Antibacterial activity of pantoprazole and omeprazole against Helicobacter pylori

Design, synthesis, antimicrobial activity and molecular docking study of cationic bis-benzimidazole-silver(I) complexes

Two series of bis(1-alkylbenzimidazole)silver(I) nitrate and bis(1-alkyl-5,6-dimethylbenzimidazole)silver(I) nitrate complexes, in which the alkyl substituent is either an allyl, a 2-methylallyl, an isopropyl or a 3-methyloxetan-3-yl-methyl chain, were synthesized and fully characterized. The eight N-coordinated silver(I) complexes were screened for both antimicrobial activities against Gram-negative (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Acinetobacter baumannii) and Gram-positive (Staphylococcus aureus, Staphylococcus aureus MRSA, and Enterococcus faecalis) bacteria and antifungal activities against Candida albicans and Candida glabrata strains. Moderate minimal inhibitory concentrations (MIC) of 0.087 μmol/mL were found when the Gram-negative and Gram-positive bacteria were treated with the silver complexes. Nevertheless, MIC values of 0.011 μmol/mL, twice lower than for the well-known fluconazole, against the two fungi were measured. In addition, molecular docking was carried out with the structure of Escherichia coli DNA gyrase and CYP51 from the pathogen Candida glabrata with the eight organometallic complexes, and molecular reactivity descriptors were calculated with the density functional theory-based calculation methods.

Efficacy of dexlansoprazole-based triple therapy for Helicobacter pylori infections

BACKGROUND

Dexlansoprazole has been shown to be efficacious for the treatment of gastroesophageal reflux disease. However, there is a paucity of data about its efficacy for Helicobacter pylori eradication. The aim of this study was to evaluate the efficacy of dexlansoprazole for H. pylori eradication as triple therapy in real-world practice.

METHODS

Adult patients with endoscopically proven H. pylori related peptic ulcer diseases or gastritis were recruited for this study. The eradication status was assessed based on the results of the ¹³C-urea breath test performed 4 weeks after treatment. According to the different treatment regimens, the patients were allocated to group A: Esomeprazole 40 mg b.i.d. + amoxicillin 1 g b.i.d. + clarithromycin 500 mg b.i.d. for 7 days; group B: Esomeprazole 40 mg q.d. + amoxicillin 1 g b.i.d. + clarithromycin 500 mg b.i.d. for 7 days, or group C: Dexlansoprazole 60 mg q.d. + amoxicillin 1 g b.i.d. + clarithromycin 500 mg b.i.d. for 7 days.

RESULTS

A total of 215 patients (49% males) were enrolled in this study, with a mean age of 55 years. The eradication rates in group A, B, and C were 94.7% (71/75), 89.6% (69/77), and 93.7% (59/63) (p = 0.457), respectively. The adverse events were similar between the three groups (p = 0.068).

CONCLUSIONS

This study suggests that dexlansoprazole-based triple therapy has an acceptable eradication rate for H. pylori infection.

Identification of potential inhibitors of sortase A: Binding studies, in-silico docking and protein-protein interaction studies of sortase A from Enterococcus faecalis

Enterococcus faecalis (Ef) is a Gram positive multidrug resistant (MDR) bacterium contributing about 70% of total enterococcal infections. In Ef, a membrane anchored transpeptidase Sortase A plays a major role in biofilm formation. Therefore, it has been recognized as an ideal drug target against Ef. In this regard to identify the potential inhibitors of Ef Sortase A (EfSrtA_∆59), we have cloned, expressed and purified EfSrtA_∆59. We have also done the in-silico docking studies to identify lead molecules interacting with EfSrtA_∆59. Furthermore, the binding studies of these identified lead molecules were performed with EfSrtA_∆59 using fluorescence and CD spectroscopic studies. We also identified the interaction partner of EfSrtA_∆59 using STRING. Protein-protein docking studies were also performed. Docking experiment revealed that benzylpenicillin, cefotaxime, pantoprazole and valsartan were bound to same site on the protein with similar interactions. Binding studies using fluorescence spectroscopic studies confirmed the binding of all the ligands to EfSrtA_∆59, which was further validated by far and near-UV CD experiments. Thermo stability experiments validate the stability-activity trade-off hypothesis. Sequence based interaction studies identified that EfSrtA_∆59 interact with the Ef_1091, Ef_1093 and Ef_2658 proteins. Homology model of Ef_1091 and Ef_1093 was docked with modeled EfSrtA_∆59 and their interactions are also discussed.

Negative Effect of Proton-pump Inhibitors (PPIs) on Helicobacter pylori Growth, Morphology, and Urease Test and Recovery after PPI Removal--An In vitro Study

BACKGROUND

Proton-pump inhibitor (PPI) consumption does lead to false-negative results of Helicobacter pylori diagnostic tests such as biopsy culture and rapid urease test (RUT).

MATERIALS AND METHODS

Helicobacter pylori isolates from 112 dyspeptic patients with (56.5%) or without (43.5%) PPI consumption were recruited for examining the negative effects of omeprazole (OMP), lansoprazole (LPZ), and pantoprazole (PAN) on H. pylori viability, morphology, and urease, in vitro. The effect of a sublethal concentration of OMP on bacterial features and their recovery after removal of OMP was also assessed.

RESULTS

Of 112 culture-positive gastric biopsies, 87.5% were RUT positive and 12.5% RUT negative. There was a significant correlation between negative RUT results and PPI consumption (p < .05). OMP (minimum inhibitory concentration, MIC 32 μg/mL) and LPZ (MIC 8 μg/mL) inhibited the growth of 78.6% of H. pylori isolates. OMP and LPZ inhibited urease of 90.3% of isolates between 0 and 40 minutes and 54.4% between 20 and 40 minutes, respectively. PAN did not inhibit H. pylori growth and urease. Three 3-day (9 days) consecutive subcultures of H. pylori on brucella blood agar (BBA) supplemented with OMP resulted in reduced bacterial viability (1+), compared with control (4+), change of spiral morphology to coccoid, and reduction in pink color intensity in urea agar. Bacterial growth (1+), morphology, and urease test did not improve after the first 3-day and second 3-day (6 days) subcultures on BBA. However, relative recovery occurred after the third 3-day (9 days) subculture and complete recovery was observed after the fourth 3-day (12 days) subculture, as confluent growth (4+), 100% spiral cells, and strong urease test.

CONCLUSION

Proton-pump Inhibitors exert transient negative effects on H. pylori viability, morphology, and urease test. Accordingly, cessation of PPI consumption at least 12 days before endoscopy could help avoiding false-negative results of H. pylori diagnostic tests.

A Pilot Randomized Controlled Study of Dexlansoprazole MR-Based Triple Therapy for Helicobacter Pylori Infection

Dexlansoprazole MR is the R-enantiomer of lansoprazole that is delivered by a dual delayed release formulation. It is effective for symptom control of patients with gastroesophageal reflux disease. However, its efficacy in the treatment of Helicobacter pylori infection remains unclear. This pilot, randomized, controlled, head-to-head study was conducted to investigate whether the efficacy of single-dose dexlansoprazole MR-based triple therapy was noninferior to double-dose rabeprazole-based triple therapy in the treatment of H pylori infection. Consecutive H pylori-infected subjects were randomly allocated to either 7-day dexlansoprazole MR-based standard triple therapy (dexlansoprazole MR 60 mg once daily, clarithromycin 500 mg twice daily, and amoxicillin 1 g twice daily) or rabeprazole-based triple therapy (rabeprazole 20 mg twice daily, clarithromycin 500 mg twice daily, and amoxicillin 1 g twice daily). H pylori status was assessed 6 weeks after the end of treatment. A total of 177 H pylori-infected patients were randomized to receive dexlansoprazole MR-based (n = 90) or rabeprazole-based (n = 87) triple therapy. Intention-to-treat analysis demonstrated no differences between eradication rates of the 2 study groups (83.3% vs 81.6%; P = 0.736). Per-protocol analysis yielded comparable results (85.1% vs 81.2%; P = 0.497). Both groups exhibited similar frequencies of adverse events (7.8% vs 4.6%; P = 0.536) and drug compliance (98.9% vs 97.7%; P = 0.496). Multivariate analysis disclosed that the presence of clarithromycin resistance was the only independent factors predictive of treatment failure with an odds ratio of 6.8 (95% confidence interval: 1.2-37.6). This work demonstrates that single-dose dexlansoprazole MR-based triple therapy yields a similar eradication rate as double-dose rabeprazole-based therapy. Since the pharmaceutical cost of the single-dose dexlansoprazole MR regime is lower than that of the double-dose rabeprazole regimen, dexlansoprazole-based therapy can reasonably be recommended in the first-line treatment of H pylori infection.

