammation.

A systematic overview of the use of diary cards, quality-of-life questionnaires, and psychometric tests in treatment trials of Helicobacter pylori-positive and -negative non-ulcer dyspepsia

BACKGROUND

Our aim was to evaluate the use of diary cards, quality-of-life questionnaires, and psychometric tests in treatment trials of non-ulcer dyspepsia.

METHODS

Data sources were a Medline search (up to 1966) and a manual search of five gastrointestinal journals (up to 1980) for original, randomized, double-blind, placebo-controlled trials with at least 20 patients which evaluated treatment regimens for non-ulcer dyspepsia.

RESULTS

Of the 67 eligible studies, 31 used diary cards. Diary cards were used alone in 15 of the 31 studies (48%), whereas the others (52%) also used a physician assessment. The symptoms assessed by diary cards were epigastric pain (100%), nausea/vomiting (65%), heartburn (52%), belching (39%), regurgitation (29%), fullness (29%), and bloating (23%). Forty-five per cent also recorded antacid use. Severity of outcome measures was assessed by a visual analogue scale in 5 of the 31 studies (16%), Likert scales in 17 studies (55%), and unclear methods in 3 studies (10%). For statistical analysis daily averages of symptoms were used in 5 of the 31 studies (16%), weekly averages in 11 studies (35%), and 2-week intervals during the treatment period in the rest, with some studies using a combination (such as daily and weekly averages). Only 3 of the 31 studies (8%) checked for compliance with diary card data. None of the studies mention anything about missing data and how this was handled. One study evaluated quality of life questionnaires and one evaluated a psychometric test.

CONCLUSIONS

Non-ulcer dyspepsia treatment trials frequently use diary cards but need to be much clearer about how information was obtained and how it was used in the statistical analysis. Not much information is available to comment on the use of quality-of-life questionnaires or psychometric tests for evaluation of outcome measures.

Single-strand conformation polymorphism analysis for identification of four members of the Anopheles funestus (Diptera: Culicidae) group

Members of the Anopheles funestus Giles group are difficult to identify because of the morphological overlap that exists within the group. This inability to distinguish species, as well as the fact that the species vary in their behavior and biting preferences, complicate the successful planning and maintaining of malaria control programs. In this article we discuss the use of a single-strand conformation polymorphism (SSCP) assay to distinguish 4 members of the An. funestus group collected at 10 different localities in Africa. rDNA genes differ at numerous sites among closely related species. Using conserved primers, the D3 domain in the 28S gene was amplified, electrophoresed on SSCP gels, and species-specific patterns were observed. Intraspecific variation was detected in An. funestus specimens from East and West Africa. Analyzing 108 An. funestus, 78 An. vaneedeni Gillies & Coetzee, 21 An. rivulorum Leeson, and 2 An. lessoni Evans, we concluded that SSCPs can be used successfully as a molecular tool for the identification of these species.

The case for treatment of dyspeptic patients infected with H. pylori

H. pylori is probably the commonest bacterial infection worldwide and associated with a number of clinical outcomes including chronic active gastritis, peptic ulcer, gastric adenocarcinoma, gastric MALT lymphoma and possibly dyspepsia. Treatment to eradicate H. pylori infection has changed significantly the natural history of peptic ulcer disease and is now the recommended approach to patients with non-NSAID gastric and duodenal ulcers. Controversies remain as to whether H. pylori infection is a cause of dyspepsia and non-ulcer dyspepsia. However, results from several economic models evaluating a "test and treat" strategy have suggested that eradication of H. pylori infection as an initial choice is the most cost-effective approach and has a long-term benefit in a significant proportion of patients with dyspepsia. The conclusion of H. pylori as a group 1 human carcinogen by the IARC and the subsequent analyses have added further to the recommendation for eradication of the infection.

Accurate flow cytometric membrane potential measurement in bacteria using diethyloxacarbocyanine and a ratiometric technique

BACKGROUND

Membrane potential (MP) plays a critical role in bacterial physiology. Existing methods for MP estimation by flow cytometry are neither accurate nor precise, due in part to the heterogeneity of size of the particles analyzed. The ratio of a size- and MP-sensitive measurement, and an MP-independent, size-sensitive measurement, should provide a better estimate of MP.

