Selection of drugs to treat gastro-oesophageal reflux disease: the role of drug interactions

In Vitro Metabolism and Transport Characteristics of Zastaprazan

Zastaprazan (JP-1366), a novel potassium-competitive acid blocker, is a new drug for the treatment of erosive esophagitis. JP-1366 is highly metabolized in human, mouse, and dog hepatocytes but moderately metabolized in rat and monkey hepatocytes when estimated from the metabolic stability of this compound in hepatocyte suspension and when 18 phase I metabolites and 5 phase II metabolites [i.e., N-dearylation (M6), hydroxylation (M1, M19, M21), dihydroxylation (M7, M8, M14, M22), trihydroxylation (M13, M18), hydroxylation and reduction (M20), dihydroxylation and reduction (M9, M16), hydrolysis (M23), hydroxylation and glucuronidation (M11, M15), hydroxylation and sulfation (M17), dihydroxylation and sulfation (M10, M12), N-dearylation and hydroxylation (M3, M4), N-dearylation and dihydroxylation (M5), and N-dearylation and trihydroxylation (M2)] were identified from JP-1366 incubation with the hepatocytes from humans, mice, rats, dogs, and monkeys. Based on the cytochrome P450 (CYP) screening test and immune-inhibition analysis with CYP antibodies, CYP3A4 and CYP3A5 played major roles in the metabolism of JP-1366 to M1, M3, M4, M6, M8, M9, M13, M14, M16, M18, M19, M21, and M22. CYP1A2, 2C8, 2C9, 2C19, and 2D6 played minor roles in the metabolism of JP-1366. UDP-glucuronosyltransferase (UGT) 2B7 and UGT2B17 were responsible for the glucuronidation of M1 to M15. However, JP-1366 and active metabolite M1 were not substrates for drug transporters such as organic cation transporter (OCT) 1/2, organic anion transporter (OAT) 1/3, organic anion transporting polypeptide (OATP)1B1/1B3, multidrug and toxic compound extrusion (MATE)1/2K, P-glycoprotein (P-gp), and breast cancer-resistant protein (BCRP). Only M1 showed substrate specificity for P-gp. The findings indicated that drug-metabolizing enzymes, particularly CYP3A4/3A5, may have a significant role in determining the pharmacokinetics of zastaprazan while drug transporters may only have a small impact on the absorption, distribution, and excretion of this compound.

High concentrations of nirmatrelvir/ritonavir in critically ill patients receiving continuous renal replacement therapy

OBJECTIVES

Nirmatrelvir/ritonavir is a highly efficacious agent against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Although dose adjustment is recommended in patients with renal impairment according to the package insert for Paxlovid (Pfizer), there is no dose recommendation for patients with severe renal impairment who require continuous renal replacement therapy (CRRT).

METHODS

To characterise the features of nirmatrelvir/ritonavir in critically ill Chinese patients undergoing CRRT, therapeutic drug monitoring of nirmatrelvir/ritonavir was performed by high-performance liquid chromatography tandem mass spectrometry assay in eight patients.

RESULTS

Nirmatrelvir trough concentrations ranged from 3325.34 ng/mL to 15 625.46 ng/mL. Concentrations were up to 7-fold higher compared with patients with normal renal function and 2-fold higher compared with patients with end-stage renal disease undergoing haemodialysis.

CONCLUSIONS

These results suggest that a dose reduction should be implemented in the treatment of patients with CRRT.

Integration of a Physiologically Based Pharmacokinetic and Pharmacodynamic Model for Tegoprazan and Its Metabolite: Application for Predicting Food Effect and Intragastric pH Alterations

A physiologically based pharmacokinetic/pharmacodynamic (PBPK/PD) model for tegoprazan and its major metabolite M1 was developed to predict PK and PD profiles under various scenarios. The PBPK model for tegoprazan and M1 was developed and predicted using the SimCYP^® simulator and verified using clinical study data obtained after a single administration of tegoprazan. The established PBPK/PD model was used to predict PK profiles after repeated administrations of tegoprazan, postprandial PK profiles, and intragastric pH changes. The predicted tegoprazan and M1 concentration-time profiles fit the observed profiles well. The arithmetic mean ratios (95% confidence intervals) of the predicted to observed values for the area under the curve (AUC_{0-24 h}), maximum plasma drug concentration (C_max), and clearance (CL) for tegoprazan and M1 were within a 30% interval. Delayed time of maximum concentration (T_max) and decreased C_max were predicted in the postprandial PK profiles compared with the fasted state. This PBPK/PD model may be used to predict PK profiles after repeated tegoprazan administrations and to predict differences in physiological factors in the gastrointestinal tract or changes in gastric acid pH after tegoprazan administration.

Urinary Metabolomic Profiling after Administration of Corydalis Tuber and Pharbitis Seed Extract in Healthy Korean Volunteers

Pharmacometabolomics is a useful tool to identify biomarkers that can assess and predict response after drug administration. The primary purpose of pharmacometabolomics is to better understand the mechanisms and pathways of a drug by searching endogenous metabolites that have significantly changed after drug administration. DA-9701, a prokinetic agent, consists of Pharbitis seed and Corydalis tube extract and it is known to improve the gastrointestinal motility. Although the overall mechanism of action of DA-9701 remains unclear, its active ingredients, corydaline and chlorogenic acid, act as a 5-HT3 and D2 receptor antagonist and 5-HT4 receptor agonist. To determine the significant metabolites after the administration of DA-9701, a qualitative analysis was carried out using ultra-high performance liquid chromatography coupled with orbitrap mass spectrometer followed by a multivariate analysis. Seven candidates were selected and a statistical analysis of fold change was performed over time. Our study concluded that all the seven selected metabolites were commonly involved in lipid metabolism and purine metabolism.