The growth of bacteria in infusion drugs: propofol 2% supports growth when remifentanil and pantoprazole do not

BACKGROUND AND OBJECTIVES

Contamination risks of propofol 2%, remifentanil, and pantoprazole; and in vitro effects of these drugs on the growth of common infective agents in intensive care units were evaluated.

METHODS

For detection of contamination risk, drugs were prepared ready to use under intensive care unit conditions, were tested. Effects of these three drugs on bacterial growth were also investigated. Drugs were prepared at the concentrations used in the intensive care unit and inoculated with common pathogens after which they were incubated at 4°C, 22°C and 36°C. Subcultures were made at 0, 2, 4 and 8h and colony counts were evaluated. Minimum inhibitory concentration values were determined for all drugs at 4°C, 22°C and 36°C.

RESULTS

No growth was observed in the drugs prepared in the intensive care unit. Propofol tended to support while remifentanil inhibited bacterial growth. Effect of pantoprozole differed according to the bacteria tested. None of the drugs showed antibacterial activity at the maximum concentrations which may be achieved in blood of the patients.

CONCLUSION

Propofol strongly supports the growth of the microorganisms tested, although remifentanil and pantoprazole do not. Therefore, it is important to follow the strict aseptic techniques for the preparation of propofol.

Pantoprazole: a new and more specific proton pump inhibitor

Pantoprazole is the third proton pump inhibitor (PPI) to be launched for the treatment of acid-peptic diseases. Like other drugs in this class, pantoprazole causes long-lasting inhibition of acid secretion by inactivating the parietal cell H+/K+-ATPase. Compared with H2 antagonists, pantoprazole results in faster pain relief, more rapid ulcer healing, healing of resistant ulcers and far greater efficacy in oesophageal reflux disease. The three PPIs currently available display almost identical efficacy in the treatment of acid-peptic diseases and when included as part of Helicobacter pylori eradication regimes. However, pantoprazole shows improvements in selectivity and pharmacokinetic properties compared with omeprazole and lansoprazole. The bioavailability of pantoprazole is considerably higher than omeprazole, remains constant upon repeated dosing, and is unaffected by food. Significantly, pantoprazole does not influence hepatic cytochrome P450 activity and does not therefore interact with co-administered drugs. This is in contrast to omeprazole, which inhibits P450, and lansoprazole, which appears to weakly induce multiple metabolic pathways. Although pantoprazole is entering an antisecretory market dominated by omeprazole and ranitidine, it has a number of potential advantages. In this respect it is worth recalling that enhanced specificity and the absence of drug interactions were decisive factors in determining market share in the H2 antagonist era. Pantoprazole may therefore achieve significant market penetration, particularly at the expense of lansoprazole and the H2 blockers.

Potent Gastric Acid Inhibition in Helicobacter pylori Eradication

At present, antisecretory drugs--foremost among them the proton pump inhibitors (PPIs)--represent a keystone in Helicobacter pylori eradication therapy. The present article shall first compare the role of PPIs as compared with histamine H2 receptor antagonists, both of them in the role of antibiotic-associated antisecretory therapy, and shall then address the contribution of each of the various PPIs that have been developed until the present time to the H. pylori eradication therapies. In summary, it may be concluded that PPIs are more effective overall than H2 receptor antagonists when the two groups of antisecretory drugs are given at the usual standard doses together with antibiotics with the intention of eradicating H. pylori infection. However, all PPIs (omeprazole, lansoprazole, pantoprazole, rabeprazole, and esomeprazole) are equivalent when given together with two antibiotics to cure the infection.

Pantoprazole based therapies in Helicobacter pylori eradication: a systematic review and meta-analysis

AIM

To perform a systematic review on the efficacy of pantoprazole based therapies in Helicobacter pylori eradication, and to conduct a meta-analysis comparing the efficacy of pantoprazole and other proton pump inhibitors (PPIs) when co-prescribed with antibiotics.

METHODS

Studies evaluating pantoprazole combined with antibiotics were considered. Only randomized clinical trials comparing pantoprazole and other PPIs when co-prescribed with antibiotics, and differing only in the PPI (pantoprazole vs other), were eligible for inclusion in the meta-analysis. Bibliographical searches in several electronic databases, and manual search of abstracts from congresses, were conducted. The percentage (weighted mean) of patients with eradication success was calculated. Meta-analysis was performed combining the odds ratios (ORs) of the individual studies in a global OR.

RESULTS

The mean eradication rate with pantoprazole plus clarithromycin for 14 days was 60%. Cure rates with 7 day pantoprazole based triple regimens were higher: pantoprazole, amoxicillin and clarithromycin (78%); pantoprazole, clarithromycin and nitroimidazole (84%); and pantoprazole, amoxicillin and nitroimidazole (74%). Twelve studies comparing pantoprazole and other PPIs were selected for the meta-analysis, including 534 and 603 patients, respectively. The mean eradication rate for H. pylori using pantoprazole plus antibiotics was 83%, and 81% when other PPIs were used (OR = 1; 95% confidence interval (CI) from 0.61 to 1.64). When sub-analysis was performed, including only studies comparing pantoprazole with omeprazole, or pantoprazole with lansoprazole, differences were also statistically non-significant. The meta-analysis of the six studies prescribing equivalent doses of all PPIs demonstrated similar results with pantoprazole and with other PPIs (OR = 1.07; 95% CI from 0.71 to 1.62), the results being statistically homogeneous.

CONCLUSIONS

Pantoprazole achieves similar cure rates to those of omeprazole and lansoprazole when co-prescribed with antibiotics for the eradication of H. pylori infection.

Pantoprazole: an update of its pharmacological properties and therapeutic use in the management of acid-related disorders

Pantoprazole (Protonix) is an irreversible proton pump inhibitor (PPI) that reduces gastric acid secretion. In combination with two antimicrobial agents (most commonly metronidazole, clarithromycin or amoxicillin) for 6-14 days, pantoprazole 40 mg twice daily produced Helicobacter pylori eradication rates of 71-93.8% (intent-to-treat [ITT] or modified ITT analysis) in patients without known antibacterial resistance. Pantoprazole-containing triple therapy was at least as effective as omeprazole- and similar in efficacy to lansoprazole-containing triple therapy in large trials. In the treatment of moderate to severe gastro-oesophageal reflux disease (GORD), oral pantoprazole 40 mg/day was as effective as other PPIs (omeprazole, omeprazole multiple unit pellet system, lansoprazole and esomeprazole) and significantly more effective than histamine H(2)-antagonists. Pantoprazole 20 mg/day provided effective mucosal healing in patients with GORD and mild oesophagitis. Intravenous pantoprazole 40 mg/day can be used in patients who are unable to take oral medication. Oral pantoprazole 20-40 mg/day for up to 24 months prevented relapse in most patients with healed GORD. According to preliminary data, oral pantoprazole 20 or 40 mg/day was effective at healing and preventing non-steroidal anti-inflammatory drug (NSAID)-related ulcers, and intravenous pantoprazole was at least as effective as intravenous ranitidine in preventing ulcer rebleeding after endoscopic haemostasis. Oral or intravenous pantoprazole up to 240 mg/day maintained target acid output levels in most patients with hypersecretory conditions, including Zollinger-Ellison syndrome. Oral and intravenous pantoprazole appear to be well tolerated in patients with acid-related disorders in short- and long-term trials. Tolerability with oral pantoprazole was similar to that with other PPIs or histamine H(2)-antagonists in short-term trials. Formal drug interaction studies have not revealed any clinically significant interactions between pantoprazole and other agents. In conclusion, pantoprazole is an effective agent in the management of acid-related disorders. As a component of triple therapy for H. pylori eradication and as monotherapy for the healing of oesophagitis and maintenance of GORD, pantoprazole has shown similar efficacy to other PPIs and greater efficacy than histamine H(2)-antagonists. Limited data suggest that it is also effective in Zollinger-Ellison syndrome and in preventing ulcer rebleeding. Pantoprazole is well tolerated with minimal potential for drug interactions. The availability of pantoprazole as both oral and intravenous formulations provides flexibility when the oral route of administration is not appropriate. Thus, pantoprazole is a valuable alternative to other PPIs in the treatment of acid-related disorders.

