COMPOUNDS CONTAINING CALCIUM,IRON,MAGNESIUM SALTS, ANTACIDS, AND FOOD,SOME OSMOTIC LAXATIVES INTERFERE WITH ABSORPTION OF ALENDRONATE. NSAID IF GIVEN WITH IT MAY INCREASE THE INCIDENCE OF G.I. SIDE EFFECTS AND RENAL SIDE EFFECTS. RANITIDINE DOUBLES THE BIOAVAILABILITY OF ALENDRONATE.