title: A pharmacokinetic interaction study between omeprazole and the H2-receptor antagonist ranitidine.
abstract: The effect of ranitidine pretreatment on the pharmacokinetics of omeprazole was investigated in 14 male human volunteers. Omeprazole (40 mg, gastroresistant pellets) was administered to the volunteers in a two-treatment study design, either alone or after 5 days pretreatment with b.i.d. doses of 150 mg ranitidine. Plasma concentrations of omeprazole were determined over a 24-hour period following drug administration, by a validated RP-HPLC method. Pharmacokinetic parameters were calculated with compartmental and non-compartmental analysis, using the computer program Kinetica (Inna Phase). In the two periods of treatments, the mean peak plasma concentrations Cmax were 730.8 ng/ml for omeprazole alone and 802.1 ng/ml for omeprazole co-administered with ranitidine (not significant). The time taken to reach the peak, Tmax, was 1.29 h and 1.42 h, respectively (not significant). The areas under the curve (AUC0-10) were 1,453.3 ng.h/ml and 1,736.8 ng.h/ml for the two periods of treatment; thus a greater AUC was obtained after pretreatment with multiple doses of ranitidine. Our data show that the pharmacokinetics of omeprazole might be inhibited by pretreatment with ranitidine; however, the clinical relevance of this interaction still has to be confirmed.
authors.affiliation: 3rd Pediatric Clinic, University of Medicine and Pharmacy Iuliu Hatieganu Cluj-Napoca, Romania. adisl@yahoo.com
authors.forename: A
authors.initials: A
authors.lastname: Leucuta
authors.forename: L
authors.initials: L
authors.lastname: Vlase
authors.forename: D
authors.initials: D
authors.lastname: Farcau
authors.forename: M
authors.initials: M
authors.lastname: Nanulescu
mesh_terms: D000328:Adult; D000897:Anti-Ulcer Agents / Q000097:blood*; D001682:Biological Availability; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004347:Drug Interactions; D006635:Histamine H2 Antagonists / Q000494:pharmacology*; D006801:Humans; D008297:Male; D009853:Omeprazole / Q000097:blood*; D011899:Ranitidine / Q000494:pharmacology*
chemical_list: D000897:Anti-Ulcer Agents; D006635:Histamine H2 Antagonists; D011899:Ranitidine; D009853:Omeprazole