Evaluation of the pharmacokinetics and pharmacodynamics of intravenous lansoprazole

Microbial inulinase promotes fructan hydrolysis under simulated gastric conditions

Fermentable oligo-, di-, monosaccharides and polyols (FODMAPs) have emerged as key contributors to digestive discomfort and intolerance to certain vegetables, fruits, and plant-based foods. Although strategies exist to minimize FODMAP consumption and exposure, exogenous enzyme supplementation targeting the fructan-type FODMAPs has been underexploited. The objective of this study was to test the hydrolytic efficacy of a food-grade, non-genetically engineered microbial inulinase preparation toward inulin-type fructans in the INFOGEST in vitro static simulation of gastrointestinal (GI) digestion. Purified inulin was shown to undergo acid-mediated hydrolysis at high gastric acidity as well as predominantly inulinase-mediated hydrolysis at lower gastric acidity. Inulinase dose-response simulations of inulin, garlic, and high-fructan meal digestion in the gastric phase suggest that as little as 50 inulinase units (INU) and up to 800 INU per serving promote fructan hydrolysis better than the control simulations without inulinase. Liquid chromatography-mass spectrometry (LC-MS) profiling of fructo-oligosaccharides (FOS) in the gastric digestas following inulinase treatment confirms the fructolytic activity of inulinase under simulated digestive conditions. Altogether, these in vitro digestion data support the use of microbial inulinase as an exogenous enzyme supplement for reducing dietary fructan-type FODMAP exposure.

Fungal digestive enzymes promote macronutrient hydrolysis in the INFOGEST static in vitro simulation of digestion

The objective of this study was to test the hydrolytic efficacy of 6 fungal enzymes in the INFOGEST static in vitro simulation of gastrointestinal (GI) digestion. First, the INFOGEST protocol was adapted for testing of exogenous enzymes. Second, a dose-response study of 3 individual fungal proteases, a lipase, and an amylase with glucoamylase demonstrated improved dietary protein, lipid, and carbohydrate hydrolysis, respectively, from an oral nutritional supplement (ONS) under simulated gastric or GI conditions, compared to pepsin and pancreatin-based control conditions. Third, a combination of the 6 enzymes (BC-006) improved macronutrient digestion, including enhanced release of individual amino acids from ONS and mixed meal substrates. Finally, we validated digestive models of aging and proton pump inhibitor (PPI) use, and showed that BC-006 improved gastric digestion under these compromised digestive conditions. The INFOGEST static simulation is a feasible tool to rapidly screen and profile exogenous enzymes for digestive efficacy in vitro.

Update on the management of upper gastrointestinal bleeding

Upper gastrointestinal bleeding is a common emergency presentation requiring prompt resuscitation and management. Peptic ulcers are the most common cause of the condition. Thorough initial management with a structured approach is vital with appropriate intravenous fluid resuscitation and use of a restrictive transfusion threshold of 7-8 g/dL. Pre-endoscopic scoring tools enable identification of patients at high risk and at very low risk who might benefit from specific management. Endoscopy should be carried out within 24 h of presentation for patients admitted to hospital, although optimal timing for patients at a higher risk within this period is less clear. Endoscopic treatment of high risk lesions and use of subsequent high dose proton pump inhibitors is a cornerstone of non-variceal bleeding management. Variceal haemorrhage results in higher mortality than non-variceal haemorrhage and, if suspected, antibiotics and vasopressors should be administered urgently, before endoscopy. Oesophageal variceal bleeding requires endoscopic band ligation, whereas bleeding from gastric varices requires thrombin or tissue glue injection. Recurrent bleeding is managed by repeat endoscopic treatment. If uncontrolled bleeding occurs, interventional radiological embolisation or surgery is required for non-variceal bleeding or transjugular intrahepatic portosystemic shunt placement for variceal bleeding.