Ventricular Arrhythmia Risk Based on Ethnicity in COVID-19 Patients on Hydroxychloroquine and Azithromycin Combination: Viewpoint

There are many reports available now, which are mostly observational or registry trial outcomes having varied results on coronavirus 2019 (COVID-19) patients put on hydroxychloroquine and azithromycin combination. Some are showing increased in-hospital mortality and ventricular arrhythmia increase, while some are showing overall benefit with significant viral RNA load reduction. Everyday things are getting more complicated with the publication of these different outcomes. This needs to be addressed.

Xenobiotic Metabolising Enzymes: Impact on Pathologic Conditions, Drug Interactions and Drug Design

Background:

The biotransformation of xenobiotics is a homeostatic defensive response of the body against bioactive invaders. Xenobiotic metabolizing enzymes, important for the metabolism, elimination and detoxification of exogenous agents, are found in most tissues and organs and are distinguished into phase I and phase II enzymes, as well as phase III transporters. The cytochrome P450 superfamily of enzymes plays a major role in the biotransformation of most xenobiotics as well as in the metabolism of important endogenous substrates such as steroids and fatty acids. The activity and the potential toxicity of numerous drugs are strongly influenced by their biotransformation, mainly accomplished by the cytochrome P450 enzymes, one of the most versatile enzyme systems.

Objective:

In this review, considering the importance of drug metabolising enzymes in health and disease, some of our previous research results are presented, which, combined with newer findings, may assist in the elucidation of xenobiotic metabolism and in the development of more efficient drugs.

Conclusion:

Study of drug metabolism is of major importance for the development of drugs and provides insight into the control of human health. This review is an effort towards this direction and may find useful applications in related medical interventions or help in the development of more efficient drugs.

Concomitant drugs with low risks of drug-drug interactions for use in oncology clinical trials

BACKGROUND

Drug-drug interactions (DDIs) may occur with investigational drugs and affect patient safety, trial outcomes, and drug development. A list of preferred drugs with minimal risks of DDIs for treatment of symptoms or comorbidities frequently encountered by cancer patients would be helpful.

METHODS

We reviewed the literature to assess DDIs reported for the main drugs available for treatment of symptoms/comorbidities frequently encountered by cancer patients. Reviews and relevant original articles cited were retrieved and analyzed, and the following data were collected and double-checked: pharmacological properties; effects, if any, of drugs on CYP enzymes, membrane transporters, and QT interval; and involvement in significant DDIs.

RESULTS

A list of preferred drugs with minimal risks of DDIs was compiled.

CONCLUSION

Acknowledging for heterogeneity in data sources, prevention of unexpected DDIs during clinical trials may be improved by using this list of preferred drugs for the management of study patient's symptoms.

Implications of over-the-counter proton pump inhibitors for patient counseling by pharmacists

The article reviews the literature on the role of the pharmacist in patient counseling and discusses how that role may apply to patients with frequent heartburn who are seeking an over-the-counter (OTC) treatment. Searches of the National Library of Medicine PubMed database were conducted using the terms "heartburn," "nonprescription," "therapy," "pharmacist," and "counseling," supplemented by additional searches on counseling for prescription products, and by the author's knowledge of pharmacy practice and the scientific literature. Accurate recognition of the signs of heartburn are an important first step in counseling a patient on the appropriate OTC medication; immediate referral to a health care provider is mandatory if cardiac pain or certain gastrointestinal symptoms are present. When counseling a patient about treatments for heartburn, the pharmacist should practice effective listening in an environment that is conducive to communication by the patient. Proton pump inhibitors are effective for the treatment of heartburn; the histamine2 receptor antagonists and antacids should also be considered for appropriate patients. Adverse events have been noted with proton pump inhibitors; however, overall the benefits significantly outweigh the risks and problems are unlikely to arise during the 2-week duration of OTC treatment of heartburn. Pharmacists can provide valuable services to patients with frequent heartburn, particularly with regard to counseling about the condition and appropriate OTC therapy. The availability of numerous OTC products, including antacids, histamine2 receptor antagonists, and proton pump inhibitors, enables pharmacists to fulfill an important clinical role and improve patient satisfaction.

Simo decoction promotes contraction of antral circular smooth muscle mainly via muscarinic M3 receptor

ETHNOPHARMACOLOGICAL RELEVANCE

Simo Decoction (SMD), a traditional Chinese medicine, included four elements, such as Fructus aurantii, Radix aucklandiae, Semen arecae and Radix linderae. It has been used to improve gastrointestinal dysmotility in clinical practice for a long history in China. However, the explicit mechanisms are unclear. The aim of this study was to investigate the effect of SMD on contractions of antral circular smooth muscle strips of Sprague-Dawley (SD) rats and its underlying mechanism.