METHODS

Flow cytometry and spectrofluorometry were used to detect red (488 --> 600 nm) fluorescence associated with aggregates of diethyloxacarbocyanine (DiOC2(3)), which, in the monomeric state, is normally green (488 --> 530 nm) fluorescent.

RESULTS

In bacteria incubated with 30 microM dye, aggregate formation increases with the magnitude of the interior-negative membrane potential. Green fluorescence from stained bacteria predominantly reflects particle size, and is relatively independent of MP, whereas red fluorescence is highly dependent on both MP and size. The ratio of red to green fluorescence provides a measure of MP that is largely independent of cell size, with a low coefficient of variation (CV). Calibration with valinomycin and potassium demonstrates that the method is accurate over the range from -50 mV through -120 mV; it also accurately tracks reversible reductions in MP produced by incubation at 4 degrees C and washing in glucose-free medium.

CONCLUSIONS

The ratiometric technique for MP estimation using DiOC2(3) is substantially more accurate and precise than those previously available, and may be useful in studies of bacterial physiology and in investigations of the effects of antibiotics and other agents on microorganisms.

pH, healing rate, and symptom relief in patients with GERD

Gastroesophageal reflux symptoms are common and occur in all of us from time to time. In others, reflux may be associated with ulcerative esophagitis. The symptoms may be aggravated by large meals, coffee, smoking and position. Physiological and pathological reflux can be separated by the frequency and duration of the exposure of the lower esophagus to acid. Pathological reflux results in symptoms and also esophagitis and ulceration in some patients. Although gastroesophageal reflux disease (GERD) is considered to result from a disorder of motility in the esophagus, gastric acid and peptic activity are deemed pivotal to the initiation and continuation of the esophageal damage and the development of symptoms. Acid exposure in the esophagus is normally less than 4 percent of the 24 hours with a pH below 4. An increase over 4 percent of the time with a pH less than 4 is considered pathological. Hence, antisecretory drugs have become the principle approach to the treatment of reflux symptoms and esophagitis since they reduce the acidity, of gastric juice and the activity of pepsin. Importantly, they also reduce the volume of gastric juice available for reflux into the esophagus. There is a clear relationship between the degree and duration of acid suppression and the relief of heartburn and healing of esophagitis. Pharmacodynamic studies with different dose regimens of the H2-receptor antagonists and the proton pump inhibitors show a difference in the degree and duration of the antisecretory effect, and this correlates closely with the results of clinical trials with respect to the healing of esophagitis and the relief of symptoms. Proton pump inhibitors achieve healing rates by week four, which are not achieved by H2-receptor antagonists even after 12 weeks of treatment. The advantage of proton pump inhibitors over H2-receptor antagonists is due to the greater degree, longer duration of effect and more complete inhibition of acid secretion that maintains intragastric pH above 4 for a maximal duration. Although there is no significant difference between proton pump inhibitors with respect to healing of esophagitis, symptom relief occurs earlier with lansoprazole than omeprazole, and this is probably due to the greater oral bioavailability and faster onset of action of lansoprazole when compared to omeprazole.

Torsion-Rotation Energy Levels and the Hindering Potential Barrier for the Excited Vibrational State of the OH-Stretch Fundamental Band nu1 of Methanol

The absorption spectrum of methanol vapor has been recorded at room temperature from 3200 to 4200 cm-1 with a 1.24-M path-difference Fourier transform spectrometer. Over 10 000 transitions to the torsion-rotation states n, tau J, K of the OH stretching fundamental band nu1 have been assigned, thereby greatly expanding the results of previous investigations. Approximately 4000 of the cleaner lines have been used to determine 665 excited state torsion-rotation levels with principal torsional quantum number n = 0 as well as 494 levels with n = 1, 286 levels with n = 2, and 14 levels with n = 3. These levels correspond to 86 values of the quantum numbers n, tau, K. Most of the levels of a given n, tau, K are perturbed resulting in irregular P-, Q-, and R-branch series. The J = 0 origins for 64 values of n, tau, K have been fitted and a value of 410 cm-1 obtained for the hindering potential barrier. This is in agreement with a previous study of grating spectra but is lower than that obtained in more recent analyses of n = 0 <-- 0 transitions observed for K </= 3 in very low temperature spectra. The criteria used here to select states to be fitted and the difficulties in estimating the J = 0 origins because of the many perturbing level crossings are discussed. Copyright 1998 Academic Press.

