Hypophosphatemia Medication

Updated: Jan 23, 2018
  • Author: Eleanor Lederer, MD, FASN; Chief Editor: Vecihi Batuman, MD, FASN  more...
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Medication

Medication Summary

The goals of pharmacotherapy are to increase serum phosphate levels, to reduce morbidity, and to prevent complications.

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Mineral supplements

Class Summary

Phosphate salts are used to increase serum phosphate levels. Phosphorus is involved in many biochemical functions in the body and significant metabolic and enzyme reactions in almost all organs and tissues; it exerts a modifying influence on the steady state of calcium levels, a buffering effect on acid-base equilibrium, and a primary role in the renal excretion of hydrogen ion. For severe hypophosphatemia (< 1 mg/dL), use parenteral preparations of phosphate for repletion. IV preparations are available as sodium or potassium phosphate. Response to IV serum phosphorus supplementation is highly variable and can be associated with hyperphosphatemia and hypocalcemia. Infusion rate and choice of initial dosage is based on severity of hypophosphatemia and presence of symptoms. Closely monitor serum phosphate and calcium levels. For less severe hypophosphatemia (1-2 mg/dL), PO phosphate salt preparations can be used.

Potassium acid phosphate (Neutra-Phos-K)

PO preparations are available as sodium or potassium phosphate in cap or liquid form. Neutra-Phos packets contain 250 mg of phosphorus/packet. Tabs contain 250, 125.6, or 114 mg apiece. Liquid preparations are available as 250 mg/75 mL.

Potassium phosphates, IV

Contains 3 mmol/mL of phosphorus and 4.4 mEq/mL of potassium.

Sodium phosphates, IV

Contains 3 mmol/mL of phosphorus and 4 mEq/mL of sodium.

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Vitamin D preparations

Class Summary

Vitamin D enhances intestinal and renal absorption of phosphate. Can be administered in addition to phosphate supplements to increase serum phosphate and total body phosphate stores.

Ergocalciferol (vitamin D-2)

Requires conversion to active 1,25 dihydroxy cholecalciferol in kidneys. Administered PO.

Calcitriol (Calcijex, Rocaltrol)

Active form of vitamin D, 1,25 dihydroxyvitamin D-3. Use in patients with renal failure who are unable to convert inactive prohormone forms to active metabolite. Available in PO and parenteral form.

Doxercalciferol (Hectorol)

Requires hydroxylation in liver to be converted to an active vitamin D metabolite. May cause less toxicity than calcitriol with regard to calcium homeostasis. Predominantly used to treat secondary hyperparathyroidism of renal failure

Paricalcitol (Zemplar)

Vitamin D-3 analogue available in parenteral form and predominantly used to treat secondary hyperparathyroidism of renal failure, especially when calcitriol treatment has resulted in hypercalcemia. Appears to have a lesser effect on calcium and phosphorus metabolism than calcitriol. For this reason, it is not as useful as calcitriol for the treatment of hypophosphatemia.

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Calcimimetic drugs

Class Summary

This category of drug activates the calcium sensing receptor on parathyroid gland cells, thus diminishing the release of parathyroid hormone. These agents are useful for the control of hyperparathyroidism in patients who are unwilling to undergo surgery or who are suboptimal candidates for surgery.

Cinacalcet (Sensipar)

This drug is available in oral form and has to be taken daily for desired effect. To monitor efficacy, the drug should be taken at the same time every day and the intact parathyroid hormone (iPTH) level should also be taken at the same time every time it is checked. The clinician needs to monitor also for the development of hypocalcemia.

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