Trends in prescribing volumes and costs of proton pump inhibitors in three outpatient specialties: a three-year retrospective study in a tertiary hospital in Thailand.

OBJECTIVES: The study determined a comparative three-year trend in prescribing volumes and costs of proton pump inhibitors in three outpatient specialties of a tertiary hospital. METHODS: Prescription data for three consecutive fiscal years (2016-2018) were extracted from a tertiary hospital electronic database, for the gastrointestinal, cardiovascular and orthopaedic outpatient specialties. The data collected were individual proton pump inhibitors, overall and individual prescribing volumes (capsule/tablet) and costs, stratified by specialty and fiscal year. KEY FINDINGS: Of the three specialties, the largest volume of proton pump inhibitor prescriptions, mostly for omeprazole, comes from the orthopaedic specialty (46%). In terms of prescribing costs, at the top is the cardiovascular specialty (45.75%). Lansoprazole, which is one of the proton pump inhibitors on in the national list of essential medicines, contributed most to the cost. Prescribing proton pump inhibitors that are not included in the national list of essential medicines were responsible for over 90% of the costs in the cardiovascular and gastrointestinal specialties. An escalating trend in prescribing varied proton pump inhibitors, that is, esomeprazole, lansoprazole, pantoprazole, dexlansoprazole and rabeprazole, all of which were not on the list of essential medicines, was evident in the latter. CONCLUSIONS: The highest volume of proton pump inhibitor prescribing-mostly of omeprazole, was issued by the orthopaedic specialty. The cardiovascular specialty was responsible for the largest amount of cost. The increases in the uses and costs of varying proton pump inhibitors which were outside the national list of essential medicines were notable in the gastrointestinal specialty.

Cytochrome P450 1A2 Messenger RNA is a More Reliable Marker than Cytochrome P450 1A2 Activity, Phenacetin O-Deethylation, for Assessment of Induction Potential of Drug-Metabolizing Enzymes Using HepaRG Cells.

BACKGROUND: The HepaRG cells have key drug metabolism functionalities comparable to those of primary human hepatocytes. Many studies have reported that this cell line can be used as a reliable in vitro model for human drug metabolism studies, including the assessment of cytochrome P450 (CYP) induction. OBJECTIVES: The objective of this study is to determine whether CYP mRNA level measurement is superior to the CYP enzyme activity measurement as a convenient high-throughput method for evaluating CYP induction potential using HepaRG cells. METHODS: QuantiGene Plex 2.0 Assay and LC/MS/MS. mRNA expression levels and enzyme activities of CYP1A2, CYP2B6, and CYP3A in HepaRG cells treated with prototypical inducers of each CYP isoform [omeprazole (OME) for CYP1A2, phenobarbital (PB) for CYP2B6, and rifampicin (RIF) for CYP3A] were evaluated. RESULTS: Although the activities of CYP2B6 and CYP3A were induced by treatment with PB and RIF, we found that the activity of phenacetin O-deethylase (PHOD), which is known as a marker of the activity of CYP1A2, was also enhanced by treatment with these non-CYP1A2 inducers in HepaRG cells. Based on previously published reports, we hypothesized that the expression ratio of CYP3A to CYP1A2 is much higher in HepaRG cells than in human hepatocytes; this may result in a nonnegligible contribution of CYP3A to the PHOD reaction in HepaRG cells. Studies using CYP3A inhibitor and pregnane X receptor-knockout HepaRG cells supported this hypothesis. CONCLUSION: The measurement of mRNA serves as a higher reliable indicator for the evaluation of CYP induction potential when using HepaRG cells.

Cognitive impact after short-term exposure to different proton pump inhibitors: assessment using CANTAB software.

