Treatment of Hypercalcemia -

<p>CALCITONIN Calcitonin acts within a few hours of its administration, principally through receptors on osteoclasts, to block bone resorption. Calcitonin, after 24 hours of use, is no longer effective in lowering calcium. Tachyphylaxis, a known phenomenon with this drug, seems to explain the results, since the drug is often effective in the first 24 hours of use. Therefore, in life-threatening hypercalcemia, calcitonin can be used effectively within the first 24 hours in combination with rehydration and saline diuresis while waiting for more sustained effects from a simultaneously administered bisphosphonate such as pamidronate. Usual doses of calcitonin are 2-8 U/kg of body weight IV, SC, or IM every 6-12 hours. OTHER THERAPIES Plicamycin (formerly mithramycin), which inhibits bone resorption, has been a useful therapeutic agent but is now seldom used because of its toxicity and the effectiveness of bisphosphonates. Plicamycin must be given IV, either as a bolus or by slow infusion; the usual dose is 25 mg/kg body weight. Gallium nitrate exes a hypocalcemic action by inhibiting bone resorption and altering the structure of bone crystals. It is not often used now because of superior alternatives(harrison 18 pg 3113)</p>