Current role of acid suppressants in Helicobacter pylori eradication therapy

Helicobacter pylori induces chronic active gastritis that may progress to atrophy. Serious clinical consequences are peptic ulcer disease and gastric malignancies. Today, treatment of the infection is an appropriate option and is strongly recommended in various clinical situations. Although many antibiotics are effective against H. pylori in vitro, few substances are suitable for use in vivo. This is because H. pylori lives in a unique environment in which several factors may affect the pharmacokinetic and pharmacodynamic properties of the anti-microbial agents. One of the most important factors is gastric acidity. This article reviews the effects of acid suppression on H. pylori and the associated gastritis, the potential mechanisms by which anti-secretory drugs such as proton pump inhibitors might enhance the activity of anti-microbials in vivo, and the results of clinical trials supporting the current view that proton pump inhibitors are a mainstay in the treatment of this infection.

Inhibitory activities of lansoprazole against respiration in Helicobacter pylori

Lansoprazole and its derivative AG-1789 dose-dependently inhibited cellular respiration by an endogenous substrate and decreased the ATP level in Helicobacter pylori cells. The inhibitory action of lansoprazole and AG-1789 against respiration was specific to substrates such as pyruvate and alpha-ketoglutarate and similar to the inhibitory action of rotenone, which is an inhibitor for the mitochondrial respiratory chain. Growth inhibition by lansoprazole and AG-1789 as well as by rotenone was augmented at high oxygen concentrations under atmospheric conditions. Since the 50% inhibitory concentrations of these compounds for the respiration were close to their MICs for H. pylori growth, the growth inhibition might be due to respiratory inhibition by these compounds.

[Changes in ultra rapid urease test and histopathological examination for Helicobacter pylori by antisecretory drugs]

BACKGROUND

One of the major problems when evaluating dyspeptic patients at public hospitals is the large interval between the consultation and the endoscopy, leading to the prescription of antisecretory drugs, what can be responsible for false results on examinations.

AIM

To evaluate changes in ultrarapid urease test and histopathological examination for Helicobacter pylori by antisecretory drugs.

METHODS

In a prospective double-blind study, 50 patients with dyspeptic complaints and endoscopic diagnosis of peptic ulcer, erosive gastritis, esophagitis or duodenitis with a positive urease test, were randomized to a 7-day course of treatment with either omeprazole 20 mg or ranitidine 300 mg a day. Before and after treatment, two biopsy specimens each were obtained from the antrum and corpus and an ultrarapid urease test and a histopathological examination for Helicobacter pylori were performed.

RESULTS

There were no significant changes in the results of ultrarapid urease test and histopathological examination for Helicobacter pylori after treatment with ranitidine. With omeprazole, we observed a decrease in positive results in ultrarapid urease test and histopathological examination for Helicobacter pylori in the antrum, but not in the corpus.

CONCLUSION

Omeprazole, used for 7 days can lead to negative results in ultrarapid urease test and histopathological examination for Helicobacter pylori in the antrum, and should not be employed in patients before the endoscopy is performed.

A novel action of the proton pump inhibitor rabeprazole and its thioether derivative against the motility of Helicobacter pylori

The motility of Helicobacter pylori was maximum at 37 degrees C and at pH 6. A newly developed proton pump inhibitor, rabeprazole (RPZ), and its thioether derivative (RPZ-TH) markedly inhibited the motility of H. pylori. The concentrations of the drug necessary to inhibit 50% of the motility were 0.25, 16, 16, and >64 microgram/ml for RPZ-TH, RPZ, lansoprazole, and omeprazole, respectively. No such inhibitory effects were observed with H(2) blockers or anti-H. pylori agents. The motilities of Campylobacter jejuni and C. coli-but not those of Vibrio cholerae O1 and O139, Vibrio parahaemolyticus, Salmonella enterica serovar Typhimurium, and Proteus mirabilis-were also inhibited. Prolonged incubation with RPZ or RPZ-TH inhibited bacterial growth of only H. pylori, except for a turbid colony mutant. The results indicate that RPZ and RPZ-TH have a characteristic inhibitory effect against the motility of H. pylori (spiral-shaped bacteria), which is distinguished from that against bacterial growth.

Pantoprazole: a new proton pump inhibitor

OBJECTIVE

This paper reviews the pharmacology, clinical efficacy, and tolerability of pantoprazole in comparison with those of other available proton pump inhibitors (PPIs).

METHODS

Relevant English-language research and review articles were identified by database searches of MEDLINE, International Pharmaceutical Abstracts, and UnCover, and by examining the reference lists of the articles so identified. In selecting data for inclusion, the author gave preference to full-length articles published in peer-reviewed journals.

RESULTS

Like other PPIs, pantoprazole exerts its pharmacodynamic actions by binding to the proton pump (H+,K+ -adenosine triphosphatase) in the parietal cells, but, compared with other PPIs, its binding may be more specific for the proton pump. Pantoprazole is well absorbed when administered as an enteric-coated, delayed-release tablet, with an oral bioavailability of approximately 77%. It is hepatically metabolized via cytochrome P2C19 to hydroxypantoprazole, an inactive metabolite that subsequently undergoes sulfate conjugation. The elimination half-life ranges from 0.9 to 1.9 hours and is independent of dose. Pantoprazole has similar efficacy to other PPIs in the healing of gastric and duodenal ulcers, as well as erosive esophagitis, and as part of triple-drug regimens for the eradication of Helicobacter pylori from the gastric mucosa. It is well tolerated, with the most common adverse effects being headache, diarrhea, flatulence, and abdominal pain. In clinical studies, it has been shown to have no interactions with various other agents, including carbamazepine, cisapride, cyclosporine, digoxin, phenytoin, theophylline, and warfarin.

CONCLUSIONS

Pantoprazole appears to be as effective as other PPIs. Its low potential for drug interactions may give it an advantage in patients taking other drugs.

Direct and indirect methods of measuring Helicobacter pylori drug susceptibility in vitro

This article outlines a number of methods for the determination of inhibitory and bactericidal activity against H. pylori. Direct methods rely on the ability of bacteria to divide and multiply and ultimately form visible colonies after subjection to antibiotic treatment. Indirect methods rely on the measurement of metabolic activity as a viability marker and are much more rapid, especially taking into account the slow growth and fastidious nature of the organism. Inhibitory concentration measurement does not indicate the bactericidal ability of a drug; inhibition of growth does not necessarily correlate with cell death. Theoretical generation of viable but nonculturable bacteria could bring in to question the validity of direct measurements based on the colony forming ability of an organism posttreatment.

