Calxim Tablet is Calcium citrate, Calcitriol, Zinc & magnesium oxide tablets. Calcium can also bind to other minerals (such as phosphate) and aid in their removal from the body. Calcium citrate is used to prevent and to treat calcium deficiencies. Calcium can make it harder for your body to absorb certain medicines. Calcium citrate works best if you take it with food. Calcitriol is given to prevent or treat low levels of calcium in people with kidney or parathyroid gland problems. Zinc is a naturally occurring mineral. Zinc is important for growth and for the development and health of body tissues. Zinc sulfate is used to treat and to prevent zinc deficiency. Magnesium oxide is a mineral supplement used to treat or prevent low levels of magnesium in the blood. Magnesium is important for many systems in the body, but it is especially vital for healthy muscles and bones. Some people use magnesium oxide to relieve heartburn or indigestion.