INTRODUCTION: Studies have shown that proton pump inhibitors (PPIs) increase the brain burden of amyloid-beta (Aß) and also create vitamin B12 deficiency. However, these two phenomena have deleterious effect on cognition and Alzheimer's disease (AD). Since the use of PPIs has increased tremendously for the last few years, it is of great public health importance to investigate the cognitive impact of PPIs. Hence, the purpose of this study was to investigate the degree of neuropsychological association of each PPI with different cognitive functions. METHODS: Sixty volunteers of either gender were recruited and divided randomly into six groups: five test groups for five classes of PPIs and one control group. All the groups participated in the five computerized neuropsychological tests (nine subtests) of the Cambridge Neuropsychological Test Automated Battery twice: at the beginning of the study and 7 days thereafter. RESULTS: We found statistically and clinically significant impairment in visual memory, attention, executive function, and working and planning function. One-way analysis of variance findings showed that all PPIs had a similar negative impact on cognition. However, paired-samples t tests indicated that omeprazole showed significant (p < 0.05) results in seven subtests; lansoprazole and pantoprazole showed significant results in five subtests; and rabeprazole showed significant results in four subtests. Among five classes of PPIs, esomeprazole showed comparatively less impact on cognitive function with significant results in three subtests. CONCLUSIONS: The present study reveals for the first time that different PPIs have varying degrees of influence on different cognitive domains and have associations with AD. These findings should be considered when balancing the risks and benefits of prescribing these medications. A study done for a longer period of time with a larger sample size might yield better results.

Usefulness of antimicrobial susceptibility in the eradication of Helicobacter pylori.

The rate of eradication of Helicobacter pylori with standard triple therapy using omeprazole, amoxicillin and clarithromycin (OAC) is unacceptable in populations with high rates of clarithromycin resistance (15-20%). The aim of this study was to compare the efficacy of 10-day OAC therapy as the first-line treatment in patients diagnosed by culture with antimicrobial susceptibility or diagnosed by a (13) C-labelled urea breath test (UBT) without antimicrobial susceptibility in an area where the clarithromycin resistance rate was 15-20%. This was a retrospective cohort study of 266 patients, recruited consecutively throughout 2008. A total of 247 H. pylori-infected patients received antibiotic therapy (221 received the 10-day OAC therapy and 26 received other regimens) of which 134 patients were diagnosed by culture of gastric samples followed by antimicrobial susceptibility testing and 113 were diagnosed by UBT. In all patients, the eradication of H. pylori was checked by UBT. The cost of eradication by 10-day OAC treatment was assessed in each patient. The success rate of 10-day OAC therapy in patients diagnosed by culture and by UBT was 88% (103/117) and 49% (51/104), respectively (p <0.0005). The treatment was also more cost-effective in the former of these two groups (€571 versus €666). To perform culture and antimicrobial susceptibility of the H. pylori isolates was a more successful and cost effective strategy than empirical 10-day OAC treatment in populations with high rates of resistance to clarithromycin.

Novel stably transfected gene reporter human hepatoma cell line for assessment of aryl hydrocarbon receptor transcriptional activity: construction and characterization.

We constructed stably transfected gene reporter cell line AZ-AHR, allowing measurement of aryl hydrocarbon receptor (AhR) transcriptional activity. Human hepatoma HepG2 cells were transfected with a construct containing several AhR binding sites upstream of luciferase reporter gene. We prepared 12 clones and we characterized the best five in responsiveness to TCDD. Dose-response analyses were performed for various AhR ligands, including TCDD, 3-methylcholanthrene, indirubin, resveratrol, omeprazole, and SP600125. The EC(50) values were similar in all tested clones. Induction of luciferase was time-dependent, and treatment for 6 h with 5 nM TCDD was sufficient to evaluate AhR transcriptional activity in 96-well plate format (8-24 fold induction). Response to AhR ligands of cryopreserved cells after thawing was not significantly different from that of fresh cells. Cell line remained fully responsive to AhR ligands over 15 passages and 30 days in culture without significant alterations. Overall, we have developed novel human luciferase reporter cell line AZ-AHR for monitoring AhR transcriptional activity. The sensitivity of the assay allows high throughput format (96-well plate) and evaluation of luciferase activity as soon as after 6 h of incubation, which has potential implication for studies of cytotoxic compounds.

Assessment of a novel ß2-adrenoceptor agonist, trantinterol, for interference with human liver cytochrome P450 enzymes activities.

