Pharmacokinetic and pharmacodynamic interactions between omeprazole and amoxycillin in Helicobacter pylori-positive healthy subjects.

BACKGROUND: Omeprazole with amoxycillin has been used to treat Helicobacter pylori infection. It was speculated that omeprazole-induced hypoacidity enhances the antibacterial activity of amoxycillin. Limited information exists about intragastric pH and bioavailability of amoxycillin during combination therapy. No data are available about possible effects of the antibiotic on the pharmacokinetics and pharmacodynamics of omeprazole. METHODS: The study was performed in a three-way cross-over double-blind design. After a run-in period on placebo with a baseline intragastric pH-metry, 24 H. pylori-positive healthy subjects were randomly dosed with amoxycillin 750 mg b.d. + placebo, amoxycillin 750 mg b.d. + omeprazole 40 mg b.d. and omeprazole 40 mg b.d. + placebo for 5 days. On the last day of each regimen intragastric pH-metries were performed, and blood samples taken for omeprazole and amoxycillin serum profiles. RESULTS: Amoxycillin monotherapy had no acid-inhibiting effect. Median pH during combined dosing was significantly lower, compared to omeprazole monotherapy (P < 0.01). Mean serum concentrations of omeprazole and amoxycillin given alone or in combination were not different. CONCLUSIONS: High-dose omeprazole does not alter the pharmacokinetics of amoxycillin. The significantly lower intragastric pH during combination therapy might be due to the H. pylori-suppressive effect of this treatment.

Dose-response of omeprazole combined with amoxycillin on duodenal ulcer healing and eradication of Helicobacter pylori.

BACKGROUND: Combination therapy using omeprazole and amoxycillin can cure Helicobacter pylori infection, but data are controversial concerning the efficacy of this regimen. The present study investigated varying doses of omeprazole combined with a standard amoxycillin dose on duodenal ulcer healing and eradication of H. pylori, in order to find an optimal dose regimen. METHODS: H. pylori-positive out-patients (n = 231) with duodenal ulcers were treated randomly and double-blind with either omeprazole 20, 40 or 80 mg b.d. plus amoxycillin 1 g b.d. for 14 days. Patients with an unhealed ulcer after this therapy took omeprazole 20 mg o.m. for another month. RESULTS: After 2 weeks, ulcer healing rates in the three treatment groups were not statistically different (85, 82 and 93%, respectively). Treatment with omeprazole 80 mg b.d. was significantly better in curing H. pylori infection (eradication rate 69%) than treatment with omeprazole 20 and 40 mg b.d. (47 and 53%). CONCLUSIONS: Combination of either omeprazole 20 or 40 mg b.d. plus amoxycillin 1 g b.d., is not sufficiently effective to be recommended as an anti-H. pylori therapy. Omeprazole 80 mg b.d. combined with amoxycillin is more efficient and well tolerated, but better treatment options now exist to cure H. pylori infection.

Impact of Helicobacter pylori eradication on heartburn in patients with gastric or duodenal ulcer disease -- results from a randomized trial programme.

BACKGROUND: Helicobacter pylori infection has been proposed as a protective factor against the development of gastro-oesophageal reflux disease. AIM: To study heartburn and endoscopic findings before and after H. pylori eradication therapy in patients with peptic ulcer disease. METHODS: In a multicentre trial programme, patients (n = 1497) were randomized to the omeprazole triple therapy group or to the control group, and were followed for 1-6 months after treatment. Patients in whom the infection was eradicated were compared with those in whom infection persisted. The severity of heartburn was measured at baseline and at each return visit. Endoscopy was performed 6 months after therapy in two of the five studies. RESULTS: In patients with duodenal ulcer, there was a significantly lower prevalence of heartburn after successful eradication of H. pylori relative to that after failed eradication (estimated odds ratio, 0.48). The reduction in the prevalence of heartburn in patients with gastric ulcer was independent of the post-treatment H. pylori status. In studies in which ulcer relapse was included in the model, this factor emerged as a significant factor for heartburn. The observed incidence of oesophagitis at the last visit was not influenced by H. pylori status. CONCLUSIONS: Eradication of H. pylori in patients with peptic ulcer disease was associated with a reduced prevalence of heartburn. Prevention of ulcer relapse could be the true cause of this reduction.

The DU-MACH study: eradication of Helicobacter pylori and ulcer healing in patients with acute duodenal ulcer using omeprazole based triple therapy.

