Prevacid
Intragastric acidification reduces the occurrence of false-negative urea breath test results in patients taking a proton pump inhibitor.

Chey WD, Chathadi KV, Montague J, Ahmed F, Murthy U.

University of Michigan Health System, Ann Arbor, USA.

OBJECTIVE: The aim of this study was to investigate whether reducing intragastric pH, at the time of urea ingestion, decreases the likelihood of false-negative (FN) urea breath test (UBT) results in patients taking a proton pump inhibitor (PPI). METHODS: Patients with active Helicobacter pylori infection underwent a baseline 14C-UBT (UBT-1) followed by treatment with lansoprazole 30 mg/day for 14 to 16 days. On day 13, patients returned for a repeat standard UBT (UBT-2). Between days 14 to 16, patients underwent a modified UBT (UBT-3), which included consuming 200 ml of 0.1 N citrate solution 30 min before and at the time of 14C-urea administration. Breath samples were collected 10 and 15 min after 14C-urea ingestion. Mean 14CO2 excretion and the number of FN and equivocal UBT results were compared for the three UBTs. RESULTS: A total of 20 patients completed the study. Lansoprazole caused a significant decrease in mean breath 14CO2 excretion (disintegrations per minute) between UBT-1 (2.96 +/- 0.23) and UBT-2 (2.08 +/- 0.52, p < 0.05). Lansoprazole caused six (30%) FN and eight (40%) equivocal UBT-2 results. Mean breath 14CO2 excretion for UBT-3 (677 +/- 514) was greater than for UBT-2 (234 +/- 327, p = 0.001). UBT-3 caused only two (10%) FN and three (15%) equivocal results. The 15-min breath sample caused fewer FN and equivocal results than the 10-min sample for both UBT-2 and UBT-3. CONCLUSIONS: Giving citrate before and at the time of 14C-urea administration increases mean breath 14CO2 excretion and decreases FN and equivocal UBT results in patients taking a PPI. These observations suggest that it may be possible to design a UBT protocol that will remain accurate in the face of PPI therapy.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11316142&dopt=Abstract lansoprazole Prevacid



Prevacid
Proton pump inhibitors: a study of GPs' prescribing.

Jones MI, Greenfield SM, Jowett S, Bradley CP, Seal R.

Department of Primary Care and General Practice, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.

BACKGROUND: There has been a rapid increase in proton pump inhibitor (PPI) prescribing in recent years, and controlling the cost and improving the quality of prescribing is an issue of concern to many GPS: OBJECTIVE: Our aim was to compare GPs' usage of different PPIs and explore how GPs' PPI prescribing changes following the introduction of a cheaper competitor. METHODS: PPI prescribing data (PACT) for 53 GPs, who were selected as regular users of a teaching hospital, were monitored from January 1995 to December 1997. The GPs were located in two adjoining health districts and had been interviewed about influences on their decisions to begin prescribing lansoprazole. The PPI prescribing data were collected for the teaching hospital and the general hospital in the adjoining district. RESULTS: Complete prescribing data were available for 50 GPS: Total PPI prescribing increased throughout the study due mainly to increasing use of the new PPIS: Use of the new PPIs increased from 6 to 24% over 3 years. The proportion of maintenance doses prescribed increased from 3 to 12%. There was a 23-fold difference in total PPI prescribing and an 87-fold difference in lansoprazole prescribing between the highest and lowest prescribers. The uptake of pantoprazole was slower than that of lansoprazole. A rapid increase in the use of lansoprazole by the GPs followed an increase in use in the teaching hospital. CONCLUSION: Hospital prescribing was an important influence on the choice of PPI used by GPS: The wide variation in PPI prescribing suggests that there is scope for improvement in the quality and cost of PPI prescribing.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11356744&dopt=Abstract lansoprazole Prevacid



Prevacid
High-performance liquid chromatographic assay for the simultaneous determination of lansoprazole enantiomers and metabolites in human liver microsomes.

Katsuki H, Hamada A, Nakamura C, Arimori K, Nakano M.

Department of Pharmacy, Kumamoto University Hospital, Japan.