The effect of a novel ß(2)-adrenoceptor agonist, trantinterol on the activities of cytochrome P450 (CYP450) was investigated with human liver microsomes and human cryohepatocytes in order to assess the potential for drug-drug interactions. The ability of trantinterol to inhibit CYP450 activities was evaluated in vitro in human liver microsomes. Trantinterol did not inhibit CYP2C19, CYP2D6, and CYP3A4/5 (IC(50)>100 µM). It acted as a weak inhibitor of CYP1A2 and CYP2C9 with IC(50) of 70.8 and 81.9 µM, respectively. No time-dependent inhibitions were observed in the present research. To evaluate CYP450 induction, human cryohepatocytes (n=3) were used and treated once daily for 3 days with trantinterol (0.01, 0.1, and 1 ng/ml), after which CYP450 activities were measured. At concentration of 0.01 ng/ml, which is close to the C(max) at maximal recommended doses (50 µg), trantinterol was about 8% as effective as omeprazole (CYP1A2 inducer) only with donor 2. At concentration of 1 ng/ml, trantinterol was about 3.6 ± 3.1% as effective as rifampin (CYP3A4/5 inducer). These in vitro results indicated that, at pharmacological relevant concentrations, trantinterol will not produce clinically significant CYP450 inhibition or induction.

Sensitivity and proportionality assessment of metabolites from microdose to high dose in rats using LC-MS/MS.

BACKGROUND: The objective of this study was to evaluate the sensitivity requirement for LC-MS/MS as an analytical tool to characterize metabolites in plasma and urine at microdoses in rats and to investigate proportionality of metabolite exposure from a microdose of 1.67 µg/kg to a high dose of 5000 µg/kg for atorvastatin, ofloxacin, omeprazole and tamoxifen. RESULTS: Only the glucuronide metabolite of ofloxacin, the hydroxylation metabolite of omeprazole and the hydration metabolite of tamoxifen were characterized in rat plasma at microdose by LC-MS/MS. The exposure of detected metabolites of omeprazole and tamoxifen appeared to increase in a nonproportional manner with increasing doses. Exposure of ortho- and para-hydroxyatorvastatin, but not atorvastatin and lactone, increased proportionally with increasing doses. CONCLUSION: LC-MS/MS has demonstrated its usefulness for detecting and characterizing the major metabolites in plasma and urine at microdosing levels in rats. The exposure of metabolites at microdose could not simply be used to predict their exposure at higher doses.

Follow-up to the pre-validation of a harmonised protocol for assessment of CYP induction responses in freshly isolated and cryopreserved human hepatocytes with respect to culture format, treatment, positive reference inducers and incubation conditions.

We have compared induction responses of human hepatocytes to known inducers of CYP1A2, CYP2B6, CYP2C and CYP3A4/5 to determine whether the culture format, treatment regimen and/or substrate incubation conditions affected the outcome. CYP induction responses to prototypical inducers were equivalent regardless of pre-culture time (24h or 48h), plate format (60mm or 24-well plates) used or whether CYP activities were measured in microsomes or whole cell monolayers. Fold-induction of CYP3A4/5 by 1000muM PB and 10microM RIF were equivalent. In contrast, the fold-induction of CYP2B6 by PB was 3-fold higher that by 10microM RIF. In addition to inducing CYP1A2, 50microM OME also induced CYP3A4/5 in 50% of the donors tested. CYP2B6 was induced in 14 out of 21 donors by BNF; however CYP3A4/5 was unaffected by BNF in these donors. In order to confirm that donor-to-donor variation was not due to inter-laboratory differences, the induction responses of 5 different batches of cryopreserved human hepatocytes were compared in two different laboratories. The induction of CYP1A2, CYP2B6 and CYP3A4 measured in our laboratory were equivalent to those obtained by the commercial companies, proving good between-laboratory reproducibility. In conclusion, there is some flexibility in the treatment and incubation protocols for classical CYP induction assays on human hepatocytes. Both RIF and PB are suitable positive control inducers of CYP3A4/5 but PB may be more appropriate for CYP2B6 induction. BNF may be more appropriate for CYP1A2 induction than OME since, in contrast to the latter, it does not induce CYP3A4. Induction responses using hepatocytes from the same donor but in different labs can be expected to be similar. The good reproducibility of induction responses between laboratories using cryopreserved hepatocytes underlines the usefulness of these cells for these types of studies.

Experimental model in the qualitative and quantitative assessment of non-Helicobacter gastric microflora under proton pump inhibitors action.