ACG Clinical Guideline: Upper Gastrointestinal and Ulcer Bleeding

We performed systematic reviews addressing predefined clinical questions to develop recommendations with the GRADE approach regarding management of patients with overt upper gastrointestinal bleeding. We suggest risk assessment in the emergency department to identify very-low-risk patients (e.g., Glasgow-Blatchford score = 0-1) who may be discharged with outpatient follow-up. For patients hospitalized with upper gastrointestinal bleeding, we suggest red blood cell transfusion at a threshold of 7 g/dL. Erythromycin infusion is suggested before endoscopy, and endoscopy is suggested within 24 hours after presentation. Endoscopic therapy is recommended for ulcers with active spurting or oozing and for nonbleeding visible vessels. Endoscopic therapy with bipolar electrocoagulation, heater probe, and absolute ethanol injection is recommended, and low- to very-low-quality evidence also supports clips, argon plasma coagulation, and soft monopolar electrocoagulation; hemostatic powder spray TC-325 is suggested for actively bleeding ulcers and over-the-scope clips for recurrent ulcer bleeding after previous successful hemostasis. After endoscopic hemostasis, high-dose proton pump inhibitor therapy is recommended continuously or intermittently for 3 days, followed by twice-daily oral proton pump inhibitor for the first 2 weeks of therapy after endoscopy. Repeat endoscopy is suggested for recurrent bleeding, and if endoscopic therapy fails, transcatheter embolization is suggested.

Pharmacokinetic/Pharmacodynamic Evaluation of Dexlansoprazole Infusion Injection Compared with Lansoprazole in Healthy Chinese Adults

BACKGROUND AND OBJECTIVE

This study was performed in healthy Chinese subjects to evaluate the safety and pharmacokinetic/pharmacodynamic characteristics of a novel injection formulation of dexlansoprazole in the context of single and multiple administration, compared with the original lansoprazole injection.

METHODS

Helicobacter pylori-negative healthy volunteers were recruited, and 70 participants were enrolled into five dosing groups (seven males and seven females in each group), including 15 mg once daily (qd), 15 mg every 12 h (q12h), 30 mg qd and 30 mg q12h of dexlansoprazole treatment for 5 days, as well as 30 mg q12h of lansoprazole treatment for 5 days. Blood samples were collected at scheduled time spots postdose on day 1 (first dose) and day 5 (last dose). Twenty-four-hour intragastric pH was continuously monitored on day 0 (baseline) and days 1 and 5. Dexlansoprazole and S-lansoprazole in human plasma were determined by validated chiral liquid chromatography with tandem mass spectrometry, and the pharmacokinetic parameters were determined by a non-compartmental method using Phoenix WinNonlin software. Safety assessment included changes in vital signs and laboratory tests, physical examination findings, and incidence or reports of adverse events.

RESULTS

The half-life (t_½) and clearance (CL) of dexlansoprazole were 1.76-2.06 h and 4.52-5.40 L/h, respectively, while the t_½ and CL of S-lansoprazole were 0.87-1.02 h and 34.66-35.98 L/h, respectively. No drug accumulation after repeated administration was noted. Administration of lansoprazole 30 mg resulted in higher area under the concentration-time curve from time zero to the last measurable concentration (AUC_t) of dexlansoprazole than that of dexlansoprazole 15 mg (p = 0.026). Zero to 24 h after q12h multiple dosing, median and mean intragastric pH, percentage of time with the intragastric pH above 4.0 [TpH ≥ 4.0(%)] and percentage of time with the intragastric pH above 6.0 [TpH ≥ 6.0(%)] in the dexlansoprazole 15 mg q12h group were 6.07 ± 0.61, 5.70 ± 0.76, 83.58 ± 12.34, and 53.70 ± 17.06, respectively, which was similar to the lansoprazole 30 mg q12h group, i.e. 6.15 ± 0.62, 5.88 ± 0.67, 87.26 ± 12.08 and 57.00 ± 16.35, respectively. A weak positive correlation between dexlansoprazole AUC_t and baseline-adjusted TpH ≥ 4.0(%) over 0-24 h was observed, with Pearson correlation coefficients of 0.437 (p = 0.029), while no correlation was observed between AUC_t and baseline-adjusted TpH ≥ 6.0(%) over 0-24 h.

CONCLUSION

Every 12 h intravenous dosing of dexlansoprazole up to 30 mg for 5 days was safe and well-tolerated in healthy Chinese subjects. Every 12 h dosing of dexlansoprazole 15 mg has a comparable effect of gastric acid inhibition as lansoprazole 30 mg q12h.

TRIAL REGISTRATION

ClinicalTrials.gov ID NCT03120273.

