Ranitidine, 75 mg, over-the-counter dose: pharmacokinetic and pharmacodynamic effects in children with symptoms of gastro-oesophageal reflux.

Author(s): Orenstein SR, Blumer JL, Faessel HM, McGuire JA, Fung K, Li BU, Lavine JE, Grunow JE, Treem WR, Ciociola AA

Affiliation(s): Pediatric Gastroenterology, Children's Hospital of Pittsburgh, Pittsburgh, PA 15213, USA. ORENSTS@CHPLINK.CHP.EDU

Publication date & source: 2002-05, Aliment Pharmacol Ther., 16(5):899-907.

Publication type: Clinical Trial; Multicenter Study; Randomized Controlled Trial

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. AIM: 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.