Helicobacter pylori infection, chronic gastritis, and proton pump inhibitors

The proton pump inhibitors (PPIs) omeprazole, lansoprazole, and pantoprazole are widely used as antisecretory drugs and, in association with antibiotics, for the treatment of Helicobacter pylori infections. PPIs possess antibacterial activity against H. pylori in vitro, and may also exert an anti-inflammatory effect by interfering with the cellular immune response to infection. Their antimicrobial activity is selective for H. pylori. Lansoprazole is the most effective, although its bactericidal activity is similar to that of omeprazole. Pantoprazole is the least effective. The mechanisms that account for the antibacterial effects of PPIs may depend on a structural similarity of PPIs to antibiotics which are active against H. pylori, on the inhibition of bacterial urease exerted by PPIs, or on the possible interaction of PPIs with bacterial ATPases that regulate the transmembrane ion flux. Recent studies have shown that PPIs have anti-inflammatory actions and can interfere with the host-bacteria interactions. Lansoprazole can bind to polymorphonuclear leukocytes that infiltrate the gastric mucosa colonized by H. pylori and can thus inhibit the oxidative burst of activated inflammatory cells. In an in vivo study, lansoprazole reduced the degree of activity of histologic gastritis independently of the presence of H. pylori. In another study, omeprazole was capable of inhibiting the cytotoxic activity of NK T cells. Investigation of PPI interactions with H. pylori activities and the cellular immune response to the infection may help us to understand the pathogenic mechanisms of H. pylori-associated diseases and enable clinicians to better treat them.

Proton pump inhibitors. Pharmacology and rationale for use in gastrointestinal disorders

Proton pump inhibitors (PPIs) are drugs which irreversibly inhibit proton pump (H+/K+ ATPase) function and are the most potent gastric acid-suppressing agents in clinical use. There is now a substantial body of evidence showing improved efficacy of PPIs over the histamine H2 receptor antagonists and other drugs in acid-related disorders. Omeprazole 20 mg/day, lansoprazole 30 mg/day, pantoprazole 40 mg/day or rabeprazole 20 mg/day for 2 to 4 weeks are more effective than standard doses of H2-receptor antagonists in healing duodenal and gastric ulcers. Patients with gastric ulcers should receive standard doses of PPIs as for duodenal ulcers but for a longer time period (4 to 8 weeks). There is no conclusive evidence to support the use of a particular PPI over another for either duodenal or gastric ulcer healing. For Helicobacter pylori-positive duodenal ulceration, a combination of a PPI and 2 antibacterials will eradicate H. pylori in over 90% of cases and significantly reduce ulcer recurrence. Patients with H. pylori-positive gastric ulcers should be managed similarly. PPIs also have efficacy advantages over ranitidine and misoprostol and are better tolerated than misoprostol in patients taking nonsteroidal anti-inflammatory drugs (NSAIDs). In endoscopically proven gastro-oesophageal reflux disease, standard daily doses of the PPIs are more effective than H2-receptor antagonists for healing, and patients should receive a 4 to 8 week course of treatment. For severe reflux, with ulceration and/or stricture formation, a higher dose regimen (omeprazole 40 mg, lansoprazole 60 mg, pantoprazole 80 mg or rabeprazole 40 mg daily) appears to yield better healing rates. There is little evidence that PPIs lead to resolution of Barrett's oesophagus or a reduction of subsequent adenocarcinoma development, but PPIs are indicated in healing of any associated ulceration. In Zollinger-Ellison syndrome, PPIs have become the treatment of choice for the management of gastric acid hypersecretion.

Short-term low-dose pantoprazole-based triple therapy for cure of Helicobacter pylori infection in duodenal ulcer patients

BACKGROUND

The eradication of Helicobacter pylori infection has been achieved using various therapy regimens, but the efficacy of the proton-pump inhibitor pantoprazole as part of these regimens has not yet been widely tested.

AIM

To evaluate the efficacy and tolerability of a 1-week low-dose pantoprazole-based triple therapy in patients with H. pylori-positive duodenal ulcer.

METHODS

In an open single-centre prospective study, 71 patients with endoscopically proven active duodenal ulcer and H. pylori infection received pantoprazole 40 mg o.m. for 4 weeks, and during the first week a combination antimicrobial treatment comprising tinidazole 500 mg b.d. plus clarithromycin 250 mg b.d. H. pylori eradication was defined as concordant negative histology and rapid urease test performed at endoscopy 4-6 weeks after the end of treatment, confirmed 4 weeks later by 13C-urea breath test.

RESULTS

Sixty-six patients (93%) completed the trial and five patients were lost to follow-up. H. pylori infection was cured in 61 out of the 66 patients who completed the trial (per-protocol analysis: 92.4%, 95% CI: 83.2-97.5%; intention-to-treat analysis: 85.9%, 95% CI: 75.7-93.0%). At final endoscopy, 65 out of 66 patients had healed ulcer (98.5%). Mild adverse events occurred in six patients (9.1%).

CONCLUSIONS

One-week low-dose pantoprazole-based triple therapy is a simple, effective and well-tolerated regimen for ulcer healing and H. pylori eradication in patients with duodenal ulcer.

Nizatidine in combination with amoxycillin and clarithromycin in the treatment of Helicobacter pylori infection

BACKGROUND

The efficacy of H2-antagonists in combination with antibiotics in curing Helicobacter pylori infection remains controversial, and it is uncertain whether double dose H2-antagonist therapy is superior to standard dose.

AIM

To determine the efficacy of two doses of nizatidine in combination with two antibiotics in the treatment of H. pylori.

METHODS

A randomized controlled trial was conducted in 160 patients comparing nizatidine 150 mg with 300 mg b.d. (standard vs. double dose), in combination with clarithromycin (500 mg) and amoxycillin (1000 mg) b.d. for 14 days, in Australia and Taiwan. Compliance was based on a clinical assessment and pill count. H. pylori status was determined by histology (antrum and corpus) and CLO-test.

RESULTS

Baseline clinical and endoscopic findings were similar in both arms of the study. Based on an intention-to-treat analysis, cure of H. pylori was achieved in 78% (95% CI: 70.4-85.4%) in the standard nizatidine dose arm and 70% (95% CI: 61.6-78.2%) in the double dose arm (P=0.2). Similar cure rates were observed in ulcer and non-ulcer patient groups. Compliance was excellent in the single and double dose arms (85 and 91%, respectively).

CONCLUSIONS

The combination of nizatidine in standard or double dose with clarithromycin and amoxycillin is similarly efficacious in curing H. pylori infection.

Growth inhibitory and bactericidal activities of lansoprazole compared with those of omeprazole and pantoprazole against Helicobacter pylori

BACKGROUND

Helicobacter pylori plays a role in the pathogenesis of both duodenal and gastric ulcers. The aim of this study was to evaluate the effect of the proton pump inhibitor (PPI), lansoprazole, commonly used in eradication regimens, on growth, bactericidal activity and morphology of H. pylori in vitro in comparison with other PPIs.

MATERIALS AND METHODS

Growth inhibitory activity of each of the PPIs was evaluated by determining minimum inhibitory concentrations using an agar dilution method. Bactericidal activity was determined by analysis of the viable cells in culture at various time points after incubation with different concentrations of the PPIs. Bacterial morphology was examined using scanning electron microscopy of fixed cells after exposure to the test substances. Urease activity in cell extracts of H. pylori that had been incubated with increasing concentrations of the PPIs was determined by colorimetry.

RESULTS

The growth inhibitory activity of lansoprazole was significantly more potent than that of omeprazole or pantoprazole (MIC90 6.25 vs. 25 and 100 micrograms/ml, respectively). Exposure of H. pylori to lansoprazole produced loss of viability and an aberrant bacterial morphology, which was more extensive than seen with omeprazole or pantoprazole. Lansoprazole dose dependently inhibited urease activity; its effectiveness was comparable with omeprazole but more potent than pantoprazole.

CONCLUSIONS

The mechanism of action that leads to loss of viability of H. pylori cells appears to differ between the three PPIs investigated; lansoprazole was the most potent of the three agents in terms of growth inhibition and disruption of bacterial morphology.

