Metabolic consequences of reduced gastric acidity

A review of the effect on metabolism of antacids, anticholinergics and histamine H2-antagonists is given. It is stated that long-term treatment with antacids by a variety of mechanisms can cause severe metabolic complications such as the milk-alkali syndrome and phosphorus depletion. The interaction with other drugs can also be marked. There is very little known of the effect of anticholinergics on metabolism. Clinical experience has not indicated that any serious consequences will occur. The authors have investigated the effect continuous treatment with cimetidine 400 mg at night or twice daily for three years on weight, haemoglobin, plasma iron, plasma folate, plasma vitamin B12, albumin and plasma calcium. The only significant difference that occurred was a slight decrease of plasma calcium within the reference values. In conclusion it is stated that there is very little indication that the moderate and inconstant reduction of acidity over 24 hours which can be achieved by anticholinergics or twice daily administration of presently available H2-antagonists will result in metabolic consequences arising from reduced acidity. Higher doses given more frequently might give a risk for bacterial overgrowth with metabolic consequences.