Review article: olestra and its gastrointestinal safety

Olestra is a fat substitute made from sucrose and vegetable oil. Olestra is neither digested nor absorbed, and therefore adds no calories or fat to the diet. Because the gut is the only organ that is exposed to olestra, the potential for olestra to affect gastrointestinal structure and function, and the absorption of nutrients from the gut, has been investigated. Histological evaluations performed after long-term feeding studies have shown no indications that olestra causes injury to the gastrointestinal mucosa. Olestra is not metabolized by the colonic microflora, and has no meaningful effects on the metabolic function of these organisms. Studies of gastrointestinal transit have shown that the consumption of olestra with food does not affect gastric emptying, or small or large bowel transit times. Olestra does not affect the absorption of macronutrients, water-soluble vitamins or minerals. It causes a dose-responsive decrease in the availability of the fat-soluble vitamins A, D, E and K; however, this potentially adverse effect is offset by the addition of vitamins to olestra-containing foods. Olestra has no consistent effect on the amount of total bile acids excreted in the faeces, and therefore probably has no significant effect on bile acid absorption. The occurrence of gastrointestinal symptoms, including diarrhoea, loose stools, gas and abdominal cramping, after consumption of olestra under ordinary snacking conditions is comparable to that following consumption of triglyceride-containing snacks.

The Second Canadian Gastroesophageal Reflux Disease Consensus: moving forward to new concepts

Gastroesophageal reflux disease (GERD) is a disease with serious consequences that may result in significant impairment in quality of life and disease morbidity. Across all grades of severity of symptoms and severity of underlying esophageal disease, proton pump inhibitors (PPIs) provide therapeutic gains over prokinetics (PKs) or H2 receptor antagonists (H2RAs). The potential cost effectiveness of using medications with higher acquisition costs that may lower health care costs overall is often disregarded when conducting cost comparisons with medications having lower 'up-front' costs. Limiting therapy to less effective agents condemns many patients to protracted suffering, repeated physician visits and needless reinvestigation of symptoms that could have been resolved by appropriate initial therapy. Based on current data, use of any classification of symptom severity as a basis for selecting one class of therapeutic agents over another for first line therapy (i.e. PKs, H2RAs for 'mild' GERD, versus a PPI for 'severe' disease) is unwarranted.

Description of Anopheles (Cellia) seretsei sp. nov. from Kasane, Botswana

Anopheles (Cellia) seretsei, a new mosquito species from Kasane, northern Botswana, is described on the basis of the examination of a type series of 37 females and 18 males. Diagnostic features of the egg, larva, and pupa are presented. Comparisons of the new species with close relatives (Anopheles listeri and Anopheles azevedoi) are made.

Bionomics and cytogenetics of Anopheles seretsei Abdulla-Khan, Coetzee, and Hunt, a new species from northern Botswana

Morphological analysis of anopheline mosquitoes from Kasane, Botswana, revealed a new species, Anopheles seretsei, that is closely related to Anopheles azevedoi and Anopheles listeri. A description of the type locality and biological characteristics of An. seretsei is given. Comparisons are made with An. listeri and An. azevedoi. The banding patterns of the giant polytene chromosomes of An. seretsei were compared with those of An. listeri and found to be homosequential.

Hpall endonuclease distinguishes between two species in the Anopheles funestus group

The Anopheles funestus group consists of at least eight species that are currently identified mainly on morphological criteria. Until recently, only An. funestus s.s. was implicated in the transmission of malaria in Africa, but recent work in Tanzania has shown that An. rivulorum is also involved, albeit to a lesser degree than An. funestus. The constraints in the identification of the species and the need to clarify better their epidemiological role have led to the development of a PCR-RFLP method for the identification of two anthropophilic members of the group. Using PCR primers developed from the D3 region in the 28S ribosomal gene, amplified products were digested with the restriction endonuclease Hpall. This produced two distinct fragments on an agarose gel that could be used to separate An. funestus from An. vaneedeni. The technique needs to be tested on natural populations of these two species as well as on other members of the An. funestus group.