AIM: To investigate the efficacy of two omeprazole triple therapies for the eradication of Helicobacter pylori, ulcer healing and ulcer relapse during a 6-month treatment-free period in patients with active duodenal ulcer. METHODS: This was a double-blind, randomized study in 15 centres across Canada. Patients (n = 149) were randomized to omeprazole 20 mg once daily (O) or one of two 1-week b. d. eradication regimens: omeprazole 20 mg, metronidazole 400 mg and clarithromycin 250 mg (OMC) or omeprazole 20 mg, amoxycillin 1000 mg and clarithromycin 500 mg (OAC). All patients were treated for three additional weeks with omeprazole 20 mg once daily. Ulcer healing was assessed by endoscopy after 4 weeks of study therapy. H. pylori eradication was determined by a 13C-urea breath test and histology, performed at pre-entry, at 4 weeks after the end of all therapy and at 6 months. RESULTS: The intention-to-treat (intention-to-treat) analysis contained 146 patients and the per protocol (per protocol) analysis, 114 patients. The eradication rates were (intention-to-treat/per protocol): OMC-85% and 92%, OAC-78% and 87% and O-0% (O). Ulcer healing (intention-to-treat) was greater than 90% in all groups. The differences in the eradication and relapse rates between O vs. OMC and O vs. OAC were statistically significant (all, P < 0.001). Treatment was well tolerated and compliance was high. CONCLUSION: The OMC and OAC 1-week treatment regimens are safe and effective for eradication, healing and the prevention of relapse in duodenal ulcer patients.

One-week triple therapy with esomeprazole provides effective eradication of Helicobacter pylori in duodenal ulcer disease.

BACKGROUND: Esomeprazole is the first proton pump inhibitor to be developed as an optical isomer for the treatment of acid-related diseases. METHODS: Four hundred and forty eight duodenal ulcer patients with Helicobacter pylori infection, confirmed by 13C-urea breath test (UBT), and no current ulcer, were randomised to double-blind treatment with esomeprazole 20 mg twice daily (b.d.) (n=224) or omeprazole 20 mg b.d. (n=224), in combination with amoxicillin 1 g b.d. and clarithromycin 500 mg b.d. for 1 week (EAC and OAC, respectively). A negative UBT at both 4 and 8 weeks after completing therapy indicated successful H. pylori eradication. RESULTS: Intention-to-treat (ITT) analysis comprised 400 patients (EAC, n=204; OAC, n=196) and per protocol (PP) analysis 377 patients (EAC, n=192; OAC, n=185). Eradication rates (95% confidence intervals) for ITT and PP populations were: EAC, 90% (85-94%) and 91% (86-94%); OAC, 88% (82-92%) and 91% (86-95%). Between-group differences in eradication rates were not statistically significant. Both regimens were well tolerated, with an adverse event profile and frequency typical of proton pump inhibitor plus antibiotic combination therapy. CONCLUSIONS: Esomeprazole-based triple therapy for 1 week is highly effective in eradicating H. pylori infection in duodenal ulcer disease, offers comparable efficacy to omeprazole-based therapy, and is well tolerated.

One week of treatment with esomeprazole-based triple therapy eradicates Helicobacter pylori and heals patients with duodenal ulcer disease.

BACKGROUND: Proton pump inhibitor (PPI) monotherapy is commonly continued for 3 weeks after Helicobacter pylori eradication with PPI-based triple therapy regimens to ensure duodenal ulcer (DU) healing. This randomized, double-blind, multicentre study evaluated whether only 1 week of triple therapy with the new PPI esomeprazole was sufficient to ensure high rates of ulcer healing and H. pylori eradication. METHODS: A total of 446 H. pylori-positive patients with active DU received twice daily treatment with esomeprazole 20 mg (n = 222) or omeprazole 20 mg (n = 224) in combination with amoxicillin 1 g and clarithromycin 500 mg for 1 week (EAC and OAC, respectively). Patients in the OAC group then received 3 weeks' monotherapy with omeprazole 20 mg once daily; those treated with EAC received placebo. Ulcer healing was assessed by endoscopy on completion of therapy and H. pylori status was assessed by (13)C-urea breath testing and histology 4-6 weeks later. RESULTS: Ulcer healing rates (95% CI) for intention-to-treat and per-protocol populations were: EAC + placebo 91% (87-95%) and 94% (90-97%); OAC + omeprazole 92% (88-95%) and 96% (92-98%). Corresponding H. pylori eradication rates were: EAC + placebo 86% (81-90%) and 89% (84-93%); OAC + omeprazole 88% (83-92%) and 90% (85-93%). Both eradication regimens were well tolerated, and patient compliance was high. CONCLUSIONS: A 1-week regimen of esomeprazole-based triple therapy is sufficient for DU healing and H. pylori eradication in patients with DU disease.

Randomised study of the efficacy of omeprazole and clarithromycin with either amoxycillin or metronidazole in the eradication of Helicobacter pylori in screened primary care patients.