Management of acute upper gastrointestinal bleeding

Upper gastrointestinal bleeding (UGIB) is a common medical emergency, with a reported mortality of 2-10%. Patients identified as being at very low risk of either needing an intervention or death can be managed as outpatients. For all other patients, intravenous fluids as needed for resuscitation and red cell transfusion at a hemoglobin threshold of 70-80 g/L are recommended. After resuscitation is initiated, proton pump inhibitors (PPIs) and the prokinetic agent erythromycin may be administered, with antibiotics and vasoactive drugs recommended in patients who have cirrhosis. Endoscopy should be undertaken within 24 hours, with earlier endoscopy considered after resuscitation in patients at high risk, such as those with hemodynamic instability. Endoscopic treatment is used for variceal bleeding (for example, ligation for esophageal varices and tissue glue for gastric varices) and for high risk non-variceal bleeding (for example, injection, thermal probes, or clips for lesions with active bleeding or non-bleeding visible vessel). Patients who require endoscopic therapy for ulcer bleeding should receive high dose proton pump inhibitors after endoscopy, whereas those who have variceal bleeding should continue taking antibiotics and vasoactive drugs. Recurrent ulcer bleeding is treated with repeat endoscopic therapy, with subsequent bleeding managed by interventional radiology or surgery. Recurrent variceal bleeding is generally treated with transjugular intrahepatic portosystemic shunt. In patients who require antithrombotic agents, outcomes appear to be better when these drugs are reintroduced early.

Lansoprazole use and tuberculosis incidence in the United Kingdom Clinical Practice Research Datalink: A population based cohort

BACKGROUND

Recent in vitro and animal studies have found the proton pump inhibitor (PPI) lansoprazole to be highly active against Mycobacterium tuberculosis. Omeprazole and pantoprazole have no activity. There is no evidence that, in clinical practice, lansoprazole can treat or prevent incident tuberculosis (TB) disease.

METHODS AND FINDINGS

We studied a cohort of new users of lansoprazole, omeprazole, or pantoprazole from the United Kingdom Clinical Practice Research Datalink to determine whether lansoprazole users have a lower incidence of TB disease than omeprazole or pantoprazole users. Negative control outcomes of myocardial infarction (MI) and herpes zoster were also studied. Multivariable Cox proportional hazards regression was used to adjust for potential confounding by a wide range of factors. We identified 527,364 lansoprazole initiators and 923,500 omeprazole or pantoprazole initiators. Lansoprazole users had a lower rate of TB disease (n = 86; 10.0 cases per 100,000 person years; 95% confidence interval 8.1-12.4) than omeprazole or pantoprazole users (n = 193; 15.3 cases per 100,000 person years; 95% confidence interval 13.3-17.7), with an adjusted hazard ratio (HR) of 0.68 (0.52-0.89). No association was found with MI (adjusted HR 1.04; 95% confidence interval 1.00-1.08) or herpes zoster (adjusted HR 1.03; 95% confidence interval 1.00-1.06). Limitations of this study are that we could not determine whether TB disease was due to reactivation of latent infection or a result of recent transmission, nor could we determine whether lansoprazole would have a beneficial effect if given to people presenting with TB disease.

CONCLUSIONS

In this study, use of the commonly prescribed and cheaply available PPI lansoprazole was associated with reduced incidence of TB disease. Given the serious problem of drug resistance and the adverse side effect profiles of many TB drugs, further investigation of lansoprazole as a potential antituberculosis agent is warranted.

Impact of Gastric H+/K+-ATPase rs2733743 on the Intragastric pH-Values of Dexlansoprazole Injection in Chinese Subjects

Background: Not all patients with acid-related disorders receiving proton pump inhibitor (PP) treatment get adequate gastric pH control. The genetic variation of receptors, metabolic enzymes, and transporters are known to cause failures of therapies. We have conducted a study to evaluate the influence of gastric H⁺/K⁺-ATPase, CYP2C19, and ABCB1 polymorphisms on the pharmacokinetic and pharmacodynamic profiles of dexlansoprazole injection in healthy Chinese subjects.

Methods: A total of 51 subjects were enrolled for pharmacokinetic and pharmacodynamic study after a single intravenous administration of 20 or 30 mg dexlansoprazole. Plasma concentrations were determined using a chiral liquid chromatography-mass spectrometry method. The intragastric pH and baseline-adjusted intragastric pH parameters were introduced to evaluate the pharmacodynamic characters. Genotyping was performed by polymerase chain reaction.

Results: The pharmacokinetic parameters were significantly influenced by CYP2C19 phenotypes, and gastric acid secretion inhibition were affected by both gastric H⁺/K⁺-ATPase and CYP2C19 polymorphisms. Gastric H⁺/K⁺-ATPase genotypes had greater effects than CYP2C19 genotypes on the suppression of gastric acid secretion.

