Calcitriol is a form of vitamin D which helps your body effectively absorb Calcium Carbonate and additionally supports the muscles needed to avoid falls. Calcium Carbonate and Zinc are minerals which help build and maintain bones. Risedronate is a bisphosphonate which works by suppressing the activity of osteoclasts, cells that cause destruction of bone. This strengthens the bone and minimizes the risk of fractures.                                                          Common side effects :                                                                                                                                                Headache, Increased calcium level in blood, Abdominal pain, Nausea, Rash, Urinary tract infection.