BACKGROUND: Population Helicobacter pylori screening and treatment has been advocated as a means of reducing mortality from gastric cancer. The optimum Helicobacter pylori eradication therapy to use in this setting is uncertain. AIMS: To compare efficacy of seven days of omeprazole, clarithromycin and either metronidazole, or amoxycillin in Helicobacter pylori positive subjects detected by population screening. PATIENTS: Helicobacter pylori positive patients from the placebo group of a population screening and treatment trial were invited to take part in the investigation. METHODS: Patients were randomised to receive either omeprazole, clarithromycin and metronidazole or omeprazole, clarithromycin and amoxycillin, and Helicobacter pylori eradication was verified with a 13C-urea breath test at least four weeks after completion of therapy. RESULTS: A total of 221 patients took part in the study and 210 completed the protocol. Treatment was successful in 93/111 [84%) patients allocated to omeprazole, clarithromycin and metronidazole and in 96/110 (87%) allocated to omeprazole, clarithromycin and amoxycillin in an intention-to-treat analysis (p=0.46). Per protocol eradication rates were 93/107 (87%) in the metronidazole, and 96/103 (93%) amoxycillin group (p=0.129). CONCLUSIONS: There was no significant difference between the two regimens. The eradication rates achieved are comparable with previous studies in both dyspepsia and peptic ulcer patients.

The production and release of an extracellular polysaccharide during starvation of a marine Pseudomonas sp. and the effect thereof on adhesion.

A marine Pseudomonas sp. S9 produced and released an extracellular polysaccharide during complete energy and nutrient starvation in static conditions. The presence of the polysaccharide on the cell surface, demonstrable by immune transmission electron microscopy, correlated with changes in the degree of adhesion to hydrophobic surfaces. Polysaccharide coated cells showed a lower degree of adhesion than did cells devoid of the polymer. After 10 h of starvation, no ruthenium red stained antibody stabilized polysaccharides could be observed on the cell surface. The polysaccharide was not produced during growth since lysates of mid-log phase cells did not precipitate the antiserum. The relative proportions of sugars in the polysaccharide were 28% glucose, 35% N-acetyl-glucosamine and 37% N-acetylgalactosamine. The released polysaccharide did not significantly alter the physical parameters of surface tension and viscosity of the starvation regime. Cells starved in agitated conditions did not produce any extracellular polysaccharides and exhibited a different adhesion pattern to hydrophobic surfaces.

Starvation-specific formation of a peripheral exopolysaccharide by a marine Pseudomonas sp., strain S9.

The marine bacterium Pseudomonas sp. strain S9 produces exopolysaccharides (EPS) during both growth and total energy source and nutrient starvation. Transmission electron microscopy of immunogold-labeled cells demonstrated that the EPS is closely associated with the cell surface during growth (integral EPS), while both the integral form and a loosely associated extracellular (peripheral) form were observed during starvation. Formation and release of the latter rendered the starvation medium viscous. In addition, after 3 h of starvation in static conditions, less than 5% of the cells were motile, compared with 100% at the onset of starvation and approximately 80% subsequent to release of the peripheral EPS at 27 h of starvation. Inhibition of protein synthesis with chloramphenicol added before 3 h of starvation caused no increase in viscosity. However, addition of chloramphenicol at 3 h did not prevent the subsequent increase in viscosity displayed by S9 cells. The amount of integral EPS increased for both nontreated and chloramphenicol-treated S9 cells during the first hour of starvation, with a subsequent equal decrease. The chloramphenicol-treated cells, as well as cells of a transposon-generated mutant strain deficient in peripheral EPS formation, remained adhesive to a hydrophobic inanimate surface during the initial 5 h of starvation, whereas nontreated wild-type cells had progressively decreased adhesion capacity. During the initial 5 h of starvation, most of the nontreated cells but only a small fraction of the chloramphenicol-treated and mutant cells detached from the hydrophobic substratum.(ABSTRACT TRUNCATED AT 250 WORDS)

Antimicrobial susceptibility testing of Helicobacter pylori in a large multicenter trial: the MACH 2 study.