PURPOSE: To evaluate models of gastric material collection from Wistar rats with and without using proton pump inhibitors(PPIs). METHODS: Twenty-four rats underwent intraperitoneal omeprazol treatment, and other 12 received similar treatment with 0.9% saline. All animals underwent collection of gastric material samples, after stomach removal, by either biopsies, or aspirates, or swabs. Samples were bacteriologically processed in order to identify species and strains. Values are described as natural logarithm of colony former units per mL [Ln(CFU/mL)]. Kruskal-Wallis and Mann-Whitney non-parametric tests were used, and p<0.05 was set as statistically significant. RESULTS: Significant difference was not seen for Ln (UFC/mL) values among the three methods of collection irrespective of using or not omeprazol. Also, significant difference was not seen in Ln (UFC/mL) values when comparing a method with each others, either using omeprazol or placebo. A significant increase of bacteria strains occurred when PPI was used, and this was seen on the three ways of collection, mainly in biopsy and swab. CONCLUSION: No difference occurred among the three methods of collecting bacteria samples from stomachs of rats, either when using placebo or omeprazol. A remarkable change is seen on animals bacterial microflora when PPIs are used, and bacteria are better identified when swab and biopsy are used.

A simultaneous assessment of CYP3A4 metabolism and induction in the DPX-2 cell line.

The DPX-2 cell line, a derivative of HepG2 cells, harbors human PXR and a luciferase-linked CYP3A4 promoter. These cells were used in a panel of cell-based assays for a parallel assessment of CYP3A4 induction, metabolism, and inhibition at the cellular level. CYP3A4 induction in the DPX-2 cell line by various agents was monitored in 96-well plates by a luciferase-based transcriptional activation assay. Of the prototypical CYP3A4 inducers examined, all exhibited elevated luciferase activity in DPX-2 cells. CYP3A4 enzyme activity in noninduced and rifampicin-induced DPX-2 cells was also assessed using Vivid fluorogenic substrates. Significantly elevated CYP3A4 activity levels (2.8-fold +/- 0.2-fold above DMSO-treated cells) were found in DPX-2 cells after 48 hours of exposure to rifampicin, but were undetectable in parental HepG2 cells. Rifampicin-induced activity levels were found to be suitable for assessing the inhibitory potential of new chemical entities in downstream CYP3A4 inhibition assays. The elevated CYP3A4 activity was inhibited 85% by 10 microM ketoconazole. In addition, a cytotoxicity assay to correct for possible toxic effects of compounds at the cellular level was applied. The comparative data obtained with a combination of the above assays suggests that the application of several independent in vitro technologies used in DPX-2 cells is the best possible strategy for the assessment of the complex phenomena of CYP3A4 induction and inhibition.

Comparison of two management strategies for Helicobacter pylori treatment: clinical study and cost-effectiveness analysis.

BACKGROUND: First-line proton pump inhibitor-based triple and quadruple therapies for Helicobacter pylori eradication present similar levels of efficacy. Cross-over treatment (quadruple following triple failure, and triple following quadruple failure) seems the most sensible approach to treatment failures, but the two strategies -'quadruple first' versus 'triple first'- have not been previously compared. The aims of our study were to assess the usefulness and the cost-effectiveness of the two treatment strategies. MATERIAL AND METHODS: Forty-nine out of 344 patients included in a previous study comparing triple therapy - 7 days of omeprazole, amoxicillin and clarithromycin twice a day - with quadruple therapy - 7 days of omeprazole twice a day, plus tetracycline, metronidazole and bismuth subcitrate three times a day - failed initial treatment and were assigned to cross-over therapy. Cure was determined by urea breath test. A decision analysis was performed to compare the two eradication strategies. RESULTS: Intention to treat cure rates were 46% (10/22 patients; 95% CI 24-68%) for second-line triple therapy and 63% (17/27 patients; 95% CI 42-81%) for second-line quadruple therapy. Per protocol cure rates were 71% and 85%, respectively. Intention to treat cure rates were 87% (95% CI 81-92%) for the 'triple first' versus 86% (95% CI 80-91%) for the 'quadruple first' strategy (p = .87). The 'quadruple first' strategy was more cost-effective. The incremental cost of 'triple first' strategy per person was 19 in the low-cost area and 65 US dollars in the high-cost area. CONCLUSIONS: The effectiveness of 'triple first' and 'quadruple first' strategies is similar, although the latter seems slightly more cost-effective.