MATERIALS AND METHODS

The antral circular strips were prepared in the organ bath under baseline or to be incubated with muscarinic receptor antagonist atropine (10(-6)M), muscarinic M3 receptor antagonist 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP) (0.4×10(-6)M), muscarinic M2 receptor antagonist gallamine (10(-6)M), adrenergic receptor agonist adrenaline (10(-7)M), exogenous nitric oxide (NO) donor l-arginine (10(-4)M), nicotinic receptor antagonist hexamethonium chloride (10(-4)M) and Ca(2+) channel antagonist nifedipine (30nM), and consecutive concentrations of SMD were added to the bath to observe the strip responses. As a control, the responses of strips after administration with the same volume of Krebs solution as SMD were also noted. The strip responses to acetylcholine (10(-7)-10(-3)M) were also noted in organ bath to compare with SMD-induced contraction.

RESULTS

SMD dose-dependently evoked hypercontractility of antral circular strips, and the maximal contractile effect of circular smooth muscle induced by SMD was significantly higher than that induced by acetylcholine (10(-3)M). The responses of antral circular strips to SMD were completely antagonized by atropine, 4-DAMP or 4-DAMP+gallamine, but partly inhibited by gallamine and partly suppressed by adrenaline, l-arginine, hexamethonium chloride and nifedipine.

CONCLUSIONS

SMD promotes contractions of antral circular strips in rats mainly via activation of muscarinic M3 receptor, but partly via activation of muscarinic M2 receptor, Ca(2+) channel and nicotinic receptor, inhibition of adrenergic receptor and releasing of NO.

Effects of DA-9701, a novel prokinetic agent, on gastric accommodation in conscious dogs

BACKGROUND AND AIM

DA-9701, a novel prokinetic agent formulated with Pharbitis Semen and Corydalis Tuber, has strong prokinetic effects, and enhances gastric compliance in conscious dogs. In this study, the effects of DA-9701 on gastric accommodation were studied in conscious dogs.

METHODS

Beagle dogs with an implanted gastric cannula in the stomach were used in this study. After an overnight fast, the dogs received DA-9701 orally, or served as a positive control that received sumatriptan or a negative control before ingestion of a meal. The basal and postprandial gastric volumes were monitored at a constant operating pressure using an electronic barostat. To investigate the long-lasting effects on increased postprandial gastric volume, the area under the volume versus time curve (AUC) was calculated.

RESULTS

DA-9701 significantly increased the basal gastric volume compared to the negative controls (P < 0.05); the effects were comparable to sumatriptan. DA-9701 and sumatriptan significantly increased gastric accommodation compared to the negative control (P < 0.05). In the negative control, the gastric volume reached the maximal volume 40 min after the meal, and then gradually decreased. However, with DA-9701, the increased gastric volume remained significantly elevated for 60 min postprandially (P < 0.05). DA-9701 significantly increased the value of AUC compared to the negative control; this was observed during both the early and late postprandial phases (P < 0.05).

CONCLUSIONS

A novel prokinetic agent, DA-9701, improved gastric accommodation by increasing the postprandial gastric volume; these effects persisted for 60 min after a meal.

Prescribing of inappropriate medication in nursing home residents in Germany according to a French consensus list: a cross-sectional cohort study

PURPOSE

The current use of inappropriate medication in elderly nursing home residents (NHRs) in Germany is unclear. We therefore set out to analyse the frequency and patterns of potentially inappropriate drug prescriptions in elderly NHRs in Germany.

METHODS

We utilised prescription data for NHRs 65 years or older from a large German health insurance company during a period of 3 months. Inappropriate drugs were identified from a recently reported French consensus list.

RESULTS

Data for 7271 (83.7%) females and 1414 (16.3%) males were available for analysis. The average age was 83.6 ± 7.3 years. Overall 48 inappropriate drugs were prescribed resulting in a total of 3825 inappropriate drug prescriptions which accounted for 4.3% of all documented prescriptions (n = 88,695). One thousand nine hundred and three (21.9%) residents received at least one inappropriate drug prescription. Using logistic regression we detected no significant influence of gender or level of care on frequency of inappropriate prescriptions. However, age had a significant influence; with increasing age the frequency of residents receiving inappropriate medications decreased steadily (r = -0.92, p = 0.003) and ranged from a maximum of 32.8% in the group between 65 and 69 years to a minimum of 15.2% in residents older than 94 years. This observation was paralleled by a significant and continuous decrease of drug prescription rates with increasing age (r = -0.88, p = 0.009).

CONCLUSION

The present analysis demonstrates that about one out of five elderly NHRs received at least one inappropriate drug prescription. Additional studies may aim to establish a list of frequently prescribed inappropriate drugs for Germany.

Role of the primary care provider in the diagnosis and management of heartburn

BACKGROUND

Heartburn affects an estimated 42% of the US population. Often, patients are able to recognize symptoms and self-treat heartburn; however, patients with more persistent and/or troublesome symptoms should be evaluated by a physician or other healthcare provider.

SCOPE

This review focuses on the role of the primary care provider in the diagnosis and treatment of heartburn.

METHODS

A search was conducted on PubMed (to November 2009) and articles relevant to the management of heartburn by a primary care provider topic were selected.