Culture and susceptibility testing of Helicobacter pylori strains was performed in a large multinational, multicenter randomized clinical trial. Culture was carried out on gastric biopsy samples obtained from 516 patients at entry and had a sensitivity of 99% when the [(13)C]urea breath test was used as a reference. Susceptibility testing was performed for clarithromycin and metronidazole on 485 strains by an agar dilution method and the epsilometer test (Etest) and for amoxicillin by an agar dilution method only. Resistance to clarithromycin (>1 microgram/ml) was found in 3% of the H. pylori strains, with a perfect correlation between Etest and agar dilution methods. Resistance to metronidazole (>8 microliter/ml) was found in 27% of the strains by agar dilution, but there were important discrepancies between it and the Etest method. No resistance to amoxicillin was found. The logarithms of the MICs of the three antibiotics against susceptible strains had a distribution close to normal. The impact of resistance was tested in the four arms of the trial. There were not enough clarithromycin-resistant strains to evaluate the impact of resistance on the cure rate of clarithromycin-based regimens. For metronidazole-resistant strains, the impact noted in the clarithromycin-metronidazole arm was partially overcome when omeprazole was added (76% eradication for resistant strains versus 95% for susceptible strains). Secondary resistance to clarithromycin occurred in strains from 12 of 105 patients (11.4%) after the failure of a clarithromycin-based regimen to effect eradication. The detection of point mutations in clarithromycin-resistant strains was performed by a combination of PCR and restriction fragment length polymorphism. Mutations (A2142G and 2143G) were found in all strains tested except one. This study stresses the importance of performing susceptibility tests in clinical trials in order to explain the results of different treatments.

The MACH2 study: role of omeprazole in eradication of Helicobacter pylori with 1-week triple therapies.

BACKGROUND & AIMS: The role of omeprazole in triple therapy and the impact of Helicobacter pylori resistance on treatment outcome are not established. This study investigated the role of omeprazole and influence of primary H. pylori resistance on eradication and development of secondary resistance. METHODS: Patients (n = 539) with a history of duodenal ulcer and a positive H. pylori screening test result were randomized into 4 groups. OAC group received 20 mg omeprazole, 1000 mg amoxicillin, and 500 mg clarithromycin; OMC group received 20 mg omeprazole, 400 mg metronidazole, and 250 mg clarithromycin; and AC (amoxicillin, 1000 mg, and clarithromycin, 500 mg) and MC (metronidazole, 400 mg, and clarithromycin, 250 mg) groups received no omeprazole. All doses were administered twice daily for 1 week. H. pylori status was assessed before and after therapy by 13C-urea breath test. Susceptibility testing was performed at entry and in patients with persistent infection after therapy. RESULTS: Eradication (intention to treat [n = 514]/per protocol [n = 449]) was 94%/95% for OAC, 26%/25% for AC (P < 0.001), 87%/91% for OMC, and 69%/72% for MC (P < 0.001). Primary resistance was 27% for metronidazole, 3% for clarithromycin, and 0% for amoxicillin. Eradication in primary metronidazole-susceptible/-resistant strains was 95%/76% for OMC and 86%/43% for MC. Secondary metronidazole and clarithromycin resistance each developed in 12 patients: 8 treated with omeprazole and 16 without omeprazole. CONCLUSIONS: Addition of omeprazole achieves high eradication rates, reduces the impact of primary resistance, and may decrease the risk of secondary resistance compared with regimens containing only two antibiotics.

Eradication of Helicobacter pylori using one-week triple therapies combining omeprazole with two antimicrobials: the MACH I Study.

BACKGROUND: Eradication of Helicobacter pylori provides potential cure in the majority of patients with peptic ulcer disease, and eradication rates of more than 90% have been reported, using omeprazole in combination with two antimicrobials. The choice of antimicrobials, dose regimen and duration of treatment have varied between studies, however, and an optimal treatment still has to be established. MATERIALS AND METHODS: We conducted an international, randomized, double-blind, placebo-controlled study involving more than 100 patients in each of six treatment groups in 43 hospital gastrointestinal units in Canada, Germany, Ireland, Sweden, and the United Kingdom. Patients (n = 787) with proved duodenal ulcer disease were randomized to treatment twice daily for 1 week with omeprazole, 20 mg (O), plus either placebo (P) or combinations of two of the following antimicrobials: amoxicillin, 1 gm (A), clarithromycin, 250 or 500 mg (C250, C500), or metronidazole, 400 mg (M). Eradication of H. pylori was evaluated by 13C-UBT, performed before and 4 weeks after treatment cessation. RESULTS: The eradication rates for the all-patients-treated analysis were 96%, OAC500; 95%, OMC250; 90%, OMC500; 84%, OAC250; 79%, OAM; and 1%, OP. OAC500 and OMC250 achieved eradication rates with lower 95% confidence interval limits exceeding 90%. All regimens were well-tolerated, 96% of patients complied with their dose regimen, and 2.3% of the patients discontinued treatment owing to adverse events. CONCLUSIONS: Omeprazole triple therapies given twice daily for 1 week produce high eradication rates, are well-tolerated, and are associated with high patient compliance. The two most effective therapies were those combining omeprazole, 20 mg, with either amoxicillin, 1 gm, plus clarithromycin, 500 mg, or metronidazole, 400 mg, plus clarithromycin, 250 mg, all given twice daily.