Basis for the selective antibacterial activity in vitro of proton pump inhibitors against Helicobacter spp

Proton pump inhibitors of the benzimidazole type exert a specific antibacterial activity against Helicobacter pylori in vitro. In the present study, the basis for this selectivity was investigated, and in particular, various factors affecting the in vitro antibacterial activity of sulfide analogs of benzimidazoles were studied. Upon preincubation of omeprazole for a period of up to 72 h in a buffer at pH 7, a product was formed that was bactericidal for H. pylori but had no effect on urease activity. Sulfide constitutes the main end product of degradation. The sulfide analog of omeprazole (H 168/22) exerted a bactericidal activity specifically against both resting (in buffer) and growing (in broth) Helicobacter spp., and time-kill in buffer at pH 5 was enhanced compared to that at pH 7. There was no or very low covalent binding of 3H-labeled H 168/22 to Helicobacter spp. or to other gram-negative and gram-positive bacteria. In the presence of fetal calf serum (FCS) under the same conditions, binding was only slightly lowered while the killing activity was markedly reduced, indicating a probably nonspecific interaction with proteins and/or protection of bacterial target(s) by FCS. Addition of H 168/22 (four times the minimum bactericidal concentration [MBC]) to exponentially growing H. pylori immediately stopped growth, and after an incubation period of 20 h viable counts were reduced by >7 log10. One-hour exposure of H. pylori to the drug followed by repeated washing retarded growth by about 2 h, indicating that the effect is reversible after short-term exposure. MICs and MBCs of various sulfide structures were lower than those obtained in broth after the addition of the corresponding sulfoxide. Thus, the MBC of the sulfide structure of omeprazole against 140 clinical isolates of H. pylori ranged from 8 to 32 microg/ml, compared to an MBC of omeprazole of 32 to 128 microg/ml. A similar potency was also recorded against other helicobacters. In conclusion, formation of sulfides of benzimidazoles in culture media is the reason for the selective antibacterial effect against H. pylori. The sulfides rapidly exerted a reversible antibacterial activity, which was specific against both resting and growing Helicobacter spp. without any covalent protein binding.

Efficacy and tolerability of a one-week triple therapy consisting of pantoprazole, clarithromycin and amoxycillin for cure of Helicobacter pylori infection in patients with duodenal ulcer

BACKGROUND

Previous studies have shown that one-week triple therapy consisting of omeprazole, clarithromycin and amoxycillin may cure Helicobacter pylori infection in the vast majority of patients. The present study was designed to test the hypothesis that a triple therapy with pantoprazole, clarithromycin and amoxycillin cures the infection in > or = 80% of duodenal ulcer patients infected with H. pylori.

METHODS

In an open two-centre study, 60 duodenal ulcer patients were treated with pantoprazole 40 mg b.d., clarithromycin 500 mg b.d. and amoxycillin 1 g b.d. for 1 week. During the second week patients received pantoprazole 40 mg once in the morning. We assessed H. pylori infection before treatment and 4 weeks after cessation of the study medication by a rapid urease test, histology after Warthin-Starry stain and a 13C-urea breath test.

RESULTS

Sixty patients (42 males, mean age 47.4 years) entered the trial. All patients were infected with H. pylori. One patient was withdrawn from the study because of allergy to penicillin and six patients were protocol violators. H. pylori infection was cured in 47 out of 53 patients who completed the trial according to the protocol (89%; 95% CI: 80-97%) and in 49 of 60 patients included in the trial (82%; 95% CI: 72-92%). Four weeks after the last administration of study drugs, 55 out of 60 ulcers had healed (92%). Twenty-nine patients reported 51 adverse events that were mostly mild to moderate.

CONCLUSIONS

One-week triple therapy consisting of pantoprazole, clarithromycin and amoxycillin is a simple and effective approach to the cure of H. pylori infection in patients with duodenal ulcer. In those patients who took the drugs as prescribed the H. pylori cure rate was 89%, with the lower 95% confidence limit being 80%.

A risk-benefit assessment of drugs used in the eradication of Helicobacter pylori infection

Helicobacter pylori is the cause of chronic active gastritis and predisposes to peptic ulcer disease (PUD). Furthermore, H. pylori is linked to the pathogenesis of gastric lymphoma and gastric cancer. However, treatment of this infection has proven difficult. In the last decade, many antimicrobial compounds have been studied extensively as monotherapy as well as in combination with bismuth or acid-suppressive drugs. The individual drugs and the most important eradication regimens are discussed with special regard to their risks. In the past, highly complex multidrug regimens, fear of adverse effects and frequent eradication failures have hampered the broad acceptance of H. pylori-eradication therapies. Recently, new 1-week, low-dose combination regimens of 2 antibacterials with a proton pump inhibitor have consistently achieved eradication rates of 90% and more with an acceptably low rate of adverse effects. One week's standard triple therapy [tripotassium dicitrato bismuthate (or bismuth salicylate plus metronidazole plus tetracycline or amoxicillin) has been shown to be highly effective and tolerated better in combination with a proton pump inhibitor. This regimen is, however, more complex and has more adverse effects. Therefore, it is not recommended as first-line therapy. Equipped with these therapies physicians can now be strongly encouraged to use H. pylori eradication as the therapy of choice for patients with PUD and even extend this treatment to other H. pylori-associated disease conditions.

Oxygen concentration influences proton pump inhibitor activity against Helicobacter pylori in vitro

Omeprazole and lansoprazole are proton pump inhibitors that have shown activity against Helicobacter pylori and other Helicobacter species when tested by agar dilution. Lansoprazole was more active against H. pylori than was omeprazole, and the activity was independent of urease production. Disk susceptibility tests and agar dilution MIC determinations were performed to investigate the effects of incubation under different sets of atmospheric conditions on H. pylori inhibition. Oxygen concentration was found to influence proton pump inhibitor activity in vitro, with higher concentrations leading to greater susceptibility. The method of testing is important in determining the anti-Helicobacter activity of proton pump inhibitors.

In vitro antibacterial activity of omeprazole and its selectivity for Helicobacter spp. are dependent on incubation conditions

Factors affecting the in vitro antibacterial activity of omeprazole were studied. Our data show that 3H-labeled omeprazole covalently bound to Helicobacter pylori and to other gram-negative and gram-positive bacteria. The compound was found to bind to a broad range of proteins in H. pylori, and at pH 5, binding was enhanced 15-fold compared with binding at pH 7. The bactericidal activity correlated to the degree of binding, and at pH 5, a pH at which omeprazole readily converts to the active sulfenamide form, beta-mercaptoethanol, a known scavenger of sulfenamide, and fetal calf serum, to which noncovalent protein binding of omeprazole is known to occur, reduced the level of binding and almost entirely abolished the bactericidal activity. At pH 7 the killing activities of omeprazole and structural analogs (e.g., proton pump inhibitors) were dependent on the time-dependent conversion (half-life) to the corresponding sulfenamide. The bactericidal activity exerted by the sulfenamide form at pH 5 was not specific for the genus Helicobacter. However, in brucella broth at pH 7 with 10% fetal calf serum, only Helicobacter spp. were susceptible to omeprazole, with MBCs in the range of 32 to 64 micrograms/ml, and MBCs for more stable proton pump inhibitors were higher. Wild-type H. pylori and its isogenic urease-deficient mutant were equally susceptible to omeprazole. Thus, the urease is not a lethal target for omeprazole action in H. pylori. In conclusion, the antibacterial activities of omeprazole and analogs are dependent on pH and the composition of the medium used. Thus, at a low pH in buffer, these compounds have a nonselective action, whereas in broth at neutral pH, the mechanism of action is selective for Helicobacter spp.