Conclusion: Gastric H⁺/K⁺-ATPase polymorphism may be one of the main reasons that cause insufficient gastric acid inhibition.

Pharmacokinetics, Pharmacodynamics and Safety of Multiple-Infusion Ilaprazole in Healthy Chinese Subjects

BACKGROUND AND OBJECTIVES

Ilaprazole is a novel proton pump inhibitor that provides effective and long lasting inhibition of intragastric acid secretion. The objectives of this study were to investigate the pharmacokinetics, pharmacodynamics, and safety of intravenous ilaprazole after multiple administrations in healthy Chinese subjects.

METHODS

This was an open-label and multiple-dose clinical study. Ten healthy Chinese subjects received 10 mg ilaprazole infusion once daily for 5 days. Helicobacter pylori status was examined. Blood samples were collected and intragastric pH was recorded for 24 h. Safety was assessed throughout the study.

RESULTS

There was no accumulation after multiple administrations. The mean steady-state half-life and clearance were comparable to those following single administration. Ilaprazole provided sustainable and significant intragastric pH control in terms of percentage time at pH >4, pH >6 within 24 h and mean 24-h pH values. The pH value within 24 h was affected by Helicobacter pylori infection in subjects with continuous infusion. Intravenous ilaprazole was safe and there were no serious adverse events.

CONCLUSION

Intravenous ilaprazole provided stable pharmacokinetics and pharmacodynamics at a dose of 10 mg once daily for 5 days, and was well tolerated in healthy subjects.

Pharmacokinetics and pharmacodynamics of intravenous ilaprazole in healthy subjects after single ascending doses

1. Ilaprazole is a novel proton pump inhibitor and this is the first study to investigate the pharmacokinetics, pharmacodynamics and safety of intravenous ilaprazole in healthy volunteers. 2. In this open-label, single-dose, randomized and four-period crossover study, 16 healthy Chinese subjects received ilaprazole 5, 10 or 20 mg intravenously, or 10 mg orally. Serial blood and urine samples were collected and intragastric pH was recorded within 24 h. The percentage time of intragastric pH > 6 was the major index. Safety was assessed throughout the study. 3. Plasma exposure of intravenous ilaprazole increased proportionally over the dose of 5-20 mg. Clearance and volume of distribution were independent of dose. Ilaprazole was not eliminated through urine and the absolute bioavailability was 55.2%. For the intravenous dose of 5, 10, 20 mg, and oral dose of 10 mg, the mean percentages time of intragastric pH > 6 were 47.3%, 52.8%, 68.2% and 47.5%, respectively. 4. Ilaprazole showed linear pharmacokinetics over the dose of 5-20 mg. Intravenous ilaprazole provided rapid onset of action and the potency of effect were exhibited in a dose-dependent manner. Intravenous ilaprazole was safe and well tolerated except for elevated activated partial thromboplastin time (APTT) and prothrombin time (PT).

Intermittent vs continuous proton pump inhibitor therapy for high-risk bleeding ulcers: a systematic review and meta-analysis

IMPORTANCE

Current guidelines recommend an intravenous bolus dose of a proton pump inhibitor (PPI) followed by continuous PPI infusion after endoscopic therapy in patients with high-risk bleeding ulcers. Substitution of intermittent PPI therapy, if similarly effective as bolus plus continuous-infusion PPI therapy, would decrease the PPI dose, costs, and resource use.

OBJECTIVE

To compare intermittent PPI therapy with the currently recommended bolus plus continuous-infusion PPI regimen for reduction of ulcer rebleeding.

DATA SOURCES

Searches included MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials databases through December 2013; US and European gastroenterology meeting abstracts from 2009 to 2013; and bibliographies of systematic reviews.

STUDY SELECTION

Randomized trials of patients with endoscopically treated high-risk bleeding ulcers (active bleeding, nonbleeding visible vessels, and adherent clots) comparing intermittent doses of PPIs and the currently recommended regimen (80-mg intravenous bolus dose of a PPI followed by an infusion of 8 mg/h for 72 hours).

DATA EXTRACTION AND SYNTHESIS

Duplicate independent data extraction and risk-of-bias assessment were performed. Data were pooled using a fixed-effects model or a random effects model if statistical heterogeneity was present.

