Potassium Phosphates IV

Potassium Phosphates IV is a prescription medication used to treat Hypophosphatemia.

• Potassium Phosphates IV is available under the following different brand names:

Adult and pediatric dosage

Intravenous solution

• Phosphorus content: 93mg (3mM)/mL
• Potassium content: 170mg (4.4 mEq)/mL

Hypophosphatemia

Adult dosage

• Phosphorus serum level: Less than 0.5 mg/dL: 0.5 mmol/kg IV infused over 4-6 hours
• Phosphorus serum level: 0.5-1 mg/dL: 0.25 mmol/kg IV infused over 4-6 hours 
• Prevention of hypophosphatemia (eg, in TPN): 20-40 mmol/day IV admixed in TPN is a typical dose, but adjustment according to electrolyte levels is ongoing

Pediatric dosage

• Caution should be exercised in premature neonates due to aluminum toxicity 
• Phosphorus serum level: Less than 0.5 mg/dL: 0.5 mmol/kg IV infused over 4-6 hours
• Phosphorus serum level: 0.5-1 mg/dL: 0.25 mmol/kg IV infused over 4-6 hours 

Prevention of hypophosphatemia (eg, in TPN)

• Infants/children: 0.5-2 mmol/kg/day IV
• Children weighing over 50 kg or adolescents: 10-40 mmol/day IV
• Dose adjustment according to electrolyte levels is ongoing

Dosage Considerations – Should be Given as Follows: 

• See “Dosages”.

Common side effects of Potassium Phosphates IV include:

• diarrhea, and 
• stomach pain

Serious side effects of Potassium Phosphates IV include:

• blood in urine, 
• blurred vision, 
• numbness or tingling, 
• changes in skin color, 
• chest pain or pressure, 
• confusion, 
• little or no urination, 
• lightheadedness, 
• fast, slow, pounding, or irregular heartbeat, 
• fever, 
• mood or mental changes, 
• muscle cramps, 
• nausea, 
• nervousness, 
• seizures, 
• sweating, 
• difficulty breathing, 
• tiredness, 
• weakness, 
• vomiting, and
• numbness and tingling around the mouth, fingers, or feet

Rare side effects of Potassium Phosphates IV include:

• none 

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them.  Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first

• Potassium Phosphates IV has severe interactions with the following drugs:
  • lanthanum carbonate
  • sevelamer
• Potassium Phosphates IV has serious interactions with at least 33 other drugs. 
• Potassium Phosphates IV has moderate interactions with the following drugs:
  • benazepril
  • calcium carbonate
  • calcium citrate
  • calcium gluconate
  • canagliflozin
  • captopril
  • dichlorphenamide
  • potassium citrate/citric acid
  • voclosporin
• Potassium Phosphates IV has minor interactions with no other drugs.

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drugs interactions. Therefore, before using this drug, tell your doctor or pharmacist of all the drugs you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist. Check with your physician if you have health questions or concerns.

Contraindications

• Hyperphosphatemia
• Hyperkalemia
• Hypercalcemia or significant hypocalcemia
• Severe renal impairment (eGFR less than 30 mL/min/1.73m2 and end-stage renal disease)

Effects of drug abuse

• None

Short-Term Effects

• See “What Are Side Effects Associated with Using Potassium Phosphates IV?”

Long-Term Effects

• See “What Are Side Effects Associated with Using Potassium Phosphates IV?”

Cautions

• 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
• The drug is for intravenous infusion only after dilution or admixing; maximum initial or a single dose of potassium phosphate injection in intravenous fluids to correct hypophosphatemia is phosphorus 45 mmol (potassium 71 mEq); recommended infusion rate is approximately phosphorus 6.4 mmol/hr (potassium 10 mEq/hour); continuous electrocardiographic (ECG) monitoring is recommended for higher infusion rates
• 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
• 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
• Phosphorus replacement therapy with potassium phosphates should be guided primarily by the serum inorganic phosphorus levels and the limits imposed by the accompanying potassium (K+) ion
• To avoid hyperkalemia or hyperphosphatemia, infuse IV solutions containing potassium phosphates slowly
• Caution with severe renal or adrenal insufficiency due to risk for hyperkalemia or hyperphosphatemia
• High concentrations of phosphorus may cause hypocalcemia and hypocalcemic tetany; monitor calcium levels