Pantoprazole. A review of its pharmacological properties and therapeutic use in acid-related disorders

Pantoprazole is an irreversible proton pump inhibitor which, at the therapeutic dose of 40mg, effectively reduces gastric acid secretion. In controlled clinical trials, pantoprazole (40mg once daily) has proved superior to ranitidine (300mg once daily or 150mg twice daily) and equivalent to omeprazole (20mg once daily) in the short term (< or = 8 weeks) treatment of acute peptic ulcer and reflux oesophagitis. Gastric and duodenal ulcer healing proceeded significantly faster with pantoprazole than with ranitidine, and at similar rates with pantoprazole and omeprazole. The time course of gastric ulcer pain relief was similar with pantoprazole, ranitidine and omeprazole, whereas duodenal ulcer pain was alleviated more rapidly with pantoprazole than ranitidine. Pantoprazole (40mg once daily) showed superior efficacy to famotidine (40mg once daily) in ulcer healing and pain relief after 2 weeks in patients with duodenal ulcer in a large multicentre nonblinded study. In mild to moderate acute reflux oesophagitis, significantly greater healing was obtained with pantoprazole than with ranitidine and famotidine, whereas similar healing rates were seen with pantoprazole and omeprazole. Pantoprazole showed a significant advantage over ranitidine in relieving symptoms of heartburn and acid regurgitation. Reflux symptoms were similarly alleviated by pantoprazole and omeprazole. Preliminary results indicate that triple therapy with pantoprazole, clarithromycin and either metronidazole or tinidazole is effective in the treatment of Helicobacter pylori-associated disease; however, these findings require confirmation in large well-controlled studies. Pantoprazole appears to be well tolerated during short term oral administration, with diarrhoea (1.5%), headache (1.3%), dizziness (0.7%), pruritus (0.5%) and skin rash (0.4%) representing the most frequent adverse events. The drug has lower affinity than omeprazole or lansoprazole for hepatic cytochrome P450 and shows no clinically relevant pharmacokinetic or pharmacodynamic interactions at therapeutic doses with a wide range of drug substrates for this isoenzyme system. In conclusion, pantoprazole is superior to ranitidine and as effective as omeprazole in the short term treatment of peptic ulcer and reflux oesophagitis, has shown efficacy when combined with antibacterial agents in H. pylori eradication, is apparently well tolerated and offers the potential advantage of minimal risk of drug interaction.

The chemotherapeutic effects of H+/K+ inhibitors on Helicobacter pylori infection

Helicobacter pylori's powerful urease enzyme is essential for colonisation and adaptation to the acid milieu of the stomach. Eradication of infection with "standard triple therapy" abolishes the chronic immunological and inflammatory responses to H. pylori and, thus, cures gastritis and peptic ulcer. In vitro, proton pump inhibitors (PPI) are active against H. pylori with minimum inhibitory concentrations that compare favourably with bismuth salts. PPIs are also potent urease inhibitors, but because PPIs are also active against urease-negative mutant Helicobacter spp., it is unlikely that urease inhibition alone accounts for their anti-H. pylori activity. Early reports suggested that omeprazole monotherapy was able to eradicate H. pylori. This has not been confirmed by more comprehensive studies, which have shown that treatment with omeprazole is associated with a shift of infection from the antrum to the corpus. The explanation for this observation is unclear, but does not appear to be due to bacterial overgrowth. Raising the intragastric pH with a PPI lowers the minimum inhibitory concentration of the many antimicrobials, while decreasing the acid storage pool increases the intramucosal concentration. Dual therapy (omeprazole with either amoxycillin or clarithromycin) is a more logical and highly effective alternative to standard triple therapy, with fewer side effects and better patient compliance. However, H. pylori eradication regimens based on a PPI and two antimicrobials will be the first-line treatment for H. pylori gastritis and peptic ulcer in the future.

Reduced amoxicillin uptake into human gastric mucosa when gastric juice pH is high

Amoxicillin when administered with gastric acid suppressors has been shown to be effective in eradication of Helicobacter pylori in 50 to 80% of subjects. The aim of this investigator-blind crossover study was to determine if gastric mucosal amoxicillin uptake was affected by increasing gastric juice pH. Fifteen male subjects (7 H. pylori positive and 8 H. pylori negative) were randomized to receive 150 mg of ranitidine twice a day, 300 mg of ranitidine twice a day, or no drug for 2 days prior to upper endoscopy. The last dose of ranitidine was given 60 min prior to upper endoscopy, and amoxicillin (500 mg) was given 30 min prior to upper endoscopy. The amoxicillin concentrations in mucosal biopsy samples, gastric juice, and serum were determined by a standard microbiological bioassay technique. Mean amoxicillin levels were greater in samples of antrum, fundus, and duodenum for volunteers who received no ranitidine than in those receiving 300 mg of ranitidine (P < 0.05) and those receiving 150 mg of ranitidine (P < 0.05 except for fundus). Amoxicillin levels in the antrum, fundus, and duodenum were negatively correlated with gastric juice pH (P < 0.005 for antrum; P < 0.001 for fundus and duodenum). There was no correlation between gastric juice pH and amoxicillin levels in either gastric juice or serum. The amoxicillin concentration in gastric juice was significantly higher with 300 mg of ranitidine than with no ranitidine (P < 0.05). Thus, lower gastric juice pH is associated with a higher rate of mucosal uptake of amoxicillin.

Eradication of Helicobacter pylori

Although there are numerous publications reporting eradication results, the general picture is confused by the bewildering multiplicity of treatment schedules employed by the various workers. The over-riding need now is for large scale trials, and more especially for direct comparisons of different treatment regimens in the same populations of patients. Such data are entirely absent from the literature at present. Standardization of definitions and of methodology pertaining to diagnosis of eradication, recording of side effects, measurement of compliance and determination of recurrence or of reinfection, is badly needed. As the definition of eradication remains arbitrary, it is important to include genome fingerprinting techniques in the long-term follow-up for recurrence, so that the question of reinfection versus recrudescence can be examined (Bell et al, 1993b; Xia et al, 1994). Because of the wide differences in the agents used in H. pylori eradication therapies, proper double-blinding of treatment trials remains a difficult problem. This can be dealt with to some extent by ensuring that the interpretation of tests for H. pylori eradication is performed by personnel unaware of the clinical details. Review of the existing data on eradication of H. pylori indicates that clinically useful results can be achieved in some 70 to 95% of patients, on an intention to treat basis. Compliance, side effects and resistance to metronidazole remain the limiting factors. Efficacy, freedom from side effects, simplicity and low cost will determine the success of any regimen in the future. At present, it is not possible to make firm recommendations in favour of one regimen over another, but it seems reasonable to forecast that dual therapies consisting of a PPI and an antibiotic will receive much attention. Preparations consisting of an H2RA associated with a bismuth compound, which are used together with an antibiotic are an interesting approach. Compliance should be as good as with a normal dual therapy and the eradication results look promising (Wyeth et al, 1994; Webb et al, 1994). The advantages of dual therapies that include a PPI lie in their simplicity, in not relying on imidazole for their anti-H. pylori effect but on the profound inhibition of acid output produced by the PPI. Thus PPI based dual therapy can probably evoke better compliance than the more complicated regimens. The use of PPIs has other advantages in addition to decreasing the MIC90 of the antibiotic combined with it. This is because administration of a powerful inhibitor of gastric acid secretion, such as a PPI, will aid the rapid healing of an ulcer crater and will rapidly relieve the symptoms of peptic ulceration. Gastrin releasing peptide-stimulated acid secretion is raised in duodenal ulcer patients to approximately sixfold over control levels according to El-Omar et al (1993b), and although it returns to normal following the eradication of H. pylori, this process takes time to become effective (El-Omar et al, 1993a). Suppression of acid output provides an immediate therapeutic shield, while the decrease in inflammation and acid output secondary to H. pylori eradication can be established. The most widespread resistance to antibiotics exhibited by H. pylori is with respect to imidazoles. The prevalence of metronidazole resistance is widespread in the emergent countries (Glupczynski et al, 1990), but it is also appreciable in the West, especially in women, who may have been given metronidazole in the treatment of pelvic infections (Rautelin et al, 1992; Banatvala et al, 1994). Moreover, H. pylori becomes resistant to metronidazole very easily and often as a result of treatment which includes an imidazole compound (Malfertheiner, 1993; Banatavala et al, 1994). On the other hand, H. pylori resistance to macrolides is not widespread and does not develop easily during their administration. It is difficult to forecast which antibiotic will be the most widely used agent

Partial characterization and effect of omeprazole on ATPase activity in Helicobacter pylori by using permeabilized cells

ATPase activity in permeabilized cells of Helicobacter pylori as well as those of Helicobacter felis and Campylobacter jejuni was analyzed. The ATPase activities in these cells were most susceptible to sodium azide, fluoroaluminate, and dicyclohexylcarbodiimide, which are typical inhibitors of F ATPases. Optimal values for maximal activity were found to be at approximately pH 6.4, 6.0, and 6.0 for C. jejuni, H. pylori, and H. felis, respectively. The substituted benzimidazole compounds omeprazole, lansoprazole, and Eisai 3810 were found to have no effect on the F ATPase activity of H. pylori at concentrations which are inhibitory for cell growth (MICs). In addition, an extracellular, vanadate-susceptible ATPase activity was detected in H. pylori, which was also relatively insusceptible to the benzimidazole compounds. Thus, the mechanism of killing mediated by omeprazole and related compounds in Helicobacter pylori does not appear to be due to diminished ATPase activity.

