warnings and cautions
5 WARNINGS AND PRECAUTIONS Hypercalcemia : Can occur during treatment with paricalcitol and can lead to cardiac arrhythmias and seizures. Severe hypercalcemia may require emergency attention. The risk may be increased when paricalcitol is used concomitantly with high dose calcium preparations, thiazide diuretics, or vitamin D compounds. Inform patients about symptoms of hypercalcemia and monitor serum calcium prior to initiation and during treatment and adjust dose accordingly ( 2 , 5.1 ). Digitalis toxicity : Risk increases with hypercalcemia. In patients using digitalis compounds, monitor both serum calcium and patients for signs and symptoms of digitalis toxicity. Monitor more frequently when initiating or adjusting the dose of paricalcitol ( 5.2 ). Adynamic Bone Disease : May develop and increase risk of fractures if intact PTH levels are suppressed to abnormally low levels. Monitor intact PTH levels and adjust dose if needed ( 5.3 ). 5.1 Hypercalcemia Hypercalcemia may occur during paricalcitol treatment. Acute hypercalcemia may increase the risk of cardiac arrhythmias and seizures and may potentiate the effect of digitalis on the heart [see Warnings and Precautions (5.2) ] . Chronic hypercalcemia can lead to generalized vascular calcification and other soft-tissue calcification. Severe hypercalcemia may require emergency attention. Hypercalcemia may be exacerbated by concomitant administration of high doses of calcium-containing preparations, thiazide diuretics, or other vitamin D compounds [see Drug Interactions (7) ]. In addition, high intake of calcium and phosphate concomitantly with vitamin D compounds may lead to hypercalciuria and hyperphosphatemia. Patients with a history of hypercalcemia prior to initiating therapy may be at increased risk for development of hypercalcemia with paricalcitol. In these circumstances, frequent serum calcium monitoring and paricalcitol dose adjustments may be required. When initiating paricalcitol or adjusting paricalcitol dose, measure serum calcium frequently (e.g., twice weekly). Once a maintenance dose has been established, measure serum calcium at least monthly . If hypercalcemia occurs, reduce the dose or discontinue paricalcitol until serum calcium is normal [see Dosage and Administration (2.2 , 2.3) ] . Inform patients about the symptoms of elevated calcium (feeling tired, difficulty thinking clearly, loss of appetite, nausea, vomiting, constipation, increased thirst, increased urination and weight loss) and instruct them to report new or worsening symptoms when they occur. 5.2 Digitalis Toxicity Paricalcitol can cause hypercalcemia [see Warnings and Precautions (5.1) ] which increases the risk of digitalis toxicity. In patients using paricalcitol concomitantly with digitalis compounds, monitor serum calcium and patients for signs and symptoms of digitalis toxicity. Increase the frequency of monitoring when initiating or adjusting the dose of paricalcitol [see Drug Interactions (7) ] . 5.3 Adynamic Bone Disease Adynamic bone disease with subsequent increased risk of fractures may develop if intact PTH levels are suppressed by paricalcitol to abnormally low levels. Monitor intact PTH levels to avoid over suppression and adjust paricalcitol dose, if needed [see Dosage and Administration (2.2 , 2.3) ] .