[Pharma clinics medication of the month. Esomeprazole]. / Pharma clinics le médicament du mois. L'ésoméprazole.

Esomeprazole is the last PPI registered on the Belgian market. It is the stable s-isomer of omeprazole. It has a better pharmacokinetic profile than omeprazole (racemate), allowing also better clinical performances. Esomeprazole is the first PPI shown superior to omeprazole in acute and chronic treatment of gastro-esophageal reflux disease. Controlled trials with this drug have also allowed to define new cost-effective strategies, such as on demand treatment for endoscopy-negative gastro-esophageal reflux and one week treatment of Helicobacter pylori positive duodenal ulcer.

Esomeprazole: a clinical review.

The pharmacology, pharmacodynamics, pharmacokinetics, clinical efficacy, and adverse effects of esomeprazole are reviewed. Esomeprazole, a proton-pump inhibitor (PPI), is the S-isomer of omeprazole. Esomeprazole has FDA-approved labeling for use in the treatment of symptomatic gastroesophageal reflux disease (GERD), including healing and maintenance of healing of erosive esophagitis and as part of a triple-drug regimen for Helicobocter pylori infection. Esomeprazole is structurally similar to other PPIs but is the first PPI to include only the active isomer, which may lead to improved pharmacokinetic and pharmacodynamic characteristics. Esomeprazole maintains intragastric pH at a higher level and above 4 for a longer period than other PPIs. Clinical studies have shown that esomeprazole is at least equivalent in safety and efficacy to other drugs in the class. Esomeprazole has demonstrated efficacy in the treatment of erosive esophagitis, the maintenance of healing of erosive esophagitis, and the treatment of signs and symptoms of GERD. Effective dosages are 20 or 40 mg orally every day or as needed. Esomeprazole magnesium 40 mg once daily in combination with amoxicillin and clarithromycin is effective in eradicating H. pylori infection. The potential for interacting with other drugs is limited and is similar to that of omeprazole. The most common adverse effects are headache, respiratory infection, and abdominal symptoms. Esomeprazole has pharmacokinetic properties that may make it more effective than omeprazole in some patients.

Low-dose lansoprazole and clarithromycin plus metronidazole vs. full-dose lansoprazole and clarithromycin plus amoxicillin for eradication of Helicobacter pylori infection.

AIM: To compare, in a randomized controlled trial, the efficacy and tolerability of two 1-week triple therapies for Helicobacter pylori eradication. METHODS: One hundred and thirty-four consecutive patients with non-ulcer dyspepsia and H. pylori infection were randomized to receive lansoprazole 30 mg once daily, clarithromycin 250 mg twice daily, and metronidazole 500 mg twice daily (LCM group), or lansoprazole 30 mg twice daily, clarithromycin 500 mg twice daily, and amoxicillin 1000 mg twice daily (LCA group). H. pylori status was assessed by rapid urease test, histology and 13C-urea breath test before and after therapy. RESULTS: At 3 months, H. pylori eradication (intention- to-treat/per protocol analysis) was 92.4%/93.8% in the LCM group and 83.1%/85.7% in the LCA group (P=N.S.). Side-effects were more frequently reported in the LCA group (37.9%) than in the LCM group (19.7%) (P < 0.05). CONCLUSIONS: In this open, randomized controlled trial, eradication of H. pylori by low-dose lansoprazole and clarithromycin plus metronidazole was higher with significantly less side-effects than by full-dose lansoprazole and clarithromycin plus amoxicillin. This finding may be related to the stronger synergism of clarithromycin plus metronidazole, even at lower doses, than of clarithromycin plus amoxicillin. Considering the lower cost as well, LCM should be preferred to LCA in the eradication of H. pylori.

Life cycle of a block buster drug: discovery and development of omeprazole (Prilosec).

Block buster drugs share a variety of common features, among which is the tendency to create entirely new markets. For example, an early "informed" estimate of the potential market size for the hypothetically "perfect" peptic ulcer drug was thirty-five million dollars. Based on current sales, however, we reckon this hypothesis to have underestimated the actual market demand for omeprazole (Prilosec) by about 400-fold. Similarly, prior to the introduction of the "retired" block busters chlordiazepoxide and diazepam (Librium and Valium), the market for "minor tranquilizers" in the treatment of anxiety and neurosis did not exist. Thus, once an emerging block buster seems to be therapeutically working, it is not unusual for diagnostic rates of the disease for which it is indicated and efficacious to actually increase. Top block buster drugs generally have or appear to have a high margin of safety.