Meta-analysis of the relationship between Helicobacter pylori seropositivity and gastric cancer

BACKGROUND & AIMS

Reports in the literature regarding the relationship of Helicobacter pylori infection to gastric cancer are conflicting. The aim of this study was to identify the source of heterogeneity between studies.

METHODS

Meta-analysis of cohort or case-control studies with age- and/or sex-matched controls, providing raw data on H. pylori infection detected by serology, was used.

RESULTS

A fully recursive literature search identified 19 qualified studies with 2491 patients and 3959 controls. Test for homogeneity found a significant difference in odds ratio between patients with early and advanced gastric cancer (6.35 vs. 2.13; P = 0.01), patients with cardiac and noncardiac gastric cancer (1.23 vs. 3.08; P = 0.003), and population- and hospital-based controls (2.11 vs. 1.49; P < 0.001). The summary odds ratio for gastric cancer in H. pylori-infected patients is 1.92 (95% confidence interval [CI], 1.32-2.78), 2.24 (95% CI, 1.15-4.4), and 1.81 (95% CI, 1.16-2.84) for all studies, cohort, and case-control studies, respectively. H. pylori-infected younger patients have a higher relative risk for gastric cancer than older patients with odds ratios decreasing from 9.29 at age < or = 29 years to 1.05 at age > or = 70 years. H. pylori infection is equally associated with the intestinal or diffuse type of gastric cancer.

CONCLUSIONS

H. pylori infection is a risk factor for gastric cancer. The heterogeneity of reported results is caused by differences in the selection of controls, patient age, and the site and stage of gastric cancer.

Dose-response relationship of lansoprazole to gastric acid antisecretory effects

BACKGROUND

Proton pump inhibitors have been found to be effective in numerous studies in patients with peptic ulcer disease, particularly associated with Helicobacter pylori and gastro-oesophogeal reflux disorders. Optimal healing rates of antisecretory therapy for peptic acid disease is dependent upon the degree and duration of acid suppression and the length of treatment.

OBJECTIVE

To evaluate the extent and duration of gastric acid suppression of several lansoprazole regimens, administered for 5 consecutive days in 32 healthy adult male subjects.

METHODS

Intragastric 24-h pH monitoring was performed in 32 healthy subjects in a randomized, double-blind, four-way crossover study. Sixteen subjects (Group 1) received lansoprazole 30 mg o.d. (once daily), 15 mg b.d. (twice daily), 30 mg b.d. and 30 mg t.d.s. (three times a day) for 5 days; and 16 subjects (Group 2) received lansoprazole 30 mg o.d., 60 mg o.d., 60 mg b.d. and 60 mg t.d.s. for 5 days.

RESULTS

Mean 24-h intragastric pH values for lansoprazole 30 mg o.d., 15 mg b.d., 30 mg b.d. and 30 mg t.d.s. were 4.47, 4.57, 5.07 and 5.63, respectively. Multiple-dose regimens of lansoprazole 30 mg b.d. and t.d.s. produced greater acid suppression compared to lansoprazole 30 mg o.d. and 15 mg b.d. There was no significant difference in acid suppression between lansoprazole 30 mg o.d. and 15 mg b.d. Mean 24-h intragastric pH values for lansoprazole 30 mg o.d., 60 mg o.d., 60 mg b.d. and 60 mg t.d.s. were 4.13, 4.45, 5.19 and 5.13, respectively. Multiple-dose regimens of lansoprazole 60 mg b.d. and t.d.s. produced significantly greater acid suppression compared to lansoprazole 30 mg o.d. and 60 mg o.d. There was no significant difference in acid suppression between lansoprazole 30 mg o.d. and 60 mg o.d. Lansoprazole 30 mg t.d.s., 60 mg b.d. and 60 mg t.d.s. produced significantly greater percentage time above pH 3, 4, 5 and 6 than did lansoprazole 30 mg o.d. Post-regimen serum gastrin values increased by 50-130% from pre-study mean values but remained within normal range and returned to pre-study values 7-14 days post-dosing.

CONCLUSIONS

Multiple-dose regimens of lansoprazole (> or =30 mg b.d. for 5 days) produce significantly increased intragastric pH and significantly longer duration of increased intragastric pH than does lansoprazole 30 mg administered once daily.