For long-term use, avoid calcium derived from dolomite, bonemeal, fossil or oyster shells as it contains larger amounts of lead. Hypercalcemia secondary to calcium supplementation in patients taking digoxin may precipitate dysrhythmias. Space administration of calcium-containing products and etidronate by 2 h. Calcium may decrease the absorption of iron by increasing intragastric pH. If used concurrently, stagger their administration.
Calcium impairs the absorption of quinolones.
If used concurrently, space administration by 2 h.