Decreased therapeutic effect of chlorpropamide, lithium, salicylates & tetracyclines. Increase therapeutic effect of amphetamines & ephedrine/pseudoephedrine. May result in systemic alkalosis w/ antacids. May promote the development of Ca stones & hypernatremia w/ antacids. Increased Al absorption w/ antacids. Reduced solubility of ciprofloxacin, norfloxacin or ofloxacin in the urine. Additive effect w/ laxatives.