FINDINGS

Diagnostic tools, such as endoscopy, and ambulatory pH monitoring, are recommended for advanced assessment of patients with frequent heartburn to avert misdiagnosis and to identify complications of reflux disease. Over-the-counter and prescription treatments for frequent heartburn symptoms include antacids, histamine(2)-receptor antagonists (H(2)RAs), antacid/H(2)RA combinations, and proton pump inhibitors (PPIs). Among these, PPIs represent the mainstay of acute and maintenance treatment regimens in reflux disorders and are more effective than H(2)RAs for long-term use due to the development of tolerance to the latter therapy. While once-daily PPI therapy may be sufficient in most patients, a few may require twice-daily PPI therapy to alleviate their symptoms. This review is limited by its relatively narrow focus on articles cited in PubMed.

CONCLUSION

The primary care provider is ideally situated to advise patients on the best treatment option for their condition and to provide follow-up care if required.

Gastroprokinetic effects of DA-9701, a new prokinetic agent formulated with Pharbitis Semen and Corydalis Tuber

To develop a therapeutic for functional dyspepsia (FD), a prokinetic agent, DA-9701 has been newly formulated with Pharbitis Semen and Corydalis Tuber and we evaluated the gastroprokinetic effects of DA-9701 in comparison with conventional prokinetics. Oral administration with DA-9701 not only significantly accelerated gastric emptying in normal rats but also restored the delayed gastric emptying caused by apomorphine and cisplatin up to almost normal levels. For gastrointestinal transit, DA-9701 caused FITC-dextran to travel a significantly longer distance than the control, and in the delayed GI transit models induced by laparotomy and atopine, DA-9701 considerably increased the values of mean geometric center (MGC), while the conventional prokinetics rarely showed significant effects. Furthermore, DA-9701 drastically increased the gastric accommodation in Beagle dogs, shifting the pressure-volume curve toward considerably higher volume compared to the control, which was comparable to that of cisapride. These results indicate that DA-9701 has potential as a safe and effective therapeutic for FD patients with abnormalities in GI motor function.

Diets and circadian rhythms: challenges from biology for medicine

Autoimmune diseases such as rheumatoid arthritis and gastrointestinal disorders such as stomach ulcers are often treated with drugs. NSAIDs, a common treatment in rheumatoid arthritis, may cause stomach ulcers which call for additional medications, notably antacids in the sense of drugs that suppress acid secretion by the stomach. Infection with Helicobacter pylori also plays a role in the ulcers. The infection is typically treated with antibiotics added to antacids. Considering NSAIDs and antacids, we suspect that overmedication is common to the extent that particular diets are a better option. Current research and current treatments with these drugs are also problematic since circadian rhythms are mostly disregarded. All the processes involved in the disorders treated show marked variations in the course of the day. Hence experiments conforming to the guidelines of evidence-based medicine, and treatments in line with them, have outcomes strongly depending on the time factor. This calls for reforms in medicine with fresh inputs from biology.

Application of the Bradford Hill Criteria to Assess the Causality of Cisapride-Induced Arrhythmia

INTRODUCTION

The Bradford Hill criteria are a widely used, useful tool for the assessment of biomedical causation. We have examined their application to pharmacovigilance using the example of cisapride-induced QTc interval prolongation/arrhythmia.

METHODS

A literature search was conducted using MEDLINE, EMBASE, Reactions Weekly and regulatory websites to identify evidence for the association between cisapride and QTc interval prolongation/arrhythmia that had been published in the English language. Two hundred and five publications were identified as being potentially suitable for the study. After excluding irrelevant articles, studies on high-risk populations and review articles, 70 publications were assessed using the Bradford Hill criteria. These included 24 case reports, case series or spontaneous report summaries; eight epidemiological studies; 22 clinical studies; and 16 experimental (in vivo and in vitro) publications.

RESULTS

The most compelling evidence for an association between cisapride use and QTc interval prolongation/arrhythmia came from case/spontaneous reports and biological plausibility. Considering the rare incidence of serious cardiac events, these criteria formed the basis for the strength of the association. The number of reports from different populations showed consistency. Specificity was supported by clinical and cardiographic characterisation of the events. There were temporal relationships between the events and the initiation of cisapride treatment, increases in the dosage and the receipt of interacting medications. The relationships between the adverse events and the latter two factors exhibited biological gradients. Experimental evidence could be found from biological models, as well as reports of positive dechallenge and/or rechallenge found in individual patients. Cisapride was found to bind the human ether-a-go-go-related gene (HERG) potassium channel, which provides a plausible mechanism for QTc interval prolongation/arrhythmia. Other QTc interval-prolonging/arrhythmic drugs that also bind to HERG provided an analogy for cisapride causing QTc interval prolongation/arrhythmia via this mechanism. The evidence provided by clinical studies was inconsistent, and epidemiological studies failed to demonstrate an association. Nevertheless, this did not prevent the assessment of causation.

DISCUSSION

This study showed how different types of evidence found in pharmacovigilance can be evaluated using the Bradford Hill criteria. Further work is required to examine how the criteria can be applied to different types of adverse events and how they may be applied to pharmacovigilance.

