Systematic review: Impaired drug absorption related to the co-administration of antisecretory therapy

Background Due to suppression of gastric acidity during antisecretory therapy, an impaired absorption of co-administered drugs may occur. Aim To review evidence of impaired drug absorption related to the use of co-administered PPIs or H 2RAs. Methods Systematic search of MEDLINE/EMBASE/SCOPUS databases (1980-September 2008) for English articles with keywords: drug malabsorption and absorption, stomach, anti-secretory / acid inhibitory drugs, histamine H 2 antagonists, PPIs, gastric acid, pH, hypochlorhydria, gastric hypoacidity. From 2126 retrieved articles, 16 randomized crossover studies were identified investigating impaired absorption of nine different drugs in association with co-administration of PPIs or H 2RAs. Information on investigated drug, study type, features of investigated subjects, study design, type of intervention, and study results were extracted. Results The identified studies investigated the absorption kinetics of nine drugs. Acid suppression reduced absorption of ketoconazole, itraconazole, atazanavir, cefpodoxime, enoxacin and dipyridamole (median C max reduction by 66.5%). An increased absorption of nifedipine and digoxin (median AUC increase by 10%) and a 2-fold-increase in alendronate bioavailability were observed. Conclusions Gastric pH appears relevant for absorption of some cardiovascular or infectious disease agents. Antisecretory treatment may significantly modify the absorption of co-administered drugs. © 2009 Blackwell Publishing Ltd.