Quantitative assessment of gastric corpus atrophy in subjects using omeprazole: a randomized follow-up study.

OBJECTIVES: Atrophy of the gastric mucosa most frequently results from chronic Helicobacter pylori infection and is a risk factor for the development of gastric cancer. Profound acid suppression has been suggested to accelerate the onset of gastric mucosal atrophy. The aim of the present study was to evaluate the effects of H. pylori eradication and acid inhibition by omeprazole on gastric atrophy by means of quantitative analysis of tissue morphology. METHODS: Corpus biopsy specimens were obtained during endoscopy in 71 gastroesophageal reflux disease (GERD) patients at baseline and after 3 and 12 months. A total of 48 subjects were H. pylori positive and 23 were H. pylori negative. All subjects received omeprazole 40 mg once daily after the first endoscopy for 12 months. After randomization, 27 of the 48 H. pylori-positive patients also received eradication therapy. In hematoxylin and eosin-stained slides the volume percentages of glands (VPGL), volume percentages of stroma (VPS), and volume percentages of infiltrate (VPI) were measured in the glandular zone of the mucosa. The results were evaluated by computerized morphometric analysis. RESULTS: In the eradication group, the mean VPGL increased from 63.0% to 67.7% and 71.5% after 3 and 12 months (p < 0.001), respectively. The mean VPS and VPI decreased from 33.1% and 4.0% to 29.3% and 3.0% and to 26.4% and 2.1% (p < 0.001 and p = 0.04), respectively. Patients with the lowest VPGL at baseline showed the largest increases of VPGL after eradication treatment as compared to patients with high a VPGL at baseline. In the H. pylori-persistent group the VPI showed a significant increase (p = 0.01), and in the H. pylori-negative group VPGL increased significantly from 71.9% to 75.2% (p = 0.03) after 12 months. CONCLUSIONS: Eradication of H. pylori leads to restitution of the volume percentage of glandular epithelium to normal levels, even during treatment with proton pump inhibitors. Whether this effect can also be seen in patients with marked atrophy needs further investigation.

Lack of interaction between lansoprazole and propranolol, a pharmacokinetic and safety assessment.

Due to the prevalence of both gastrointestinal and cardiovascular diseases, it is likely that patients may be coprescribed gastric parietal cell proton pump inhibitors and beta-adrenergic antagonists. Therefore, the objectives of this phase I study were to assess the potential effects of the coadministration of lansoprazole on the pharmacokinetics of propranolol and to evaluate the safety of propranolol with concomitant lansoprazole dosing. In a double-blind fashion, 18 healthy male nonsmokers were initially randomized to receive either 60 mg oral lansoprazole, each morning for 7 days, or an identical placebo (period 1). On day 7, all subjects were concomitantly administered oral propranolol, 80 mg. After a minimum of 1 week following the last dose of either lansoprazole or placebo, subjects were crossed over to the opposite treatment for another 7 days (period 2). Subjects were again administered oral propranolol on day 7. During both treatment periods, blood samples for the determination of plasma propranolol and 4-hydroxy-propranolol were obtained just before the dose and at 0.5, 1, 2, 3, 4, 6, 8 12, 16, 20, and 24 hours postdose. Plasma propranolol and 4-hydroxy-propranolol concentrations were determined by using HPLC with fluorescence detection. The Cmax, tmax, AUC0-infinity, and t1/2 values for propranolol, as well as the AUC0-infinity for 4-hydroxy-propranolol, were calculated and compared between the lansoprazole and placebo regimens. The mean age of the 15 subjects who successfully completed the study was 31 years (range: 24-38 years), and their average weight was 174.8 pounds (range: 145-203 pounds). There were no statistically significant differences between the lansoprazole and placebo regimens for the propranolol Cmax, tmax, AUC0-infinity, and t1/2 values. Also, there were no statistically significant differences between regimens for the 4-OH-propranolol AUC0-infinity. Safety evaluations, which included adverse events, vital signs, clinical laboratory determinations, ECG, and physical examinations, revealed no unexpected clinically significant findings and did not suggest a drug-drug interaction. In conclusion, lansoprazole does not significantly alter the pharmacokinetics of propranolol, suggesting that it does not interact with the CYP2D6- or CYP2C19-mediated metabolism of propranolol. Modification of a propranolol dosage regimen in the presence of lansoprazole is not indicated, based on the pharmacokinetic analysis and the lack of a clinically significant alteration in the pharmacodynamic response.