Role of pantoprazole in the treatment of gastro-oesophageal reflux disease

The diagnosis and treatment of gastro-oesophageal reflux disease (GERD) presents many problems, despite the fact that significant advances have been made in recent years in the understanding of its pathogenesis and symptomatology. GERD affects many people and has a significant negative impact on patient quality of life. Heartburn is the most common symptom of GERD which occurs with and without oesophagitis. The predominant causative factor for symptoms is prolonged contact of oesophageal mucosa with refluxed acid and pepsin. Proton pump inhibitors (PPIs) are the most effective treatment for GERD: overall proportions of patients with healing and complete heartburn relief are markedly higher with PPIs than with alternative treatment strategies. Furthermore, the speed of healing and heartburn relief with PPIs is almost twice as rapid as with any other form of therapy. The present review focuses on the effectiveness and safety of the PPI, pantoprazole. The data show that the compound is highly effective in GERD patients with and without oesophagitis. Pantoprazole has an excellent safety record and shows only minor interaction with other drugs.

Lack of pharmacokinetic interaction between linezolid and antacid in healthy volunteers

Several antibiotics show significant pharmacokinetic interactions when they are given orally concomitantly with antacids. The objective of this study was to evaluate the effects of antacid (containing magnesium) on the pharmacokinetics of linezolid. A single dose of 600 mg linezolid was given orally alone and 10 min after administration of the antacid Maalox 70mVal, which contains 600 mg magnesium hydroxide and 900 mg aluminum hydroxide, to nine healthy males and nine healthy females in a crossover and randomized study. Linezolid plasma concentrations were determined by high-performance liquid chromatography, and pharmacokinetic parameters were calculated for both treatments. Coadministration with antacids did not change the pharmacokinetics of linezolid. The ratios (90% confidence intervals) of the individual values of the area under the concentration-time curve and the maximum concentration in plasma (C(max)) (linezolid plus antacid versus linezolid alone) were 1.01 (0.99 to 1.02) and 0.99 (0.96 to 1.02), respectively. Likewise, no significant difference in any of the other pharmacokinetic parameters was observed between the treatment groups (the time to C(max), lag time, volume of distribution [V/F], and clearance [CL/F]). However, a significant sex difference was observed for AUC, C(max), V/F, and CL/F; and these differences could be almost completely explained by the differences in body weight between males and females. No clinically relevant adverse effects were detected under either condition. The coadministration of antacids had no effect on the pharmacokinetics of linezolid. This demonstrates that the oral absorption of linezolid was not affected by the presence of antacids containing magnesium hydroxide and aluminum hydroxide. Antacids can be safely administered together with linezolid.

Recent advances in the treatment of GERD in the elderly: focus on proton pump inhibitors

The prevalence of gastroesophageal reflux disease (GERD) increases with age, and older people are more likely to develop severe disease. Studies of elderly patients with GERD indicate differences in presentation and diagnosis, compared with GERD in younger adults. Indeed, an older patient with GERD may present with atypical symptoms such as dysphagia, vomiting, weight loss, anaemia and anorexia, and less frequently with typical symptoms such as heartburn or acid regurgitation. These findings are attributed to pathophysiological changes in esophageal function that occur with age. Therefore, GERD in elderly patients is more likely to be poorly diagnosed or undiagnosed. Although few studies have concentrated specifically on elderly patients, the proton pump inhibitors (PPIs) have been shown to be more effective than histamine receptor antagonists for healing reflux esophagitis and for preventing its recurrence when they are given as maintenance therapy. In addition, the PPIs seem to be safe both in short- and in long-term therapy of elderly patients with GERD.

Metoclopramide induced dystonia in children: two case reports

Metoclopramide is a dopamine antagonist that is widely used in gastroesophageal disease and chemotherapy-induced emesis in the paediatric population. It is also prescribed in nausea and vomiting caused by respiratory tract infections and enteritis in practice. The primary side-effect of the drug is extrapyramidal reactions with incidences as high as 25% in children. We report two cases, one of which was referred to our emergency department as encephalitis and the other as tetany, but which were just acute dystonic reactions caused by metaclopramide, even though the patients had used the drug in the recommended dosages. The adverse effects of the drug can be seen at normal doses. These dystonic reactions caused by metaclopramide can easily be confused with other diseases, because dystonia is not seen frequently in paediatric practice whatever the cause.

Efficacy and safety of lansoprazole in adolescents with symptomatic erosive and non-erosive gastroesophageal reflux disease

OBJECTIVES

To assess the efficacy and safety of lansoprazole in the treatment of adolescents with symptomatic, endoscopically proven, non-erosive gastroesophageal reflux disease and erosive esophagitis.

METHODS

Adolescents between 12 and 17 years of age with esophagitis were enrolled in this open-label trial and treated with lansoprazole 15 mg (non-erosive) or 30 mg (erosive) once daily for 8 weeks. If unhealed at week 8, those with erosive esophagitis were treated with an additional 4 weeks of lansoprazole 30 mg once daily.

RESULTS

Lansoprazole produced a significant reduction from baseline in the median percentage of days with reflux symptoms (91 to 43% in the 64 adolescents with non-erosive disease and 85 to 16% in the 23 adolescents with erosive esophagitis, P < or = 0.001 for each comparison). At week 8, mucosal healing had occurred in 95% (21 of 22) of those with erosive esophagitis. Treatment-related adverse events were reported by 19% of patients with non-erosive and 4% of patients with erosive esophagitis. Headache (7%), abdominal pain (5%), nausea (3%) and dizziness (3%) were the most frequently reported adverse events. One patient discontinued treatment early because of dizziness and vomiting. An elevation in mean serum gastrin from baseline (59 pg/mL at pretreatment to 80 pg/mL at final visit) was observed.