Pulmonary vascular precipitates

• Pulmonary vascular emboli and pulmonary distress related to precipitates in pulmonary vasculature described in patients receiving admixed products containing calcium and phosphates 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 parenteral nutrition infusion, and initiate a medical evaluation. In addition to inspection of solution; infusion set and catheter should also periodically be checked for precipitates

Hyperkalemia

• Therapy may increase the risk of hyperkalemia, including life-threatening cardiac events, especially when administered in excessive doses, undiluted, or by rapid intravenous infusion
• Patients with severe renal impairment and end-stage renal disease are at increased risk of developing life-threatening hyperkalemia when administered intravenous potassium
• 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; patients with cardiac disease may be more susceptible to effects of hyperkalemia
• Consider the amount of potassium from all sources when determining the dose of the drug and do not exceed the maximum age-appropriate recommended daily amount of potassium; in patients with moderate renal impairment (eGFR greater than 30 mL/min/1.73 m2 to less than 60 mL/min/1.73 m2), start at the low end of the dose range and monitor serum potassium, phosphorus, calcium, and magnesium concentrations
• When administering intravenous fluids to correct hypophosphatemia, check serum potassium concentration before administration; if potassium concentration is 4 mEq/dL or more, do not administer the drug and use an alternative source of phosphate
• Maximum initial or single dose in intravenous fluids to correct hypophosphatemia is phosphorus 45 mmol (potassium 71 mEq); recommended infusion rate of potassium is 10 mEq/hour; continuous electrocardiographic (ECG) monitoring is recommended for higher infusion rates of potassium

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 before administration and normalize calcium before administering therapy; monitor serum phosphorus and calcium concentrations during treatment

Aluminum toxicity

• This product contains aluminum that may be toxic; aluminum may reach toxic levels with prolonged parenteral administration if kidney function is impaired; premature neonates are at particular risk because of immature kidneys
• Preterm infants are at risk for aluminum toxicity because their kidneys are immature, and they require large amounts of calcium and phosphate solutions, which also contain aluminum
• Patients with renal impairment, including preterm infants, who receive greater than 4-5 mcg/kg/day of parenteral aluminum can accumulate aluminum to levels associated with the central nervous system and bone toxicity; tissue loading may occur at even lower rates of administration
• Exposure to aluminum from therapy is not more than 4.9 mcg/kg/day when adults weighing at least 45 kg are administered recommended maximum dosage of phosphorus (45 mmol/day) for parenteral nutrition or pediatric patients 12 years of age and older weighing at least 40 kg are administered recommended maximum dosage of phosphorus (40 mmol/day) for parenteral nutrition
• When prescribing therapy for use in parenteral nutrition solutions containing other small volume parenteral products, total daily patient exposure to aluminum from admixture should be considered and maintained at no more than 5 mcg/kg/day
• When used for parenteral nutrition not recommended in adults weighing <45 kg or pediatric patients younger than 12 years of age or weighing less than 40 kg due to risks of aluminum toxicity
• Pediatric patients 12 years of age and older weighing at least 40 kg are administered recommended maximum dosage of phosphorus (40 mmol/day) for parenteral nutrition
• Tissue accumulation may occur at even lower doses

Vein damage and thrombosis

• The drug must be diluted and administered in intravenous fluids or used as an admixture in parenteral nutrition; not for direct intravenous infusion; infusion of hypertonic solutions into a peripheral vein may result in vein irritation, vein damage, and/or thrombosis
• The primary complication of peripheral administration is venous thrombophlebitis, which manifests as pain, erythema, tenderness, or a palpable cord; remove the catheter as soon as possible and initiate appropriate medical treatment if thrombophlebitis develops
• When administered peripherally in intravenous fluids to correct hypophosphatemia, a generally recommended maximum concentration is phosphorus 6.4 mmol/100 mL (potassium 10 mEq/100 mL)
• Parenteral nutrition solutions with an osmolarity of 900 mOsm/L or greater must be infused through a central catheter

Pregnancy and Lactation

• Administration of approved recommended dose of potassium phosphate injection is not expected to cause major birth defects, miscarriage, or adverse maternal or fetal outcomes; animal reproduction studies have not been conducted with intravenous potassium phosphates
• 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

Lactation

• Phosphorus and potassium are present in human milk; administration of approved recommended dose is not expected to cause harm to the breastfed infant; there is no information on effects of potassium phosphates on milk production; developmental and health benefits of breastfeeding should be considered along with mother’s clinical need for drug and any potential adverse effects on the breastfed infant from therapy or underlying maternal condition