MAIN OUTCOMES AND MEASURES

The primary outcome was rebleeding within 7 days; additional predefined outcomes included rebleeding within 3 and 30 days, need for urgent intervention, mortality, red blood cell transfusion, and length of hospital stay. The primary hypothesis, defined before initiation of the literature review, was that intermittent use of PPIs was noninferior to bolus plus continuous infusion of PPIs, with the noninferiority margin predefined as an absolute risk difference of 3%.

RESULTS

The risk ratio of rebleeding within 7 days for intermittent vs bolus plus continuous infusion of PPIs was 0.72 (upper boundary of 1-sided 95% CI, 0.97) and the absolute risk difference was -2.64% (upper boundary of 1-sided 95% CI, -0.28%, which is well below the predefined noninferiority margin of 3%). Risk ratios for rebleeding within 30 days and 3 days, mortality, and urgent interventions were less than 1 and mean differences for blood transfusion and hospital length of stay were less than 0, indicating that no summary estimate showed an increased risk with intermittent therapy. The upper boundaries of 95% CIs for absolute risk differences were less than 1.50% for all predefined rebleeding outcomes.

CONCLUSIONS AND RELEVANCE

Intermittent PPI therapy is comparable to the current guideline-recommended regimen of intravenous bolus plus a continuous infusion of PPIs in patients with endoscopically treated high-risk bleeding ulcers. Guidelines should be revised to recommend intermittent PPI therapy.

Intravenous ilaprazole is more potent than oral ilaprazole against gastric lesions in rats

BACKGROUND AND AIMS

Ilaprazole is a novel proton pump inhibitor that has been marketed as an oral therapy for acid-related diseases in China and Korea. This study aimed to compare the gastroprotective effects of intravenous and enteral ilaprazole in rat models.

METHODS

The rats were divided into 7-8 groups receiving vehicle, esomeprazole, and different doses of intravenous and enteral ilaprazole. The rats were then exposed to indomethacin (30 mg/kg, i.g.), or water-immersion stress and gastric lesions were examined. The effects of different treatments on histamine (10 μmol/kg/h)-induced acid secretion were also observed.

RESULTS

Intravenous ilaprazole exhibited high antiulcer activity in a dose-dependent manner. Ilaprazole at a dose of 3 mg/kg decreased ulcer number and index to the same extent as 20 mg/kg esomeprazole. Moreover, the potency of intravenous ilaprazole is superior to that of intragastric ilaprazole. In anesthetized rats, the inhibitory effect of intravenous ilaprazole on histamine-induced acid secretion is faster and longer-lasting than that of intraduodenal ilaprazole.

CONCLUSION

Intravenous ilaprazole is more potent than oral ilaprazole against indomethacin- or stress-induced gastric lesions, with faster and longer inhibition of acid secretion.

Endoscopic therapy for bleeding ulcers: an evidence-based approach based on meta-analyses of randomized controlled trials

The aim of this study was to determine appropriate endoscopic treatment of patients with bleeding ulcers by synthesizing results of randomized controlled trials. We performed dual independent bibliographic database searches to identify randomized trials of thermal therapy, injection therapy, or clips for bleeding ulcers with active bleeding, visible vessels, or clots, focusing on results from studies without second-look endoscopy and re-treatment. The primary end point was further (persistent plus recurrent) bleeding. Compared with epinephrine, further bleeding was reduced significantly by other monotherapies (relative risk [RR], 0.58 [95% CI, 0.36-0.93]; number-needed-to-treat [NNT], 9 [95% CI, 5-53]), and epinephrine followed by another modality (RR, 0.34 [95% CI, 0.23-0.50]; NNT, 5 [95% CI, 5-7]); epinephrine was not significantly less effective in studies with second-look and re-treatment. Compared with no endoscopic therapy, further bleeding was reduced by thermal contact (heater probe, bipolar electrocoagulation) (RR, 0.44 [95% CI, 0.36-0.54]; NNT, 4 [95% CI, 3-5]) and sclerosant therapy (RR, 0.56 [95% CI, 0.38-0.83]; NNT, 5 [95% CI, 4-13]). Clips were more effective than epinephrine (RR, 0.22 [95% CI, 0.09-0.55]; NNT, 5 [95% CI, 4-9]), but not different than other therapies, although the latter studies were heterogeneous, showing better and worse results for clips. Endoscopic therapy was effective for active bleeding (RR, 0.29 [95% CI, 0.20-0.43]; NNT, 2 [95% CI, 2-2]) and a nonbleeding visible vessel (RR, 0.49; [95% CI, 0.40-0.59]; NNT, 5 [95% CI, 4-6]), but not for a clot. Bolus followed by continuous-infusion proton pump inhibitor after endoscopic therapy significantly improved outcome compared with placebo/no therapy (RR, 0.40 [95% CI, 0.28-0.59]; NNT, 12 [95% CI, 10-18]), but not compared with histamine(2)-receptor antagonists. Thermal devices, sclerosants, clips, and thrombin/fibrin glue appear to be effective endoscopic hemostatic therapies. Epinephrine should not be used alone. Endoscopic therapy should be performed for ulcers with active bleeding and nonbleeding visible vessels, but efficacy is uncertain for clots. Bolus followed by continuous-infusion intravenous proton pump inhibitor should be used after endoscopic therapy.

