title: Ranitidine, 75 mg, over-the-counter dose: pharmacokinetic and pharmacodynamic effects in children with symptoms of gastro-oesophageal reflux.
abstract: BACKGROUND
  The use of over-the-counter antacids has increased in children under the age of 12 years, and has been followed by an apparent increase in the use of over-the-counter histamine-2 receptor antagonists. However, the pharmacokinetic and pharmacodynamic effects of over-the-counter histamine-2 receptor antagonists in the paediatric population are largely unknown.
  
  
  OBJECTIVE
  To evaluate the pharmacokinetics and pharmacodynamics of a single dose of the over-the-counter histamine-2 receptor antagonist, ranitidine, 75 mg, in children with symptoms of gastro-oesophageal reflux disease.
  
  
  METHODS
  Children aged between 4 and 11 years with symptoms of heartburn suspected to be due to gastro-oesophageal reflux disease were recruited at six clinical centres. Following a single dose of either oral ranitidine, 75 mg (n=19), or placebo (n=10), recording of intragastric pH and serial blood sampling were carried out for 6 h.
  
  
  RESULTS
  The estimated pharmacokinetic parameters of ranitidine, 75 mg, were as follows: the median Cmax value of 477 ng/mL occurred within a median of 2.5 h after dosing, and the median half-life was 2.0 h. The intragastric pH began to rise approximately 30 min after dosing with ranitidine to a peak of pH; 4. The pH in the ranitidine group remained higher than that in the placebo group throughout the 6-h evaluation period. Adverse events were generally mild.
  
  
  CONCLUSIONS
  Ranitidine, 75 mg, significantly increased the intragastric pH in children aged 4-11 years. The pharmacokinetic and pharmacodynamic profiles were similar to those in adults. Ranitidine, 75 mg, appears to be effective for the control of intragastric acidity for 5-6 h in children aged 4-11 years.
authors.affiliation: Pediatric Gastroenterology, Children's Hospital of Pittsburgh, Pittsburgh, PA 15213, USA. ORENSTS@CHPLINK.CHP.EDU
authors.forename: S R
authors.initials: SR
authors.lastname: Orenstein
authors.forename: J L
authors.initials: JL
authors.lastname: Blumer
authors.forename: H M
authors.initials: HM
authors.lastname: Faessel
authors.forename: J A
authors.initials: JA
authors.lastname: McGuire
authors.forename: K
authors.initials: K
authors.lastname: Fung
authors.forename: B U K
authors.initials: BU
authors.lastname: Li
authors.forename: J E
authors.initials: JE
authors.lastname: Lavine
authors.forename: J E
authors.initials: JE
authors.lastname: Grunow
authors.forename: W R
authors.initials: WR
authors.lastname: Treem
authors.forename: A A
authors.initials: AA
authors.lastname: Ciociola
mesh_terms: D000897:Anti-Ulcer Agents / Q000493:pharmacokinetics / Q000494:pharmacology / Q000627:therapeutic use; D019540:Area Under Curve; D002648:Child; D002675:Child, Preschool; D004311:Double-Blind Method; D005260:Female; D005764:Gastroesophageal Reflux / Q000188:drug therapy*; D006207:Half-Life; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D011899:Ranitidine / Q000493:pharmacokinetics / Q000494:pharmacology / Q000627:therapeutic use
chemical_list: D000897:Anti-Ulcer Agents; D011899:Ranitidine