title: Effect of Helicobacter pylori infection and acid blockade by lansoprazole on clarithromycin bioavailability.
abstract: The effect of proton pump inhibitors and Helicobacter pylori infection on the bioavailability of antibiotics is poorly understood. We determined the effects of 5-day oral administration of 60 mg lansoprazole on the bioavailability of clarithromycin in individuals with and without H. pylori infection. Thirteen H. pylori-infected and 10 non-infected healthy volunteers were enrolled in a study with an open-randomized two-period crossover design and a 21-day washout period between phases. Plasma concentrations of clarithromycin in subjects with and without lansoprazole pre-treatment were measured by liquid chromatography coupled to a tandem mass spectrometer. Clarithromycin Cmax and AUC0-10 h were significantly reduced after lansoprazole administration. In addition, lansoprazole treatment of the H. pylori-positive group resulted in a statistically significant greater reduction in Cmax (40 vs 15%) and AUC0-10 h (30 vs 10%) compared to lansoprazole-treated H. pylori-negative subjects. Thus, treatment with lansoprazole for 5 days reduced bioavailability of clarithromycin, irrespective of H. pylori status. This reduction, however, was even more pronounced in H. pylori-infected individuals.
authors.affiliation: Unidade Integrada de Farmacologia e Gastroenterologia, Universidade São Francisco, Av. São Francisco de Assis 218, 12916-900 Bragança Paulista, SP, Brazil.
authors.forename: R A M
authors.initials: RA
authors.lastname: Ortiz
authors.forename: S A
authors.initials: SA
authors.lastname: Calafatti
authors.forename: L A
authors.initials: LA
authors.lastname: Moraes
authors.forename: M
authors.initials: M
authors.lastname: Deguer
authors.forename: C C
authors.initials: CC
authors.lastname: Ecclissato
authors.forename: M A M
authors.initials: MA
authors.lastname: Marchioretto
authors.forename: M L
authors.initials: ML
authors.lastname: Ribeiro
authors.forename: G
authors.initials: G
authors.lastname: Bernasconi
authors.forename: J
authors.initials: J
authors.lastname: Pedrazzoli
mesh_terms: D053799:2-Pyridinylmethylsulfinylbenzimidazoles / Q000008:administration & dosage*; D000328:Adult; D000900:Anti-Bacterial Agents / Q000493:pharmacokinetics* / Q000627:therapeutic use; D000897:Anti-Ulcer Agents / Q000008:administration & dosage*; D019540:Area Under Curve; D001682:Biological Availability; D016022:Case-Control Studies; D002851:Chromatography, High Pressure Liquid; D017291:Clarithromycin / Q000493:pharmacokinetics* / Q000627:therapeutic use; D018592:Cross-Over Studies; D004357:Drug Synergism; D016481:Helicobacter Infections / Q000188:drug therapy* / Q000378:metabolism; D016480:Helicobacter pylori; D006801:Humans; D064747:Lansoprazole; D054328:Proton Pump Inhibitors; D013997:Time Factors
chemical_list: D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D000900:Anti-Bacterial Agents; D000897:Anti-Ulcer Agents; D054328:Proton Pump Inhibitors; D064747:Lansoprazole; D017291:Clarithromycin