title: Effect of an evening dose of regular and effervescent formulations of ranitidine or cimetidine on intragastric pH in healthy volunteers.
abstract: OBJECTIVE
  To compare the effects on intragastric acidity of a single evening dose of either standard or effervescent formulations of ranitidine (300 mg) or cimetidine (800 mg).
  
  
  METHODS
  Twelve healthy subjects were studied, using a four-period randomized cross-over design and an ambulatory intragastric pH monitoring technique. The subjects received a standard evening meal at 17.00 hours and one of the H2-receptor antagonist formulations was given at 23.00 hours.
  
  
  RESULTS
  Both effervescent formulations caused a transient rapid increase in intragastric pH, reaching a maximum at about 3 min after ingestion. After both effervescent formulations a significantly higher pH was measured during the first 45 min after ingestion (P < 0.05), compared to the regular formulations. The onset of action of the H2-receptor antagonists was similar for both formulations of ranitidine and the effervescent cimetidine, but tended to be slower for the regular cimetidine (P = 0.06). Nocturnal intragastric pH was significantly increased by all four formulations, but more effectively so by the two ranitidine formulations. The duration of action (taken as time with pH > 4) of both ranitidine formulations was longer than that of both cimetidine formulations (P < 0.002).
  
  
  CONCLUSIONS
  A single evening dose of 300 mg ranitidine produces a stronger decrease of nocturnal gastric acid secretion than 800 mg cimetidine. The effervescent formulations of both drugs offer the advantage of a rapid decrease (within minutes) of intragastric acidity, with preservation of the sustained systemic effect.
authors.affiliation: Department of Gastroenterology, University Hospital Utrecht, The Netherlands.
authors.forename: A J
authors.initials: AJ
authors.lastname: Smout
authors.forename: J H
authors.initials: JH
authors.lastname: Jonkman
authors.forename: P A
authors.initials: PA
authors.lastname: Peeters
authors.forename: H
authors.initials: H
authors.lastname: De Bruin
mesh_terms: D000293:Adolescent; D000328:Adult; D002927:Cimetidine / Q000008:administration & dosage / Q000494:pharmacology*; D018592:Cross-Over Studies; D016503:Drug Delivery Systems; D005260:Female; D005744:Gastric Acid / Q000378:metabolism*; D005745:Gastric Acidity Determination; D005753:Gastric Mucosa / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D011899:Ranitidine / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D002927:Cimetidine; D011899:Ranitidine