Pharmacy Guidelines 2

PHARMACY GUIDELINES Adult Intravenous Phosphorus Replacement Therapy General Information: •

Reference Phosphorus Levels: Serum phosphorus: 0.87-1.45 mmol/L or 2.7-4.5 mg/dL

•

Formulary IV Phosphorus Preparations: 1 mEq of Phosphorus = 0.33 mmol Phosphorus (mg/dL) x 0.32 = Phosphorus (mmol/L) 1 mmol Phosphate = 31 mg elemental phosphorus

Phosphate Salt Sodium Phosphate Potassium Phosphate

Phosphate Content 3 mmol/mL 3 mmol/mL

Sodium Content 4 mmol/mL

Potassium Content 0 4.4 mmol/mL

Hypophosphatemia: Can be divided into mild-moderate hypophosphatemia (Serum level ≥ 0.32 mmol/L and < 0.87 [≥ 1 mg/dL and < 2.5 mg/dL]) or severe hypophosphatemia (Serum level < 0.32 mmol/L [1 mg/dL]). If physician order did not state the salt of phosphate to be used, sodium phosphate would be used as default and 0.9% sodium chloride solution would be used as the default diluent. Intravenous Phosphorus Replacement (Intermittent Infusion): Serum Phosphorus 0.32-0.87 mmol/L (Mild-Moderate) < 0.32 mmol/L (Severe)

Replacement Guidelines Phosphorus 0.16-0.32 mmol/kg over 3 hours (round off to the nearest 1.5 mmol of PO4), diluted in 100 mL of 0.9% sodium chloride. Phosphorus 0.32-0.64 mmol/kg over 3 hours (round off to the nearest 3 mmol of PO4), diluted in 100 mL of 0.9% sodium chloride. Maximum daily dose 45 mmol (doses above 30 mmol requires cardiac monitoring).

Dilution & Infusion Rate: • • • • • • • • •

Bolus doses should be administered via IV pump Bolus doses should not be infused in the same lumen as calcium or TPN. For potassium phosphate orders, central or peripheral administration must be specified. If not specified, the peripheral concentration will be dispensed. For sodium phosphate, identification of access is not required. Maximum rate of administration for both potassium and sodium phosphate is 7.5 mmol phosphorus/hr Maximum concentration of potassium phosphate for central administration is 0.3 mmol phosphorus/mL (i.e. 30 mmol of phosphorus [44 mmol of potassium] /100 mL) Maximum concentration of potassium phosphate for peripheral administration is 0.06 mmol phosphorus/mL (i.e. 15 mmol of phosphorus [22 mmol of potassium] /250 mL) Maximum concentration of sodium phosphate is 0.3 mmol phosphorus/mL (i.e. 30 mmol of phosphorus/100 mL) ICU standard Concentrations: 1. 15 mmol sodium phosphate in 100 mL 0.9% sodium chloride over 4 hours 2. 20 mmol sodium phosphate in 100 mL 0.9% sodium chloride over 4 hours 3. 30 mmol sodium phosphate in 100 mL 0.9% sodium chloride over 6 hours

Precautions: • •

Patients with renal failure: dose phosphate judiciously (or even do not give) Obese patients: calculate the dose based on ideal body weight.

• • •

Potassium or sodium overload may occur, depending on the used salt. To avoid soft tissue (metastatic) calcification with symptomatic hypocalcaemia, serum calcium multiplied by serum phosphorus (in SI units) should not exceed 5. Administer dextrose conservatively until phosphorus levels normalize. (Glucose stimulates insulin secretion, increasing phosphorus consumption for ATP-dependent processes.

Monitoring: • • • •

Serum phosphorus levels should be checked after bolus dose is given. Peak levels (12 hours after bolus) will provide closer monitoring in cases of severe hypophosphatemia. If after bolus serum level is < 0.7 mmol/L, the dose should be repeated. Monitor serum calcium, potassium, phosphorus, and magnesium daily during phosphate replacement. Among complications associated with IV phosphorus blousing; hyperphosphatemia, metastatic calcification, hypocalcaemia, hypocalcemic tetany, hypotension, and hyperkalemia.

References: 1. Guidelines for Phosphorus Replacement, King Faisal Specialist Hospital & Research Center 2. Hypophosphatemia in Adults: Potassium and Sodium Phosphate Treatment Guidelines, Kingston General Hospital, Ontario-Canada; http://www.kgh.on.ca/pharmacy/Guidelines.pdf 3. Guidelines for Phosphorus Replacement in Adults, Medical University of South Carolina Pharmacy Services: www.musc.edu/pharmacyservices/medusepol/Adult_Phosphorus_Guidelines.pdf 4. Phosphorus Administration Guidelines, Massachusetts General Hospital, Department of Pharmacy & Department of Nursing Critical Care: http://www.massgeneral.org/pharmacy/icu%20Guidelines/PHOSPHORUS_new.htm 5. Potassium and Sodium Phosphate-IV Dilution, GlobalRPh Inc. http://www.globalrph.com/calcium_dilution.htm 6. Electrolyte Replacement Protocol, Oregon Health & Science University www.ohsu.edu/medicine/residency/handouts/pharmpearls/Nephrology/ElectrolyteRe placementProtocol.pdf 7. Adult Electrolyte Replacement Protocols; www.surgicalcriticalcare.net/Guidelines/electrolyte_replacement.pdf 8. Monitored Unit Electrolyte Replacement Protocols; www.emcrit.org/misc/electrolyte_replacement.pdf 9. Electrolyte Infusion Guidelines at University of Kentucky Hospital; http://www.hosp.uky.edu/Pharmacy/formulary/criteria/electrolyte.htm