title: Influence of single and multiple doses of oral ranitidine on the gastric transit of an indigestible capsule in humans.
abstract: The effect of single and multiple doses of ranitidine on the gastric residence time of an indigestible pH-sensitive radiotelemetric device, the Heidelberg capsule, was evaluated in 12 healthy men (mean age, 29 +/- 8 years) in a placebo-controlled, randomized, crossover study. Each subject received 150 mg ranitidine or placebo orally 2 hours before administration of the Heidelberg capsule. A 500 kcal standardized breakfast was served 1/2 hour before the capsule was administered. Gastric pH was monitored at 15-minute intervals, until pyloric passage (pH increase greater than or equal to 3 U) of the Heidelberg capsule was observed. Blood samples (n = 12) were collected 0 to 8 hours after administration of drug or placebo. The subjects continued to receive ranitidine or placebo b.i.d. for 7 days and returned on day 8 for a similar evaluation. After a 1-week washout period, the subjects received the alternative treatment. The mean (+/- SD) gastric residence time of the Heidelberg capsule was significantly decreased after both single and multiple doses of ranitidine compared to placebo (3.1 +/- 0.9 versus 3.8 +/- 1.1 hours, p less than 0.02; and 2.9 +/- 0.74 versus 3.9 +/- 0.9 hours, p less than 0.005, n = 9). Gastric residence time was not determined in three subjects who showed unusually slow gastrointestinal motility after both placebo and ranitidine. Mean AUC(0-8 hr) and AUC(0-infinity) were significantly increased, whereas Cmax, tmax, and t1/2 remained unchanged after 7 days of ranitidine b.i.d. treatment. No ranitidine double-peak profile or linear pharmacokinetic-pharmacodynamic relationship was identified.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Clinical Pharmacology, Jefferson Medical College of Thomas Jefferson University, Philadelphia.
authors.forename: P
authors.initials: P
authors.lastname: Mojaverian
authors.forename: P H
authors.initials: PH
authors.lastname: Vlasses
authors.forename: S
authors.initials: S
authors.lastname: Parker
authors.forename: C
authors.initials: C
authors.lastname: Warner
mesh_terms: D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D002214:Capsules; D004311:Double-Blind Method; D005746:Gastric Emptying / Q000187:drug effects*; D005772:Gastrointestinal Transit / Q000187:drug effects*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008875:Middle Aged; D016032:Randomized Controlled Trials as Topic; D011899:Ranitidine / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000494:pharmacology*; D013270:Stomach / Q000187:drug effects
chemical_list: D002214:Capsules; D011899:Ranitidine