Chewable tab: Decreased absorption of tetracycline & Fe. May decrease absorption of orally administered digoxin or indomethacin, INH, quinolones (eg, ciprofloxacin, ofloxacin), ketoconazole. Antacid-induced changes in urine pH increase urinary excretion & decrease blood conc of salicylates eg, aspirin. Antacid-induced increases in urine pH may decrease excretion of weakly basic drugs (eg, quinidine, chlorpromazine, propranolol, diazepam) & increase excretion of weakly basic drugs (eg, phenytoin, pentobarbital, warfarin). Increased absorption of dicumarol, diazepam & pseudoephedrine. May decrease the rate of chlordiazepoxide absorption. Reduced bioavailability of bisphosphonates (eg, alendronate, etidronate, risedronate). Oral susp: May increase serum levels of quinidine. Al(OH)
3: May form complexes resulting in decreased absorption w/ tetracyclines, digoxin & vit. May prevent proper absorption of H
2-antagonists, atenolol, chloroquine, cyclines, diflunisal, digoxin, diphosphonates, ethambutol, fluoroquinolones, Na fluorine, glucocorticoids, indomethacin, INH, kayexalate, ketoconazole, lincosamides, metoprolol, neuroleptics, phenothiazines, penicillamine, propranolol, Fe salts.