[The pharmacology of biphosphonates and their use in hypercalcemia]

Bisphosphonates, derivatives of pyrophosphates are substances which block the function of osteoclasts and thus break down bone. They can be administered by the oral and i.v. route. Oral treatment is limited by poor absorption which e.g. in clodronate varies between 1 - 5%. The long half-life of bisphosphonates adsorbed on bone makes it possible to achieve the desired effect by administration once in 1 - 3 months. Bisphosphonates are considered the most effective drugs for treatment of hypercalcaemia. Their effect is, however, manifested on the second or third day and thus in case of a serious acute condition caused by hypercalcaemia it is necessary to use yet other treatment commonly recommended in hypercalcaemia.