The gastric and upper-airway flora of 60 consecutive patients treated with antacids or cimetidine in a respiratory/surgical intensive-therapy unit were studied. In 52 (87.0%) patients one or more organisms were cultured simultaneously from both upper airway and stomach. A sequence of transmission was clear in 17 of these patients. Pneumonia due to gram-negative bacilli developed in 31 patients; in most cases the causative organisms were of gastric origin. No pneumonia developed in the 8 patients whose gastric and upper-airway flora were different. The number of gram-negative bacilli in gastric aspirates correlated with the pH of the gastric aspirate. Treatment of seriously ill patients with antacids or cimetidine may encourage airway colonisation and predispose the patients to pneumonia caused by gram-negative bacilli.
An antacid is a substance which neutralizes stomach acidity and is used to relieve heartburn, indigestion or an upset stomach. Some antacids have been used in the treatment of constipation and diarrhea. Marketed antacids contain salts of aluminium, calcium, magnesium, or sodium. Some preparations contain a combination of two salts, such as magnesium carbonate and aluminium hydroxide (e.g. hydrotalcite).
Antacids are available over the counter and are taken by mouth to quickly relieve occasional heartburn, the major symptom of gastroesophageal reflux disease and indigestion. Treatment with antacids alone is symptomatic and only justified for minor symptoms. Alternative uses for antacids include constipation, diarrhea, hyperphosphatemia, and urinary alkalization. Some antacids are also used as an adjunct to pancreatic enzyme replacement therapy in the treatment of pancreatic insufficiency.
Non-particulate antacids (sodium citrate) increase gastric pH with little or no effect on gastric volume, and therefore may see some limited use in pre-operative procedures. Sodium citrate should be given within 1 hour of surgery to be the most effective.
Conventional effervescent tablets contain a significant amount of sodium and are associated with increased odds of adverse cardiovascular events according to an 2013 study. Alternative sodium-free formulations containing magnesium salts may cause diarrhea, whereas those containing calcium or aluminum may cause constipation. Rarely, long-term use of calcium carbonate may cause kidney stones. Long-term use of antacids containing aluminum may increase the risk of developing osteoporosis. In vitro studies have found a potential for acid rebound to occur du