title: Additional bedtime H2-receptor antagonist for the control of nocturnal gastric acid breakthrough.
abstract: BACKGROUND
  Nocturnal gastric acid breakthrough(NAB) is defined as intragastric pH<4 for more than one continuous hour overnight. Adding H2-receptor antagonists (H2RAs)at bedtime to high-dose proton pump inhibitors is likely to enhance nocturnal gastric pH control and decrease nocturnal gastric acid breakthrough.
  
  
  OBJECTIVE
  To assess the effectiveness of additional bedtime H2-receptor antagonists in suppressing nocturnal gastric acid breakthrough and the incidence of adverse effects.
  
  
  METHODS
  We identified eligible trials by searching The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 3, 2003), MEDLINE (1966-July 2003), EMBASE (1980-July 2003) and CINAHL (1982-July 2003). We re-ran the search on CENTRAL (The Cochrane Library Issue 2, 2004), and in MEDLINE, EMBASE and CINAHL in June 2004.
  
  
  METHODS
  All randomized controlled trials evaluating H2-receptor antagonists for the control of nocturnal gastric acid breakthrough were eligible for inclusion.
  
  
  METHODS
  We extracted data and recorded relevant information onto specially developed forms. One reviewer extracted data and a second reviewer checked data extraction. We have also double-checked data entry into RevMan. For binary outcomes, we expressed the impact of the intervention as relative risks, together with 95% confidence intervals. For scale-based outcomes, we used means and standard deviations to summarise the values in each group, provided the scale permitted sufficient values. We had intended to analyse such outcomes for the presence of skew, but the studies included were too limited to permit this.
  
  
  RESULTS
  Two randomized crossover studies including 32 participants met the inclusion criteria. Because the design, dosage and duration of the treatment were different between the studies, it was not possible to conduct meta-analysis. There is no consistent conclusion between the two included studies in evaluating H2RAs for the control of NAB.
  
  
  CONCLUSIONS
  We can conclude no implications for practice at this stage. Appropriately designed, large-scale randomized controlled trials with long-term follow-up are needed to determine the effects of additional bedtime H2RAs in suppressing nocturnal gastric acid breakthrough.
authors.forename: Tao
authors.initials: T
authors.lastname: Pan
authors.forename: Yiping
authors.initials: Y
authors.lastname: Wang
authors.forename: Zheng
authors.initials: Z
authors.lastname: Guo
authors.forename: Qiong
authors.initials: Q
authors.lastname: Wang
mesh_terms: D004334:Drug Administration Schedule; D005744:Gastric Acid / Q000378:metabolism*; D006635:Histamine H2 Antagonists / Q000008:administration & dosage*; D006801:Humans; D016032:Randomized Controlled Trials as Topic
chemical_list: D006635:Histamine H2 Antagonists