Comparison of the enteral and intravenous lansoprazole pharmacodynamic responses in critically ill patients

BACKGROUND

While proton pump inhibitors are frequently administered in the intensive care unit, the pharmacodynamic response of acid suppression between the enteral and intravenous (IV) route is unknown.

AIM

To compare the pharmacodynamic response between enteral and IV lansoprazole in intensive care unit patients requiring stress ulcer prophylaxis therapy.

METHODS

Adult mechanically ventilated patients were randomized to receive 72 h of daily enteral [lansoprazole oral disintegrating tablet (LODT) 30 mg mixed in 10 mL of water via a nasal gastric tube] or IV lansoprazole (30 mg over 30 min) therapy. Serial blood samples were collected after the first and third dose and analysed for pharmacokinetic parameters. Pharmacodynamic determination of intragastric pHmetry began prior to the first dose and continued for 72 h using a single channel pH microelectrode.

RESULTS

Nineteen intensive care unit patients were randomized [LODT (n = 10); IV-L (n = 9)]. LODT bioavailability was 76%. LODT maintained gastric pH > 4 longer than IV-L at both 24 h (7.4 vs. 5.9 h; P = 0.039) and 72 h (10.4 and 8.9 h; P = 0.046) and resulted in a greater average pH over the first 24 h (3.67 vs. 2.89; P = 0.03).

CONCLUSION

Despite a lower bioavailability, enteral lansoprazole suppresses acid in intensive care unit patients to a greater extent than IV lansoprazole.

Intragastric pH with oral vs intravenous bolus plus infusion proton-pump inhibitor therapy in patients with bleeding ulcers

BACKGROUND & AIMS

Intravenous bolus plus infusion proton pump inhibitor (PPI) therapy is recommended for patients with bleeding ulcers and higher risk stigmata. If frequent oral dosing of PPIs provided similar antisecretory effect, this might be preferred based on ease and cost.

METHODS

Patients presenting with overt bleeding due to ulcers had intragastric pH probes placed after endoscopy and baseline pH recorded. They were randomly assigned to intravenous lansoprazole (90-mg bolus followed by 9-mg/h infusion) or oral lansoprazole (120-mg bolus followed by 30 mg every 3 hours). pH was recorded for 24 hours.

RESULTS

Intragastric pH was > 6 for 67.8% of the study period with intravenous PPI (n = 32) and 64.8% with oral PPI (n = 34): difference, 3.0%; 95% confidence interval (CI): -9.2% to 15.2%. Intragastric pH was > 6 for > 60% of the study period in 22 (68.8%) patients receiving intravenous and 22 (64.7%) patients receiving oral PPI: difference, 4.0%; 95% CI: -18.7% to 26.8%. At 1 hour, mean pHs for intravenous vs oral were 5.3 +/- 0.4 vs 3.3 +/- 0.4, respectively (difference, 2.0; 95% CI: 0.8-3.1; P = .001). At > or = 1.5 hours, 95% CIs of the differences for all hourly mean pHs included zero. Mean pH rose above 6 after 2-3 hours of intravenous PPI and 3-4 hours of oral PPI.

CONCLUSIONS

Frequent oral PPI may be able to replace the currently recommended intravenous bolus plus infusion PPI therapy in patients with bleeding ulcers, although the possibility that intravenous PPIs are superior cannot be definitively excluded given our relatively wide confidence intervals. Intravenous PPI provides more rapid increase in pH, reaching mean pH of 6 approximately 1 hour sooner than oral PPI.

