Adult Aluminum Hydroxide - pharmacology Antacids - pharmacology Aspergillus - growth & development Bacteria - growth & development Candida - growth & development Cimetidine - pharmacology Double-Blind Method Drug Combinations - pharmacology Fasting Guanidines - pharmacology Humans Hydrogen-Ion Concentration Lactobacillus - growth & development Magnesium - pharmacology Magnesium Hydroxide - pharmacology Male Neisseria - growth & development Silicones - pharmacology Simethicone - pharmacology Stomach - microbiology Streptococcus - growth & development
The effect of a standard regimen of cimetidine on the gastric flora of 20 male volunteers was studied in a double-blind manner and compared with the effects of a standard antacid regimen. Postprandial microbial titers in gastric aspirates were significantly higher at 4, 8, and 16 weeks of therapy in subjects taking antacids and at 4 weeks in subjects taking cimetidine when compared with their pretreatment titers. Although not significant, there was a tendency for fasting microbial titers to be higher in subjects receiving cimetidine as compared with pretreatment titers. The higher titers were primarily related to increases in survival of mouth flora (viridans streptococci and Neisseria spp.); Enterobacteriaceae and other nitrate-reducing organisms were unusual isolates. There was no significant difference in the total titers or types of organisms isolated when subjects taking cimetidine were compared with those taking antacid.