Potassium Phosphate

Potassium phosphates injection is indicated as a source of phosphorus: in intravenous fluids to correct hypophosphatemia in adults and pediatric patients when oral or enteral replacement is not possible, insufficient or contraindicated. for parenteral nutrition in adults and pediatric patients when oral or enteral nutrition is not possible, insufficient or contraindicated. Potassium Phosphates Injection is a phosphorus replacement product indicated as a source of phosphorus: in intravenous fluids to correct hypophosphatemia in adults and pediatric patients when oral or enteral replacement is not possible, insufficient or contraindicated. (1) for parenteral nutrition in adults and pediatric patients when oral or enteral nutrition is not possible, insufficient or contraindicated. (1)

Potassium phosphates injection, USP is a clear and colorless solution supplied as: phosphorus 15 mmol/5 mL (3 mmol/mL) and potassium 22 mEq/5 mL (4.4 mEq /mL) in a single- dose vial. phosphorus 45 mmol/15 mL (3 mmol/mL) and potassium 66 mEq/15 mL (4.4 mEq/mL) in a single-dose vial. Injection: phosphorus 15 mmol/5 mL (3 mmol/mL) and potassium 22 mEq/5 mL (4.4 mEq/mL) in a single-dose vial. (3) phosphorus 45 mmol/15 mL (3 mmol/mL) and potassium 66 mEq/15 mL (4.4 mEq/mL) in a single-dose vial. (3)

Potassium phosphates injection is contraindicated in patients with: hyperkalemia [see Warning and Precautions (5.3)] hyperphosphatemia [see Warning and Precautions (5.4)] hypercalcemia or significant hypocalcemia [see Warning and Precautions (5.4)] severe renal impairment (eGFR less than 30 mL/min/1.73m 2 ) or end stage renal disease [see Warning and Precautions (5.3)] hyperkalemia (4) hyperphosphatemia (4) hypercalcemia or significant hypocalcemia (4) severe renal impairment (eGFR less than 30 mL/min/1.73m 2 ) or end stage renal disease (4)

Serious Cardiac Adverse Reactions with Undiluted, Bolus, or Rapid Intravenous Administration : Administer only after dilution or admixing; do not exceed the recommended infusion rate. Continuous electrocardiographic (ECG) monitoring may be needed during infusion. (2.2, 5.1) Pulmonary Embolism due to Pulmonary Vascular Precipitates : If signs of pulmonary distress occur, stop the infusion and initiate a medical evaluation. (5.2) Hyperkalemia : Increased risk in patients with renal impairment, severe adrenal insufficiency, or treated with drugs that increase potassium. Patients with cardiac disease may be more susceptible. Do not exceed the maximum daily amount of potassium or the recommended infusion rate. Continuous ECG monitoring may be needed during infusion. (5.3, 7.1) Hyperphosphatemia and Hypocalcemia: Monitor serum phosphorus and calcium concentrations during and following infusion. (5.4) Aluminum Toxicity : Increased risk in patients with renal impairment, including preterm infants. (5.5, 8.4). Hypomagnesemia : Reported in patients with hypercalcemia and diabetic ketoacidosis. Monitor serum magnesium concentrations during treatment. (5.6) Vein Damage and Thrombosis : Infuse concentrated or hypertonic solutions through a central catheter. (2.1, 2.3, 5.7)

5.1 Serious Cardiac Adverse Reactions with Undiluted, Bolus or Rapid Intravenous Administration Intravenous administration of potassium phosphates to correct hypophosphatemia in single doses of phosphorus 50 mmol and greater and/or at rapid infusion rates (over 1 to 3 hours) in intravenous fluids has resulted in death, cardiac arrest, cardiac arrhythmia (including QT prolongation), hyperkalemia, hyperphosphatemia, and seizures [see Overdosage (10)]. In addition, inappropriate intravenous administration of undiluted or insufficiently diluted potassium phosphates as a rapid "IV push" has resulted in cardiac arrest, cardiac arrhythmias, hypotension, and death. Potassium phosphates injection is for intravenous infusion only after dilution or admixing . The maximum initial or single dose of potassium phosphates injection in intravenous fluids to correct hypophosphatemia is phosphorus 45 mmol (potassium 66 mEq). The recommended infusion rate for administration through a peripheral venous catheter is approximately phosphorus 6.8 mmol/hour (potassium 10 mEq/hour). Continuous electrocardiographic (ECG) monitoring is recommended for higher infusion rates [see Dosage and Administration (2.1, 2.2)] .

5.2 Pulmonary Embolism due to Pulmonary Vascular Precipitates Pulmonary vascular emboli and pulmonary distress related to precipitates in the pulmonary vasculature have been described in patients receiving admixed products containing calcium and phosphate or parenteral nutrition. The cause of precipitate formation has not been determined in all cases; however, in some fatal cases, pulmonary emboli occurred as a result of calcium phosphate precipitates. Precipitation has occurred following passage through an in-line filter; in vivo precipitate formation may also have occurred. If signs of pulmonary distress occur, stop the parenteral nutrition infusion and initiate a medical evaluation. In addition to inspection of the solution [see Dosage and Administration (2.3)] , the infusion set and catheter should also periodically be checked for precipitates.