CONCLUSION

Lansoprazole 15 mg or 30 mg once daily reduced symptoms of gastroesophageal reflux in adolescents with non-erosive gastroesophageal reflux disease and erosive esophagitis, respectively. Lansoprazole 30 mg once daily for 8 weeks was effective in healing erosive esophagitis. Both treatment regimens were considered safe.

Pharmacokinetics of omeprazole in healthy adults and in children with gastroesophageal reflux disease

Studies of the pharmacokinetics of omeprazole in children with gastroesophageal reflux disease (GERD) remain scarce despite the vast number of reports on its efficacy. The objectives of this study were to assess the pharmacokinetics of omeprazole in healthy adults and in children with GERD. Omeprazole (Losec, delayed-release capsules) was administered orally to 18 healthy adults (mean age 36.8 years) and 12 children with GERD (mean age 6.1 years). Blood samples were collected over 5 hours, and plasma concentrations were assessed using liquid chromatography. Population pharmacokinetic parameters were calculated using NONMEM. A 1-compartment model with zero-order absorption and a lag time was used. The population approach was well suited to the limited number of samples available, and residual variability was low. Oral clearance (CL/F) and apparent volume of distribution (V(ss)/F) in healthy adults (Mean +/- SD: 0.62 +/- 0.27 L/h/kg and 0.76 +/- 0.26 L/kg, respectively) were not significantly different than those in children with GERD (0.51 +/- 0.34 L/h/kg and 0.66 +/- 0.25 L/kg, respectively). Healthy adults displayed a statistically significantly longer delay in drug absorption (Lag time: 0.62 +/- 0.15 hours) as compared with that observed in children with GERD (0.12 +/- 0.03 hours, P < 0.05). On the basis of these findings, omeprazole dosings on a milligram-per-kilogram basis are recommended with no further adjustments for the treatment of GERD in children.

Induction of Testosterone Metabolism by Esomeprazole in aCYP2C19*2 Heterozygote

The authors describe a 42-year-old woman with previously normal sexual function who gradually developed loss of libido during treatment with esomeprazole. While taking esomeprazole, the patient's loss of libido improved with oral testosterone supplementation and deteriorated after testosterone withdrawal. There was steady improvement in both sexual function and serum free testosterone concentration after discontinuation of esomeprazole. Due to the temporal relationship between esomeprazole intake and sexual dysfunction, the authors postulate that esomeprazole causes induction of testosterone metabolism. The authors believe this to be the first case of female sexual dysfunction associated with esomeprazole described in the literature. They discuss a number of possible mechanisms for this effect.

Gastric ulcers and GERD: the new "plagues" of the 21st century update for the clinical nurse specialist

This brief overview explored the major medication therapies available for the treatment of GERD and gastric ulcers. These therapeutic agents have helped millions of people manage significant symptoms that negatively impact quality of life. A few words of caution are required when caring for the patient with GERD or ulcer disease. The CNS cannot conclude in the absence of symptoms that pathology does not exist. For each patient's plan, consider the risks and benefits of referral for diagnostic testing. Barium swallow or endoscopy may provide an invaluable benefit for diagnosis, monitoring responses to therapy, and may provide early identification of cellular abnormalities. Finally, in combination therapies (such as PPI and H2 antagonists), scheduling of doses is critical to achieve the best outcomes. Patients and families may need assistance of the CNS in designing a functional dosing schedule congruent with the demands of their lifestyles to achieve the best results.

Medical management of nocturnal symptoms of gastro-oesophageal reflux disease in the elderly

Elderly patients with nocturnal symptoms of gastro-oesophageal reflux disease (GORD) usually experience a more aggressive and complicated disease course compared with younger patients, resulting in impaired quality of life. The severity of disease and possible complications should be evaluated with upper endoscopy once the diagnosis is suspected. Elderly patients with nocturnal symptoms of GORD and evidence of endoscopic complications (oesophagitis, Barrett's oesophagus, etc.) and those with severe endoscopically negative reflux disease (ENRD) should be treated with proton pump inhibitors. Histamine H(2) receptor antagonists are suitable for mild-to-moderate ENRD. Antacids and lifestyle modifications may be incorporated into the management as adjuncts to more potent and durable therapeutic agents. Effective treatment of nocturnal GORD symptoms in the elderly will result in relief of symptoms, healing of oesophagitis and improved quality of life, and should be maintained indefinitely to prevent relapses of the disease.

Impact of cotherapy with some proton pump inhibitors on medical claims among HMO patients already using other common drugs also cleared by cytochrome P450

Adverse drug event (ADE) rates resulting from coadministration of proton pump inhibitors (PPIs) and other drugs with potential for interaction with PPIs (DPIs) are unknown. This retrospective study assesses the occurrence of such ADEs and their potential impact on medical care costs by reviewing integrated medical and pharmacy claims. Managed care patients receiving one or more DPIs were identified. Within this sample, those who were also prescribed omeprazole or lansoprazole (DPI + PPI) were included. A second cohort (DPI alone) was created, matching for age, gender, and DPI use. Rates of ADEs were followed for 6 months after entry. Among PPI users, 58% used one or more DPIs, whereas 7% of DPI subjects used a PPI. Among claims arising from ADEs occurring in more than 1% of patients, 14 occurred in the DPI + PPI group and 2 occurred in the DPI-alone cohort, respectively, a highly significant difference. Crude odds ratios for the risks of specific ADEs were significantly increased for cotherapy with a PPI and warfarin, clarithromycin, corticosteroids, carbamazepine, nifedipine, or diclofenac. After adjustment, the first three associations remained significant. Coprescription of a PPI with potentially interacting drugs was common in practice and associated with significantly increased claims for medical care.