Antibacterial properties of lansoprazole alone and in combination with antimicrobial agents against Helicobacter pylori

The activities of various types of antiulcer agents against Helicobacter pylori strains were determined by an agar dilution method. Among the compounds tested, benzimidazole proton pump inhibitors were found to have significant activity against this organism. The activity of lansoprazole was fourfold more potent than that of omeprazole and bismuth subsalicylate, with MICs ranging from 1.56 to 25 micrograms/ml. Exposure of Helicobacter pylori to lansoprazole led to an extensive loss of viability as well as suppression of virulence factors such as motility, adhesiveness to epithelial cells and urease activity. The combination of lansoprazole with antimicrobial agents such as penicillins, cephalosporins, macrolides, tetracyclines, aminoglycosides, quinolones, metronidazole and bismuth subsalicylate generally had an additive effect on inhibition of Helicobacter pylori growth.

Double-blind trial of omeprazole and amoxicillin to cure Helicobacter pylori infection in patients with duodenal ulcers

BACKGROUND/AIMS

Anti-Helicobacter pylori treatment with combinations of omeprazole and amoxicillin is a promising treatment option. The aim of this study was to investigate whether a daily omeprazole dose of 120 mg combined with amoxicillin would cure H. pylori infection at a rate comparable with that achieved with "triple therapy."

METHODS

In a double-blind, randomized, controlled, and multicenter trial in Germany, 270 patients with an H. pylori-associated duodenal ulcer were treated with 40 mg omeprazole three times a day and 750 mg amoxicillin three times a day for the first 14 days (n = 139) followed by 20 mg omeprazole once daily until day 42 or with omeprazole plus 750 mg amoxicillin placebo three times a day for the same time period (n = 131).

RESULTS

Cure rates of H. pylori infection were 91% in the omeprazole plus amoxicillin group, 0% in the omeprazole plus placebo group, and 89% and 0%, respectively, performing an intention-to-treat analysis. Cure of H. pylori infection in patients pretreated with omeprazole was only 58% compared with 95% in patients who were not. The cumulative 12-month relapse rates were 11.3% and 44% in the treatment groups and 1.6% in H. pylori-negative and 49% in H. pylori-positive patients.

CONCLUSIONS

The combination of 120 mg omeprazole daily and 2.25 g amoxicillin daily with its H. pylori cure rate of around 90% is one of the best tolerated and most effective treatment regimens.

Triple therapy with ranitidine, clarithromycin, and metronidazole in the treatment of Helicobacter pylori

BACKGROUND

To determine whether a triple therapy regimen for the treatment of Helicobacter pylori infection, consisting of ranitidine 300 mg q.i.d., clarithromycin 500 mg t.i.d., and metronidazole 500 mg t.i.d. would provide a safe and effective treatment regimen, we performed an open prospective study in 20 consecutive patients with proven H. pylori-associated non-ulcer dyspepsia or peptic ulcer disease.

METHODS

The percentage of patients in whom eradication of H. pylori succeeded was determined. A semiquantitative assessment of histology was performed, and the results were analysed using Wilcoxon's matched-pairs ranks tests; side effects were noted and graded.

RESULTS

Eradication was achieved in 19 of 20 patients, i.e. in 95% (confidence interval 85-100%). Eradication of the bacterium led to a significant improvement in semiquantitative histology scores; active antral inflammation decreased from (mean +/- SEM) 1.84 +/- 0.19 to 0.21 +/- 0.16 (p = 0.0004) and chronic antral inflammation from 2.47 +/- 0.14 to 1.16 +/- 0.14 (p = 0.0002); active gastric body inflammation decreased from 0.95 +/- 0.19 to 0.00 +/- 0.00 (p = 0.0015) and chronic inflammation from 1.68 +/- 0.17 to 0.32 +/- 0.11 (p = 0.0007). Side effects occurred in 45% of patients, but in over half of these patients only mild side effects occurred. Severe side effects did not occur, none of the patients discontinued the triple therapy.

CONCLUSIONS

Triple therapy with ranitidine, clarithromycin, and metronidazole provides a safe and effective treatment of H. pylori infection, resulting in a high eradication rate, and in significant decrease in semiquantitative histology scores. Further prospective studies are warranted.

Omeprazole, bismuth and clarithromycin in the sequential treatment of Helicobacter pylori infection

AIMS

To assess the therapeutic potential of clarithromycin, a new macrolide with high anti-Helicobacter pylori activity, given with bismuth salts and omeprazole in different regimens aimed at simplifying the treatment of H. pylori-related gastritis.

METHODS

Eighty-eight patients with proven H. pylori infection and gastritis were treated with one of the following four regimens: omeprazole 40 mg/day for one week (group A, n = 14); omeprazole 40 mg/day for one week followed by clarithromycin 1 g/day for 2 weeks (group B, n = 26); omeprazole 40 mg/day for one week followed by tripotassium dicitrato bismuthate 480 mg/day and clarithromycin 1 g/day, both for two weeks (group C, n = 26); and tripotassium dicitrato bismuthate 480 mg/day and clarithromycin 1 g/day for two weeks (group D, n = 22). Presence of H. pylori, histology and electron microscopy were assessed at entry and four weeks after the end of each treatment.

RESULTS

Omeprazole alone had no effect on H. pylori status. The highest eradication rate was obtained in group C patients (81%), a proportion significantly greater than that observed in group B (50%, P < 0.03) or group D patients (55%, P < 0.05).

CONCLUSION

Sequential treatment may be a useful option in the treatment of H. pylori-related gastritis.

Review article: treatments that impact favourably upon the eradication of Helicobacter pylori and ulcer recurrence

Healing the gastroduodenal mucosa through Helicobacter pylori eradication leads to a dramatic reduction in gastroduodenal ulcer relapse. Eradication of H. pylori proves to be difficult. Although the organism is sensitive to many antibiotics in vitro, the in vivo eradicating efficacy is often disappointing. This overview summarizes the most commonly used currently-available eradication schemes and the consequences of successful eradication in peptic ulcer disease.