In this study, a simple, sensitive and enantioselective HPLC method was developed for the simultaneous determination of lansoprazole enantiomers: a proton pump inhibitor, and its major metabolites: 5-hydroxylansoprazole and lansoprazole sulfone in human liver microsomes. After extraction from the microsomal incubation mixture with a diethyl etherdichloromethane (7:3, v/v) mixture, analytes were measured by reversed-phase HPLC on a Chiralcel OD-R column. Detection was made using an ultraviolet absorbance detector set at a wavelength of 285 nm. The mobile phase consisted of a methanol-water (75:25, v/v) mixture. At a flow-rate of 0.5 ml/min, the total run time was 35 min. The limit of quantification for both lansoprazole enantiomers was 0.25 microM and for the metabolites 0.13 microM. The method is suitable for the analysis of lansoprazole enantiomers and its metabolites from human microsomal liver incubations.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11419737&dopt=Abstract lansoprazole Prevacid



Prevacid
Factors associated with non-response in proton pump inhibitor users: a study of lansoprazole therapy.

Claessens AA, Heerdink ER, Lamers CB, van Eijk JT, Leufkens HG.

Department of Pharmacoepidemiology and Pharmacotherapy, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht, The Netherlands.

BACKGROUND: Proton pump inhibitors (PPI) demonstrate high healing rates of 85-98% in clinical trials. Due to the limited knowledge regarding response and non-response to lansoprazole in daily practice and for the reason that resistance to PPIs is scarce, we investigated factors possibly associated with non-response. METHODS: Data were used from a prospective, open label, observational follow-up study in which 10,008 lansoprazole users were followed over time. The study was designed according to the SAMM guidelines. A matched nested case-control design was used to compare non-responding (cases) and responding (controls) lansoprazole users. Non-response was defined as worsening or non-improvement of symptoms at the first evaluation after at least 8 weeks of use, response as disappearance or improvement of symptoms within 8 weeks of use. Controls were matched for the evaluating physician. RESULTS: A total of 186 non-responders and 372 responders to PPI treatment were identified as cases and controls. Age of over 60 years, heavy smoking and previous use of PPIs were significantly more common in non-responding patients compared with responding patients. There were no differences found between the reported diagnosis regarding response. CONCLUSION: In daily clinical practice, previous use of PPIs, heavy smoking and an age > 60 years were significantly associated with non-response to treatment with lansoprazole. Previous use of PPIs in non-responding patients might suggest resistance to PPIs. The knowledge that non-response drives non-response may encourage physicians to follow PPI users with previous PPI use more closely.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11468874&dopt=Abstract lansoprazole Prevacid



Prevacid
Laparoscopic fundoplication versus lansoprazole for gastro-oesophageal reflux disease. A pH-metric comparison.

Frazzoni M, Grisendi A, Lanzani A, Melotti G, De Micheli E.

Department of Internal Medicine and Gastroenterology, S. Agostino Hospital, Modena, Italy. marziofrazzoni hotmail.com

BACKGROUND: Treatment strategies that abolish abnormal reflux could prevent long-term complications of gastro-oesophageal reflux disease. AIMS: To compare the efficacy of laparoscopic fundoplication and lansoprazole in abolishing abnormal reflux in patients with gastro-oesophageal reflux disease. PATIENTS: Study population comprised 130 patients referred for possible antireflux surgery and with heartburn as the dominant symptom. METHODS: After oesophageal manometric and pH-metric evaluation and detailed information 55 patients asked to undergo laparoscopic antireflux surgery while 75 chose a medical treatment regimen based on lansoprazole. Treatment efficacy was assessed by ambulatory oesophageal pH-monitoring. RESULTS: All 55 patients who underwent fundoplication became free of heartburn: oesophageal pH-monitoring gave normal results in 85%. In patients treated with lansoprazole, at individualized daily dosages titrated to abolish both heartburn and abnormal acid reflux, normal pH-metric results were obtained in 96% of cases (p<0.05 vs surgically treated patients). CONCLUSIONS: Lansoprazole at individualized dosages was significantly more effective than laparoscopic fundoplication, in the short-term, in abolishing abnormal reflux in gastro-oesophageal reflux disease patients.

Online source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11926567&dopt=Abstract lansoprazole Prevacid