The effect of metoclopramide on QT dynamicity: double-blind, placebo-controlled, cross-over study in healthy male volunteers

BACKGROUND

Metoclopramide, a central and peripheral dopamine type 2 receptor antagonist, has been used as an attractive and safer alternative to cisapride. However, cardiac side-effects have also been reported with this drug.

AIM

To evaluate the effects of intravenous metoclopramide administration on cardiac repolarization using QT dynamicity, a reliable indicator of arrhythmic side-effects.

METHODS

The effect of metoclopramide on cardiac repolarization was evaluated in 10 healthy male volunteers in the supine position. Metoclopramide (10 mg) or placebo was administered intravenously at random in a double-blind, cross-over manner to the participants during continuous electrocardiographic recording in the supine position. The 30-min stationary segments of the recordings before and after drug administration were used to investigate QT dynamicity.

RESULTS

Metoclopramide administration, but not placebo, resulted in steeper QT/RR slopes compared with the pre-drug values (metoclopramide: 0.037 +/- 0.004 vs. 0.064 +/- 0.012; P = 0.041; placebo: 0.045 +/- 0.006 vs. 0.050 +/- 0.004; P = 0.563). In a two-way analysis of variance model, metoclopramide administration also increased the QT variance independently (F = 6.225, P = 0.023).

CONCLUSIONS

Metoclopramide administration increases the QT/RR slope and QT variance. These findings may partly explain the underlying mechanism of ventricular arrhythmias associated with metoclopramide.

A summary of Food and Drug Administration-reported adverse events and drug interactions occurring during therapy with omeprazole, lansoprazole and pantoprazole

BACKGROUND

Pantoprazole is claimed to have a lower potential for drug interaction than other proton pump inhibitors.

AIM

To estimate the frequency of adverse events and drug interactions reported to the Food and Drug Administration in patients receiving omeprazole, lansoprazole or pantoprazole.

METHODS

The study involved a search of the Food and Drug Administration's database for adverse events and drug interactions with omeprazole, lansoprazole or pantoprazole as primary or secondary suspect drug. An estimate of the amount of drug dispensed during the adverse event collection period (from US drug launch) was obtained from the International Medical Statistics health database.

RESULTS

Of the suspected drug interactions recorded, vitamin K antagonist interactions, although rare, were the most common. The frequency of vitamin K antagonist interactions was 0.09 per million packages for omeprazole and 0.11 per million packages for lansoprazole and pantoprazole. Interactions with benzodiazepines or phenytoin were even rarer, being reported in less than 10 patients on each proton pump inhibitor.

CONCLUSION

The frequency of reported drug interactions was low for omeprazole, lansoprazole and pantoprazole and vitamin K antagonist interactions were by far the most common. These potentially important drug interactions, although rare, were no less frequent on pantoprazole than on omeprazole or lansoprazole, suggesting a class effect.

Pharmacotherapy of gastro-oesophageal reflux disease in children: focus on safety

Gastro-oesophageal reflux (GOR) disease is very common and, in the majority of infants, is physiological. However, untreated GOR disease in infants and children is associated with a decrease in quality of life for the child and their parents. It may also cause sometimes more severe complications, such as oesophagitis, and causing, in rare cases, failure to thrive, oesophageal stricture, apnoea and even death. Every therapeutic intervention (non-drug treatment, medical treatment and surgery) is associated with morbidity and even mortality. Moreover, efficacy data of many medications in children are non-existing, limited or disappointing. The safety profile of cisapride is comparable to that of other therapeutic interventions or to the risk of non-treatment. Therefore, the therapeutic approach of GOR disease in infants and children needs to be well-balanced, considering therapeutic efficacy and side effects. This review will focus on the side effects of the different therapeutic options.

Gastrointestinal promotility drugs in the critical care setting: a systematic review of the evidence

CONTEXT

Gastrointestinal promotility agents may improve tolerance to enteral nutrition, reduce gastroesophageal reflux and pulmonary aspiration, and therefore have the potential to improve outcomes of critically ill patients.

OBJECTIVE

To systematically review and critically appraise studies of promotility agents in the critical care setting.

DATA SOURCES

Computerized bibliographic search of published research (1980-2001), citation review of relevant articles, and contact with primary investigators.

STUDY SELECTION

Randomized trials of critically ill adult patients that evaluated the effect of promotility agents on measures of gastrointestinal motility were included.

DATA EXTRACTION

Relevant methods and outcome data were abstracted in duplicate by independent investigators.

DATA SYNTHESIS

We reviewed 60 citations; 18 articles met the inclusion criteria (six studies of feeding tube placement, 11 studies evaluating gastrointestinal function, and one study of clinical outcomes). The heterogeneity of study methods and outcomes measured precluded a quantitative synthesis of the data. Although there are conflicting studies, the larger and more methodologically robust studies suggest that metoclopramide has no effect on feeding tube placement. Erythromycin has been shown to increase success rates with small-bowel tube placement in two studies. Eight of ten studies evaluating the effect of cisapride, metoclopramide, or erythromycin on measures of gastrointestinal transit demonstrated positive effects; the two studies that did not were relatively small (n = 27 and 10) and likely had inadequate power to detect a difference in treatment effect. No study demonstrated a positive effect on clinical outcomes.