5.3 Hyperkalemia Potassium phosphates injection may increase the risk of hyperkalemia, including life-threatening cardiac events, especially when administered in excessive doses, undiluted or by rapid intravenous infusion [see Warnings and Precautions (5.1)] . Patients with severe renal impairment and end stage renal disease are at increased risk of developing life-threatening hyperkalemia, when administered intravenous potassium [see Contraindications (4)] . Other patients at increased risk of hyperkalemia include those with severe adrenal insufficiency or treated concurrently with other drugs that cause or increase the risk of hyperkalemia [see Drug Interactions (7.1)] . Patients with cardiac disease may be more susceptible to the effects of hyperkalemia. Consider the amount of potassium from all sources when determining the dose of potassium phosphates injection and do not exceed the maximum age-appropriate recommended daily amount of potassium. In patients with moderate renal impairment (eGFR ≥30 mL/min/1.73 m 2 to <60 mL/min/1.73 m 2 ), start at the low end of the dose range and monitor serum potassium, phosphorus, calcium, and magnesium concentrations [see Dosage and Administration (2.2, 2.4), Use in Specific Populations (8.6)] . When administering potassium phosphates injection in intravenous fluids to correct hypophosphatemia, check the serum potassium concentration prior to administration. If the potassium concentration is 4 mEq/dL or more, do not administer potassium phosphates injection and use an alternative source of phosphorus [see Dosage and Administration (2.1)] . The maximum initial or single dose of potassium phosphates injection in intravenous fluids to correct hypophosphatemia is phosphorus 45 mmol (potassium 66 mEq). The recommended infusion rate of potassium through a peripheral venous catheter is 10 mEq/hour. Continuous electrocardiographic (ECG) monitoring is recommended for higher infusion rates of potassium [see Dosage and Administration (2.2)] .

5.4 Hyperphosphatemia and Hypocalcemia Hyperphosphatemia can occur with intravenous administration of potassium phosphates, especially in patients with renal impairment. Hyperphosphatemia can cause the formation of insoluble calcium phosphorus products with consequent hypocalcemia, neurological irritability with tetany, nephrocalcinosis with acute kidney injury and more rarely, cardiac irritability with arrhythmias. Obtain serum calcium concentrations prior to administration and normalize the calcium before administering potassium phosphates injection. Potassium phosphates injection is contraindicated in patients with hyperphosphatemia and/or hypercalcemia [see Contraindications (4)]. Monitor serum phosphorus and calcium concentrations during treatment with potassium phosphates injection [see Dosage and Administration (2.2, 2.4)] .

5.5 Aluminum Toxicity Potassium phosphates injection contains aluminum that may be toxic. Aluminum may reach toxic levels with prolonged parenteral administration in patients with renal impairment. Preterm infants are particularly at risk for aluminum toxicity because their kidneys are immature, and they require large amounts of calcium and phosphate containing solutions, which also contain aluminum. Patients with renal impairment, including preterm infants, who receive greater than 4 to 5 mcg/kg/day of parenteral aluminum can accumulate aluminum at levels associated with central nervous system and bone toxicity. Tissue loading may occur at even lower rates of administration. Exposure to aluminum from potassium phosphates injection is not more than 0.6 mcg/kg/day when patients are administered the recommended dosage [see Dosage and Administration (2.4), Description (11)] . When prescribing potassium phosphates injection for use in parenteral nutrition solutions containing other small volume parenteral products, the total daily patient exposure to aluminum from the admixture should be considered and maintained at no more than 5 mcg/kg/day [see Use in Specific Populations (8.4)].

5.6 Hypomagnesemia Intravenous infusion of phosphate has been reported to cause a decrease in serum magnesium (and calcium) concentrations when administered to patients with hypercalcemia and diabetic ketoacidosis. Monitor serum magnesium concentrations during treatment.

5.7 Vein Damage and Thrombosis Potassium phosphates injection must be diluted and administered in intravenous fluids or used as an admixture in parenteral nutrition. It is not for direct intravenous infusion. […]

