Fluids, Electrolytes, Acid-Base Disorders, and Nutrition Support

Hyperphosphatemia

Definition: Serum phosphorus concentration greater than 5 mg/dL, usually not clinically relevant

until serum phosphorus is greater than 6 mg/dL

Signs and symptoms: Hypocalcemia and metastatic calcification (e.g., neuromuscular irritability,

prolonged QT interval, tetany) – Usually does not occur until the serum calcium-phosphorus

product approaches 55 mg/dL or greater (Adv Exp Med Biol 1978;103:195-201).

Etiologies:

Renal failure

ii.

Immobility

iii.

Chronic critical illness–associated metabolic bone disease

iv.

Excessive phosphorus intake

Vitamin D toxicity

vi.

Tumor lysis syndrome

vii.

Hypoparathyroidism

Reduce phosphorus intake (omit from PN solution, with or without reduction of ILE content of

PN solution if a high-fat formulation [controversial as phosphorus in organic form: phospholipids

and not inorganic such as sodium phosphate]; change to “low- or no-electrolyte” renal enteral

formula).

ii.

2005;62:2355-61). Dosing should be timed with meals for patients consuming oral diets or

given at regular intervals before and/or during enteral nutrition administration for patients on

EN.

Drug

Available Strength

Phosphorus-Binding

Capacity

Recommended Empiric

Initial Dose

Calcium carbonatea

500, 750, 1000 mg per tablet

Calcium 43 mg/g

1 g QID

Calcium acetatea

667 mg per tablet

Calcium 106 mg/g

1334–2001 mg TID

Sevelamerb

400 mg, 800 mg per tablet; 800

mg or 2400 mg per packet (for

oral suspension)

Sevelamer 80 mg/g

800–1600 mg TID

Lanthanumc

500, 750, 1000 mg per tablet or

packet

Lanthanum 78–156 mg/g

500 mg TID

Ferric citrated

210 mg per tablet

Iron 84.8-87.9 mg per

gram and Citrate 19.1-19.8

mg per gram

420 mg TID

Sucroferric

oxyhydroxided

500 mg per tablet

Sucroferric 260 mg per

gram

500 mg TID

aDo not use if the patient is hypercalcemic.

bSevelamer carbonate comes in a powder for suspension; easier for administering to patients receiving EN; less likely to worsen metabolic acidosis than tablet in patients

with renal failure because tablet is in hydrochloric acid salt form.

c750 and 1000 mg available as oral packet; 500, 750, and 1000 mg available as chewable tablet.

dMay increase iron concentrations.

EN = oral/enteral nutrition; QID = four times daily; TID = three times daily.