Oral pantoprazole in the form of granules or tablets are pharmacodynamically equivalent in suppressing acid output in patients with gastro-oesophageal reflux disease and a history of erosive oesophagitis

AIM

To demonstrate the pharmacodynamic comparability between oral 40 mg pantoprazole delayed-release granules and tablets.

METHODS

This was a multicentre, randomized, open-label, 2-period, 2-sequence, 9-week crossover study in patients aged 18-65 years with gastro-oesophageal reflux disease and documented erosive oesophagitis. The primary endpoint was a comparison of the inhibition of pentagastrin-stimulated maximum acid output (MAO) at steady state after once daily dosing for 1 week and 23 h after the last dose of pantoprazole granules and tablets. Basal acid output was measured prior to MAO. Standard safety evaluations were performed. The one-sided t-test was used to test the null hypothesis that granules - 1.2 x tablet >/= 0 against the alternative hypothesis that this difference was <0 for both MAO and basal acid output values.

RESULTS

Sixty patients completed the study. The mean MAO values were 7.11 +/- 4.98 and 7.29 +/- 4.77 mmol/h, while the mean basal acid output values were 0.74 +/- 0.91 and 0.58 +/- 0.63 mmol/h for the granules and tablets, respectively. The two formulations were shown statistically to be pharmacodynamically equivalent in suppressing MAO (P = 0.006), safe and well tolerated.

CONCLUSION

Patients with gastro-oesophageal reflux disease who are unable to swallow the tablet may safely be prescribed the pantoprazole sodium granules.

Effects of Uptake and Efflux Transporter Inhibition on Erythromycin Breath Test Results

The erythromycin breath test (EBT) is a standard test used to evaluate the extent of CYP3A4 activity. This study examines whether presumed changes in CYP3A4 activity are in fact related to inhibition of an uptake organic anion transporter using rifampin and inhibition of the efflux hepatic P-glycoprotein transporter using lansoprazole. Three EBT tests in healthy adults were conducted: EBT alone, with lansoprazole, and with rifampin. For all subjects, lansoprazole treatment increased respiratory (14)C excretion by +0.25+/-0.51 met/h (P=0.07) and rifampin decreased (14)C excretion by -0.44+/-0.40 met/h (P<0.001) compared with baseline. Comparing lansoprazole to rifampin, (14)C excretion increased by +0.69+/-0.50 met/h (P<0.001). Only women had significant changes after drug infusion: (14)C excretion after rifampin -0.40+/-0.36 met/h (P=0.018) and +0.47+/-0.44 met/h (P=0.018) after lansoprazole. Relying on EBT without considering transporter interactions can lead to errors in interpreting the degree of CYP3A4 metabolism.

Inhibition of atazanavir oral absorption by lansoprazole gastric acid suppression in healthy volunteers

STUDY OBJECTIVE

To determine whether the pharmacokinetics of atazanavir, a protease inhibitor used to treat human immunodeficiency virus (HIV) infection, are altered by its coadministration with lansoprazole, a proton pump inhibitor.

DESIGN

Single-dose, open-label, complete-crossover study.

SETTING

Clinical research center.

SUBJECTS

Ten healthy adult volunteers.

MEASUREMENTS AND MAIN RESULTS

In phase A, subjects received a single oral dose of atazanavir 400 mg alone. In phase B, the same subjects received oral lansoprazole 60 mg, and after 24 hours they were given a second dose of oral lansoprazole 60 mg with atazanavir 400 mg. Eleven blood samples were collected from each subject over a 24-hour period for determination of atazanavir plasma concentrations by a validated high-performance liquid chromatography assay. Pharmacokinetic analysis was performed by standard noncompartmental methods. Nine subjects completed the study, and no significant adverse events were reported. Absorption of atazanavir was significantly reduced when it was coadministered with lansoprazole, as evidenced by a 94% decline in mean area under the concentration-time curve during the 24 hours after administration (AUC(0-24)) (p<0.01). The mean +/- SD AUC(0-24) for phase A was 16.3 +/- 9.0 microM x hour versus 0.95 +/- 1.8 microM x hour for phase B (p<0.01). The mean +/- SD maximum concentration of atazanavir was 3.2 +/- 1.7 microM for phase A and 0.13 +/- 0.19 microM for phase B (p<0.01).

CONCLUSION

Acid suppression markedly reduced the bioavailability of atazanavir in this group of healthy volunteers. Based on these results, atazanavir should not be coadministered with lansoprazole or other proton pump inhibitors.

