Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

Some products that may interact with this drug are: digoxin, cellulose sodium phosphate, certain phosphate binders (such as calcium acetate).

Calcium can decrease the absorption of other drugs such as bisphosphonates (for example, alendronate), tetracycline antibiotics (such as doxycycline, minocycline), estramustine, levothyroxine, and quinolone antibiotics (such as ciprofloxacin, levofloxacin). Separate your doses of these medications as far as possible from your doses of calcium. Ask your doctor or pharmacist about how long you should wait between doses and for help finding a dosing schedule that will work with all your medications.

Check the labels on all your prescription and nonprescription/herbal products (such as antacids, vitamins) because they may contain calcium. Ask your pharmacist about using those products safely.