The following clinically significant adverse reactions are described elsewhere in the labeling: Aluminum Toxicity [see Warnings and Precautions (5.5)] Hypomagnesemia [see Warnings and Precautions (5.6)] Vein Damage and Thrombosis [see Warnings and Precautions (5.7)] The following adverse reactions in Table 5 have been reported in clinical studies or postmarketing reports in patients receiving intravenously administered potassium phosphates. Because some of these reactions were reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. TABLE 5: Adverse Reactions Reported in Clinical Studies or Postmarketing Reports with Intravenous Potassium Phosphates System Organ Class Adverse Reactions Metabolism and Nutrition Disorders pulmonary embolism due to pulmonary vascular precipitates [see Warnings and Precautions (5.2)], hyperkalemia [see Warnings and Precautions (5.3)] , hyperphosphatemia [see Warnings and Precautions (5.4)], hypocalcemia [see Warnings and Precautions (5.5)] , hypovolemia, and osmotic diuresis Cardiac Disorders hypotension, arrhythmia, heart block, cardiac arrest, bradycardia, chest pain, ECG changes [see Warnings and Precautions (5.1)] , and edema Respiratory, Thoracic, and Mediastinal Disorders dyspnea [see Warnings and Precautions (5.2)] Renal and Urinary Disorders acute phosphate nephropathy (i.e., nephrocalcinosis with acute kidney injury), decreased urine output, and transition to chronic kidney disease [see Warnings and Precautions (5.4)] Gastrointestinal Disorders diarrhea, stomach pain Musculoskeletal and Connective Tissue Disorders weakness Nervous System Disorders confusion, lethargy, paralysis, paresthesia Adverse reactions include hyperkalemia, hyperphosphatemia, hypocalcemia, and hypomagnesemia. (6) To report SUSPECTED ADVERSE REACTIONS, contact Somerset Therapeutics, LLC at 1-800-417-9175 or the FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

Use of Other Medications that Increase Potassium : Avoid use in patients receiving such products. If use cannot be avoided, closely monitor serum potassium concentrations. (5.3, 7.1)

7.1 Other Products that Increase Serum Potassium Administration of potassium phosphates injection to patients treated concurrently or recently with products that increase serum potassium (e.g., potassium-sparing diuretics, ACE inhibitors, angiotensin II receptor antagonists, digoxin, or the immunosuppressants tacrolimus and cyclosporine) increases the risk of severe and potentially fatal hyperkalemia, in particular in the presence of other risk factors for hyperkalemia [see Warnings and Precautions (5.3)] . Avoid use of potassium phosphates injection in patients receiving such products. If use cannot be avoided, closely monitor serum potassium concentrations [see Dosage and Administration (2.2, 2.4)] .

8.1 Pregnancy Risk Summary Administration of the recommended dose of potassium phosphates injection is not expected to cause major birth defects, miscarriage, or adverse maternal or fetal outcomes. Animal reproduction studies have not been conducted with potassium phosphates injection. The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively. Clinical Considerations Disease-associated Maternal and/or Embryo-Fetal Risk Phosphorus is an essential mineral element. Parenteral supplementation with potassium phosphates should be considered if a pregnant woman's requirements cannot be fulfilled by oral or enteral intake.

8.2 Lactation Risk Summary Phosphorus and potassium are present in human milk. Administration of the recommended dose of potassium phosphates injection is not expected to cause harm to a breastfed infant. There is no information on the effects of potassium phosphates on milk production. The development and health benefits of breastfeeding should be considered along with the mother's clinical need for potassium phosphates injection and any potential adverse effects on the breastfed child from potassium phosphates injection or from underlying maternal condition.

8.4 Pediatric Use Safety and effectiveness of potassium phosphates injection have been established in pediatric patients as a source of phosphorus: in intravenous fluids to correct hypophosphatemia when oral or enteral replacement is not possible, insufficient, or contraindicated. for parenteral nutrition when oral or enteral nutrition is not possible, insufficient, or contraindicated. Because of immature renal function, preterm infants receiving prolonged parenteral nutrition treatment with potassium phosphates injection may be at higher risk of aluminum toxicity. [see Warnings and Precautions (5.6)] .

8.5 Geriatric Use In general, dose selection of potassium phosphates injection for an elderly patient should be cautious, starting at the low end of the dosing range because of the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy. It may be useful to monitor renal function during treatment [see Use in Specific Populations (8.6)] .

8.6 Renal Impairment Potassium and phosphorus are known to be substantially excreted by the kidney and the risk of adverse reactions to potassium phosphates injection may be greater in patients with impaired renal function [see Warnings and Precautions (5.3, 5.4, 5.5)] . Potassium phosphates injection is contraindicated due to the risk of hyperkalemia in patients with severe renal impairment (eGFR less than 30 mL/min/1.73 m 2 ) or end stage renal disease [see Contraindications (4)] . In patients with moderate renal impairment (eGFR ≥ 30 mL/min/1.73 m 2 to < 60 mL/min/1.73 m 2 ), start at the low end of the dosage range and monitor serum potassium, phosphorus, calcium, and magnesium concentrations [see Dosage and Administration (2.2, 2.4)].

Phosphorus in the form of organic and inorganic phosphate has a variety of biochemical functions in all organs and tissues, including critical roles in nucleic acid structure, energy storage and transfer, cell signaling, cell membrane composition and structure, acid-base balance, mineral homeostasis and bone mineralization.