Lansoprazole regimens that sustain intragastric pH > 6.0: an evaluation of intermittent oral and continuous intravenous infusion dosages

BACKGROUND

Orally and intravenously administered proton pump inhibitors have been shown to reduce rebleeding rates, surgery and transfusion requirement.

AIM

To compare lansoprazole intravenous and orally disintegrating tablet (Prevacid SoluTab) regimens with a pantoprazole intravenously administered regimen in sustaining intragastric pH >6.0.

METHODS

Two similarly designed three-way, randomized crossover studies each enrolled 36 Helicobacter pylori-negative healthy volunteers. Study 1 regimens included intravenously administered bolus followed by 24-h continuous infusion (lansoprazole 90 mg, 6 mg/h; lansoprazole 120 mg, 6 mg/h; pantoprazole 80 mg, 8 mg/h). Study 2 regimens included intravenous bolus followed by lansoprazole orally disintegrating tablet or intravenous continuous infusion for 24 h (lansoprazole 90 mg, lansoprazole orally disintegrating tablet 60 mg every 6 h; lansoprazole 120 mg, 9 mg/h; pantoprazole 80 mg, 8 mg/h). Percentage of time pH >6.0 was assessed with 24-h intragastric pH monitoring.

RESULTS

All regimens produced comparable gastric acid suppression. In both studies, regimens superior to pantoprazole included lansoprazole 90 mg, 6-mg/h; lansoprazole 90 mg, lansoprazole orally disintegrating tablet 60 mg q.d.s. and lansoprazole 120 mg, 9 mg/h (P < or = 0.013). The lansoprazole 120-mg, 6-mg/h regimen (P = 0.082) was not superior to pantoprazole in percentage of time intragastric pH >6.0. Mild reaction at the intravenous injection site was the most frequently reported adverse event.

CONCLUSIONS

The intravenous bolus and continuously infused lansoprazole or intravenous bolus and intermittent lansoprazole orally disintegrating tablet regimens are as effective as intravenous pantoprazole in sustaining intragastric pH >6.0.

Intravenous and oral lansoprazole are equivalent in suppressing stimulated acid output in patient volunteers with erosive oesophagitis

BACKGROUND

Some patients requiring acid suppression may be unable to take oral medications.

AIM

To compare the gastric acid inhibition effects of lansoprazole 30 mg administered either intravenous or orally in erosive oesophagitis patients.

METHODS

The study included 87 Helicobacter pylori-negative patients with erosive oesophagitis. Each patient received 7 days of lansoprazole 30 mg orally prior to being randomized in a 3:1 fashion to intravenously lansoprazole 30 mg or intravenously placebo for 7 days. Basal acid output and pentagastrin-stimulated acid output were measured on days 8, 9 and 15.

RESULTS

Median pentagastrin-stimulated acid output was 7.2 mmol/h after 7 days of oral lansoprazole. The median pentagastrin-stimulated acid output increased to 7.6 mmol/h after 7 days of intravenous lansoprazole compared with 26.9 mmol/h after intravenous placebo (P < 0.001).

CONCLUSIONS

Lansoprazole 30 mg administered intravenous was equivalent to the 30 mg oral capsule in gastric acid suppression. Intravenous proton pump inhibitor therapy represents an important treatment option for those with acid-related diseases who are unable to take oral medications.

Intravenous Lansoprazole

An intravenous formulation of lansoprazole, a proton pump inhibitor, is approved for use in patients with erosive oesophagitis who are temporarily unable to take oral lansoprazole. In healthy volunteers, oral and intravenous lansoprazole 30 mg/day were equivalent in suppressing basal and pentagastrin-stimulated maximum gastric acid output. Moreover, the mean 24-hour intragastric pH did not differ significantly following oral or intravenous administration of lansoprazole and was significantly higher with both formulations than with intravenous polyethylene glycol vehicle. After treatment for 7 days in patients with erosive oesophagitis, intravenous lansoprazole (30 mg/day) recipients had significantly lower median stimulated and basal gastric acid output measurements than placebo recipients. Median pentagastrin-stimulated gastric acid output levels were equivalent after 7 days treatment with intravenous or oral lansoprazole. Intravenous lansoprazole is generally well tolerated. All adverse events experienced by patients with erosive oesophagitis who received intravenous lansoprazole were mild or moderate in severity.