Omeprazole. An update of its pharmacology and therapeutic use in acid-related disorders

Omeprazole, a gastric acid pump inhibitor, dose-dependently controls gastric acid secretion: the drug has greater antisecretory activity than histamine H2-receptor antagonists. Omeprazole 20 to 40 mg/day is more effective than histamine H2-receptor antagonists in the short term treatment of duodenal ulcer, gastric ulcer and reflux oesophagitis. Available data suggest that omeprazole 10 to 40 mg/day is also more effective than ranitidine in the maintenance therapy of duodenal ulcer and reflux oesophagitis. The drug is also effective in patients with duodenal ulcer, gastric ulcer or reflux oesophagitis poorly responsive to histamine H2-receptor antagonists. The efficacy of omeprazole 20 mg/day appears to be similar to that of lansoprazole 30 mg/day in the short term treatment of duodenal ulcer, gastric ulcer and reflux oesophagitis. However, most available studies have been reported in abstract form only, and 2 of 3 studies in patients with duodenal ulcer have shown greater healing rates at 2 (but not 4) weeks with lansoprazole. Helicobacter pylori eradication decreases duodenal ulcer relapse rates and appears to be associated with improved duodenal ulcer healing rates. Evidence also suggests that H. pylori eradication is associated with reduced gastric ulcer relapse rates. Omeprazole monotherapy may suppress but does not eradicate H. pylori infection. Eradication rates with omeprazole 20 or 40 mg twice daily plus amoxicillin usually up to 2 g/day (3 g/day in a few studies) for 2 weeks appear to be similar to those of standard triple therapy (bismuth salt plus metronidazole, plus tetracycline or amoxicillin) or omeprazole plus clarithromycin, although eradication rates vary widely. Omeprazole plus amoxicillin appears to be better tolerated than triple therapy and represents a first-line treatment alternative in patients with H. pylori-associated peptic ulcer disease. Omeprazole plus amoxicillin plus metronidazole appears to be more effective than omeprazole plus amoxicillin in patients with metronidazole-sensitive H. pylori infection. Omeprazole remains a treatment of choice in patients with Zollinger-Ellison syndrome. The dosages should be adjusted according to individual response. However, relatively low dosages of 10 to 40 mg/day may be sufficient in some patients. The drug has also shown promise in the treatment of children with severe reflux oesophagitis, in patients with reflux oesophagitis and coexisting systemic sclerosis, and in the prevention of aspiration pneumonia. Evidence suggests that omeprazole is more effective than ranitidine in patients with nonsteroidal anti-inflammatory drug (NSAID)-induced gastric damage who continue to take NSAIDs, especially in patients with large gastric ulcers; however, completion of ongoing studies is required to verify this.(ABSTRACT TRUNCATED AT 400 WORDS)

Short report: omeprazole-tetracycline combinations are inadequate as therapy for Helicobacter pylori infection

BACKGROUND

Current triple antimicrobial therapies cure Helicobacter pylori infection in 60-90% of cases but are cumbersome. Addition of omeprazole to amoxycillin has been shown to enhance effectiveness when compared to amoxycillin alone.

METHOD

We studied omeprazole 20 mg t.d.s. plus tetracycline 500 mg q.d.s. for 14 days (OMP/TCN) and omeprazole 40 mg in the morning plus tetracycline 500 mg q.d.s. along with bismuth subsalicylate tablets 2 q.d.s. (OMP/TCN/BSS) for 14 days. Forty-four patients (19 OMP/TCN, 25 OMP/TCN/BSS) with H. pylori peptic ulcer disease were studied. H. pylori status was evaluated at least 4 weeks after ending antimicrobial therapy.

RESULTS

In the OMP/TCN group cure of H. pylori infection was achieved in 5/19 (26%). Adding bismuth to the regimen improved the results; 4 weeks after ending therapy cure of H. pylori infection was achieved in 12/25 (48%).

CONCLUSIONS

Neither regimen can be recommended for routine cure of H. pylori infection. Although one cannot predict which antimicrobial therapies will be enhanced by the addition of omeprazole, these data suggest that future studies should evaluate drugs whose effectiveness is compromised by low pH.

Influence of omeprazole on urease activity of Helicobacter pylori in vitro

The influence of omeprazole on urease activity of 13 Helicobacter pylori strains was assessed in vitro employing different inocula of the bacteria and various concentrations of omeprazole. Bacteria were grown in liquid culture supplemented with omeprazole for 48 h. Afterwards, bacterial numbers were assessed and urease activity was measured in a spectrophotometric assay. In 10 strains, omeprazole had no influence on urease activity at concentrations up to 8 mg/l; higher concentrations had a bacteriostatic effect. Three strains were more resistant to omeprazole: These showed a marked diminution of urease activity although bacterial numbers were only slightly reduced. Thus a possible inhibitory effect of omeprazole should be taken into account when urease of Helicobacter pylori is measured for diagnostic purposes.

Short report: treatment of Helicobacter pylori-associated duodenal ulcer with omeprazole plus antibiotics

Omeprazole heals most duodenal ulcers after 4 weeks of treatment but relapse is common. Eradication of Helicobacter pylori is associated with reduced rate of ulcer relapse. This study investigates the effect of omeprazole with antibiotics in H. pylori-associated duodenal ulceration. Forty-three patients with endoscopically proven duodenal ulcer and H. pylori entered this study. Treatment consisted of 20 mg omeprazole daily (four weeks) and seven days (first week) treatment with 400 mg metronidazole t.d.s. and 500 mg tetracycline t.d.s. Four weeks after completing the treatment, 81% (35/43) had a healed duodenal ulcer, and 58% (25/43) had H. pylori eradication. In those who healed, at one year 21 remained H. pylori-negative, 12 had persistent H. pylori infection and 2 had re-infection. The ulcer relapse rate at one year was 26%: of the 9 who relapsed, 6 had persistent infection, 2 were re-infected, and only 1 was H. pylori-negative. This combination therapy of antibiotics with omeprazole successfully eradicates Helicobacter pylori and has a lower ulcer relapse than omeprazole alone.

Short report: high-dose omeprazole and amoxycillin in the treatment of Helicobacter pylori-associated duodenal ulcer

Thirteen consecutive patients with active duodenal ulcer disease were assigned to a treatment schedule with high-dose omeprazole and amoxycillin. Duodenal ulcer was diagnosed endoscopically in all patients, at which time antral biopsies were taken for culture and histology. All were positive for Helicobacter pylori and histological gastritis. Treatment was for 2 weeks: 80 mg omeprazole daily plus 500 mg amoxycillin syrup t.d.s. in the first week, followed by 40 mg omeprazole daily in the second week. Repeat gastroscopy was performed 4 weeks after completion of treatment in all patients. Duodenal ulcer healing occurred in 4/13 patients. H. pylori eradication was achieved in 2/4 patients with healed ulcers and in 3/9 patients with persistent ulceration. This study suggests that a short period of treatment with high-dose omeprazole and amoxycillin achieves low rates of ulcer healing and H. pylori eradication.

Short report: a non-metronidazole triple therapy for eradication of Helicobacter pylori infection--tetracycline, amoxicillin, bismuth

Triple therapies using bismuth, metronidazole and tetracycline or amoxicillin were the first truly successful anti-H. pylori therapies. Metronidazole resistance has become an increasing problem that has severely limited the usefulness of the original triple therapy. Resistance to tetracycline or amoxicillin has not been reported and both are effective against H. pylori. We therefore tested a new triple therapy consisting of 500 mg tetracycline, 500 mg amoxicillin, and 2 tablets of bismuth subsalicylate each administered four times daily (with meals and at bedtime) for 14 days during treatment with ranitidine 300 mg daily. H. pylori eradication was defined as no evidence of H. pylori one or more months after stopping therapy. H. pylori status was evaluated by a combination of urea breath test and histology. Sixteen patients with H. pylori infection and active peptic ulcers were enrolled. The new triple therapy was successful in only 7 individuals (43%). Metronidazole appears to be critical for the effectiveness of the original triple therapy. An alternative to metronidazole will be required for a new successful triple therapy.

Short report: omeprazole plus antibiotic combinations for the eradication of metronidazole-resistant Helicobacter pylori

Twenty-eight Helicobacter pylori-positive patients with metronidazole-resistant isolates and 25 with metronidazole-sensitive isolates were treated for 14 days with 40 mg omeprazole nocte plus 500 mg amoxycillin t.d.s. Eradication of H. pylori, defined as absence of the organism one month after cessation of treatment, was assessed using the [14C]urea breath test. The eradication rate in patients with metronidazole-resistant isolates was 14/28 (50%) while that in patients was metronidazole-sensitive isolates was 12/25 (48%). In contrast to these encouraging eradication rates, very poor results were obtained with a 7-day course of omeprazole (40 mg nocte) in combination with erythromycin ethylsuccinate (500 mg q.d.s.) and tripotassium dicitrato bismuthate tablets (120 mg q.d.s.). The latter eradication rates were 3/20 (15%) in patients taking erythromycin tablets and 3/19 (16%) in those taking a liquid formulation of erythromycin. All treatment regimens were well tolerated and all patients completed the prescribed course of therapy.