title: Antihypertensive drugs and the risk of gastrointestinal bleeding.
abstract: OBJECTIVE
  Calcium channel blockers have been reported to increase the risk of gastrointestinal bleeding. We tested this hypothesis, and also assessed whether beta blockers decrease this risk.
  
  
  METHODS
  A nested case-control design within a population-based cohort of all 34,074 new users of beta blockers, angiotensin-converting enzyme (ACE) inhibitors, or calcium channel blockers in Saskatchewan, from 1990 to 1993 and followed up to March 1995, was used. We identified all 311 subjects hospitalized because of gastrointestinal bleeding during this period, each of whom was matched to 10 randomly selected controls.
  
  
  RESULTS
  The rate of hospitalization for gastrointestinal bleeding was 3.0 per 1,000 per year. The adjusted rate ratio of gastrointestinal bleeding for current use of calcium channel blockers was 1.1 (95% confidence interval [CI] 0.8 to 1.4) and 0.66 (95% CI 0.44 to 0.98) for beta blockers compared with no current use of anti-hypertensive drugs. The adjusted rate ratio for ACE inhibitor use was 1.0 (95% CI 0.7 to 1.3) while that for diuretic use was 1.4 (95% CI 1.0 to 2.0).
  
  
  CONCLUSIONS
  The use of calcium channel blockers does not appear to increase the risk of gastrointestinal bleeding in the first five years of treatment, while beta blockers may prevent this adverse event. The unexpected elevated risk associated with the use of diuretics needs to be investigated further.
authors.affiliation: Department of Epidemiology and Biostatistics, McGill University, the Royal Victoria Hospital, Montreal, Québec, Canada.
authors.forename: S
authors.initials: S
authors.lastname: Suissa
authors.forename: C
authors.initials: C
authors.lastname: Bourgault
authors.forename: A
authors.initials: A
authors.lastname: Barkun
authors.forename: O
authors.initials: O
authors.lastname: Sheehy
authors.forename: P
authors.initials: P
authors.lastname: Ernst
mesh_terms: D000328:Adult; D000368:Aged; D000959:Antihypertensive Agents / Q000009:adverse effects*; D002121:Calcium Channel Blockers / Q000009:adverse effects*; D016022:Case-Control Studies; D005260:Female; D006471:Gastrointestinal Hemorrhage / Q000139:chemically induced*; D006760:Hospitalization; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D012306:Risk
chemical_list: D000959:Antihypertensive Agents; D002121:Calcium Channel Blockers