Noninvasive assessment of gastric acid secretion in man. Application of electrical impedance tomography (EIT).

Electrical impedance tomography (EIT) is a tubeless technique that generates tomographic images of gastric resistivity. We investigated the application of EIT to measure gastric acid secretion. Nineteen normal subjects underwent a standard intubation test. Basal acid output (BAO) and stimulated acid output (SAO) (millimoles per hour) were measured before and after pentagastrin, respectively. On a different day, EIT was performed before (basal) and after pentagastrin (stimulated). The changes in impedance over time were measured and the area under the curve (AUC) was calculated. Both the tests were repeated in 13 subjects after omeprazole treatment. As in the intubation test, there was the expected increase in AUC value after pentagastrin (basal vs stimulated; 1.2 +/- 2.8 vs 731 +/- 297, P < 0.0001). A significant fall in acid output and AUC following omeprazole pretreatment was observed (without vs with omeprazole; 20.5 +/- 5.7 vs 0.03 +/- 0.06, P < 0.0001 for intubation test and 731 +/- 297 vs 44 +/- 172, P < 0.0001 for EIT). There was a significant correlation between SAO and the delta AUC with (r = 0.65 P < 0.001) or without (r = 0.95, P < 0.001) omeprazole and in all the experiments (r = 0.87, P < 0.001). This study demonstrates the predictable change of gastric impedance and may be useful as a noninvasive test for measuring gastric acid secretion.

Pharmacological therapy of Helicobacter pylori infection.

Helicobacter pylori has been associated with several diseases including peptic ulcer disease and gastric cancer. Eradication of H pylori not only results in ulcer healing, but reduces recurrences essentially curing peptic ulcer disease. Eradicating H pylori can be difficult. There are several reasons for antimicrobial failure, and the resistance rates for several antibiotics are increasing. The most common drugs used to treat this infection include amoxicillin, clarithromycin, tetracycline, bismuth, and omeprazole and lansoprazole. Dual therapy using a proton pump inhibitor and a single antibiotic gives a suboptimal eradication rate. Triple therapy using at least two antibiotics and either bismuth or a proton pump inhibitor gives satisfactory eradication rates of 90%. However, these regimens are complicated and have significant side effects and compliance problems. The ideal regimen has yet to be developed. In the future, we will prevent infection with immunization. Several vaccines are being developed.

Time of Helicobacter pylori eradication assessment following treatment.

BACKGROUND: The most appropriate time to assess accurately Helicobacter pylori eradication following treatment has been debated, with recommendations ranging from 1 to 3 months. The purpose of this study was to validate the assessment of H. pylori eradication 1 month following treatment. MATERIALS AND METHODS: Three randomized, double-blind, active-controlled clinical trials were conducted in patients with endoscopically verified, active duodenal ulcers and H. pylori infection. Patients were treated with various treatment regimens of omeprazole plus amoxicillin. Ulcer healing, H. pylori eradication, and ulcer relapse were examined. Patients underwent repeat endoscopy and biopsy at 1 and 6 months following treatment (or sooner if symptoms returned) to determine the recurrence of ulcers and H. pylori status. To determine the accuracy of measuring H. pylori eradication at 1 month posttreatment, we compared the H. pylori status at 1 month and 6 months following treatment. RESULTS: In a combination of treatment groups and studies, a total of 384 evaluable patients represented data at both time points and were included in the analysis. Of those eradicated at 1 month posttreatment, 94% (141 of 150) remained eradicated at 6 months posttreatment. The proportion of patients with H. pylori eradicated at 1 month posttreatment did not differ significantly from that at 6 months posttreatment for each study. The overall efficiency of the two tests (agreement between tests) was 93% (359 of 384). Agreement between the 1-month and 6-month posttreatment H. pylori assessment was apparent, regardless of the treatment used. CONCLUSION: H. pylori eradication measured 1 month following cessation of treatment accurately reflects successful treatment of the infection.