<p>Calcium can decrease absorption of the following drugs when taken together: biphosphonates (e.g., alendronate), quinolone antibiotics (e.g., ciprofloxacin, levofloxacin), and tetracycline antibiotics (e.g., doxycycline, minocycline), levothyroxine, phenytoin (an anticonvulsant), and tiludronate disodium (to treat Paget&#39;s disease). Thiazide-type diuretics can interact with Calcium supplements, increasing the risks of hypercalcemia and hypercalciuria. Both aluminum- and magnesium-containing antacids increase urinary calcium excretion. Mineral oil and stimulant laxatives decrease calcium absorption. Glucocorticoids, such as prednisone, can cause calcium depletion and eventually osteoporosis when they are used for months. Oral contraceptives as well as estrogen compounds reduce calcium. Anti-inflammatories such as NSAIDs, Aspirin, Ibuprofen deplete calcium. Corticosteroids deplete calcium.</p>