CONCLUSIONS

As a class of drugs, promotility agents appear to have a beneficial effect on gastrointestinal motility in critically ill patients. A one-time dose of erythromycin may facilitate small-bowel feeding tube insertion. Administration of metoclopramide appears to increase physiologic indexes of gastrointestinal transit and feeding tolerance. Concerns about safety and lack of effect on clinically important outcomes preclude strong treatment recommendations.

Options for pharmacological management of obesity in patients treated with atypical antipsychotics

Obesity is associated with considerable morbidity and decreased life expectancy. Weight gain is a commonly encountered problem associated with antipsychotic treatment. We reviewed the literature regarding the mechanisms of weight gain in response to these agents and eight substances implicated as potential obesity prevention or treatment: orlistat, sibutramine, fluoxetine, topiramate, amantadine, nizatidine and cimetidine, and metformin. Weight gain in response to antipsychotic treatment may be mediated through serotonergic, dopaminergic, adrenergic, cholinergic, histaminergic and glutaminergic receptors. Sex hormone dysregulation and altered insulin sensitivity have also been implicated. Two compounds, orlistat and sibutramine, have been shown to help prevent weight gain following a hypocaloric diet, but orlistat requires compliance with a fat-reduced diet, and sibutramine is unsuitable for patients taking serotonergic agents. The weight reducing effect of fluoxetine, even in conjunction with a hypocaloric diet, is only transient. Topiramate, amantadine and metformin may have adverse side-effects potentially outweighing the weight reducing potential. The effectiveness of cimetidine and nizatedine remains unclear. The hazards of these agents in a psychiatric population are discussed. It is concluded that the current evidence does not support the general use of pharmacological interventions for overweight patients treated with antipsychotic medication, although individually selected patients may benefit.

Kava--the unfolding story: report on a work-in-progress

This paper, originated as a submission (now updated) to the U.K. Medicines Control Agency and Committee of Safety of Medicines (CSM) on January 11, 2002, in response to a report circulated by the German Federal Institute for Drugs and Medical Products (German initials are BfArM), a compilation of which is summarized in Appendix 2. This agency issued notification in late November 2001 of some thirty adverse events associated with the use of concentrated standardized preparations of kava (Piper methysticum, Forst. f.) reported from Germany and Switzerland. An analysis of the summary of the BfArM case reports (see Appendix 2) shows that these contain duplications among the cases cited. The original submission that was sent to the CSM January 2002 has been updated to the version published here. This new version was completed in April 2002. As a result of the alert from BfArM, the evaluation of kava's safety is now occurring on a worldwide basis and, being that this a matter of considerable importance to the public, the health care community, and regulatory authorities as well as to kava farmers throughout Polynesia, it is it important to depict this progress report. As such, this updated report does not provide final answers. The material released by the BfArM is lacking in detail; however, it is hoped that this report will shed light on the kava controversy. It is anticipated that there will be further updates shortly. This report, prepared on behalf of the Traditional Medicines Evaluation Committee, a subcommittee of the European Herbal Practitioners Association, argues that many of the adverse events cited by the BfArM should not be attributed to kava. In addition, the report states that the properties of concentrated standardized kava extracts - as opposed to preparations that closely approximate those created for traditional use - contribute to causing adverse events. This report proposes a number of simple measures that will ensure that safe kava preparations may continue to be available in the United Kingdom.

Serotonin syndrome caused by selective serotonin reuptake-inhibitors-metoclopramide interaction

OBJECTIVE

To report 2 cases of serotonin syndrome with serious extrapyramidal movement disorders occurring when metoclopramide was coadministered with sertraline or venlafaxine.

CASE SUMMARY

A 72-year-old white woman was treated with sertraline for depression for 18 months and was then admitted to the hospital with a fractured tibia. She was administered metoclopramide because of nausea and, within 2 hours, developed agitation, dysarthria, diaphoresis, and a movement disorder. These symptoms recurred following 2 subsequent administrations of metoclopramide. Treatment with diazepam led to resolution of symptoms within 6 hours, and there was no recurrence at 6 weeks' follow-up. A 32-year-old white woman with major depression was treated with venlafaxine for 3 years. She was admitted following a fall and, after being given metoclopramide, developed movement disorder and a period of unresponsiveness. After a second dose of metoclopramide, these symptoms recurred and were associated with confusion, agitation, fever, diaphoresis, tachypnea, tachycardia, and hypertension. She improved with administration of diazepam, but needed repetition of this treatment over the next 16 hours. Symptoms resolved within 2 days, and she continued venlafaxine with no further adverse effects.

DISCUSSION

Both cases met Stembach's criteria for serotonin syndrome and had serious extrapyramidal movement disorders. The possible pathophysiologic mechanisms for the adverse reactions include a single-drug effect, a pharmacodynamic interaction, and a pharmacokinetic interaction. We believe that a pharmacodynamic interaction is most likely.

CONCLUSIONS

Clinicians should be aware of a risk of serotonin syndrome with serious extrapyramidal reactions in patients receiving sertraline or venlafaxine when metoclopramide is coadministered even in a single, conventional dose.