Uses : It is used for the treatment and prevention of low calcium levels and resulting bone conditions including osteoporosis (weak bones due to low bone density), rickets (a condition in children involving softening of the bones), and osteomalacia (a softening of bones involving pain) and to treat the low level of Vitamin- D . Side Effects : Constipation, diarrhea or upset stomach may occur. These effects are usually temporary and may disappear as your body adjusts to this medication. If any of these effects persist or worsen, contact your doctor or pharmacist promptly.When not to use : It is contraindicated in patients with known hypersensitivity to the drug.