potassium phosphate injection

Potassium phosphate

Potassium phosphate injection is a phosphate supplement that is used to treat or prevent hypophosphatemia (low phosphorus in the blood). Potassium phosphate is sometimes added to intravenous (IV) fluids given to people who cannot eat or drink anything.

Phosphorus is a naturally occurring substance that is important in every cell of the body. Phosphorous is contained in all body cells and is used for growth and repair of cells and tissues.

Potassium phosphate is to be given only by or under the direct supervision of a doctor.

Potassium phosphate must be mixed with a liquid (diluent) before using it. If you are using the injections at home, be sure you understand how to properly mix and store the medicine.

Potassium phosphate must be given slowly.

While using this medicine, you may need frequent blood or urine tests.

Potassium phosphate is available in the following dosage forms: Solution

What should I avoid while taking potassium phosphate?

Ask your doctor before using an antacid, and use only the type your doctor recommends. Some antacids can make it harder for your body to absorb potassium phosphate and sodium phosphate.

Avoid taking a vitamin or mineral supplement that contains calcium or vitamin D, unless your doctor tells you to.

Do not use potassium supplements or salt substitutes while you are taking potassium phosphate and sodium phosphate, unless your doctor has told you to.

Phosphorus

Phosphorus, an essential mineral, is naturally present in many foods and available as a dietary supplement. Phosphorous is contained in all body cells, phosphorus is a component of bones, teeth, DNA, and RNA 1). In the form of phospholipids, phosphorus is also a component of cell membrane structure and of the body’s key energy source, ATP. Many proteins and sugars in the body are phosphorylated. In addition, phosphorus plays key roles in regulation of gene transcription, activation of enzymes, maintenance of normal pH in extracellular fluid, and intracellular energy storage. In humans, phosphorus makes up about 1 to 1.4% of fat-free mass. Of this amount, 85% is in bones and teeth, and the other 15% is distributed throughout the blood and soft tissues 2).

Many different types of foods contain phosphorus, mainly in the form of phosphates and phosphate esters 3). However, phosphorus in seeds and unleavened breads is in the form of phytic acid, the storage form of phosphorus 4). Because human intestines lack the phytase enzyme, much phosphorus in this form is unavailable for absorption 5). Phosphorus undergoes passive absorption in the small intestine, although some is absorbed by active transport 6).

Phosphorus and calcium are interrelated because hormones, such as vitamin D and parathyroid hormone (PTH), regulate the metabolism of both minerals. In addition, phosphorus and calcium make up hydroxyapatite, the main structural component in bones and tooth enamel 7). The combination of high phosphorus intakes with low calcium intakes increases serum PTH levels, but evidence is mixed on whether the increased hormone levels decrease bone mineral density 8).

The kidneys, bones, and intestines regulate phosphorus homeostasis, which requires maintenance of urinary losses at equivalent levels to net phosphorus absorption and ensuring that equal amounts of phosphorus are deposited and resorbed from bone 9). Several hormones, including estrogen and adrenaline, also affect phosphorus homeostasis. When kidney function declines, as in chronic kidney failure, the body cannot excrete phosphate efficiently, and serum levels rise 10).

Although phosphorus status is not typically assessed, phosphate can be measured in both serum and plasma 11). In adults, normal phosphate concentration in serum or plasma is 2.5 to 4.5 mg/dL (0.81 to 1.45 mmol/L) 12). Hypophosphatemia is defined as serum phosphate concentrations lower than the low end of the normal range, whereas a concentration higher than the high end of the range indicates hyperphosphatemia. However, plasma and serum phosphate levels do not necessarily reflect whole-body phosphorus content 13).

Phosphorus recommended intakes

Intake recommendations for phosphorus and other nutrients are provided in the Dietary Reference Intakes (DRIs) developed by the Food and Nutrition Board at the National Academies of Sciences, Engineering, and Medicine 14). Dietary Reference Intake is the general term for a set of reference values used for planning and assessing nutrient intakes of healthy people. These values, which vary by age and sex, include:

  • Recommended Dietary Allowance (RDA): Average daily level of intake sufficient to meet the nutrient requirements of nearly all (97%–98%) healthy individuals; often used to plan nutritionally adequate diets for individuals.
  • Adequate Intake (AI): Intake at this level is assumed to ensure nutritional adequacy; established when evidence is insufficient to develop an RDA.
    Estimated Average Requirement (EAR): Average daily level of intake estimated to meet the requirements of 50% of healthy individuals; usually used to assess the nutrient intakes of groups of people and to plan nutritionally adequate diets for them; can also be used to assess the nutrient intakes of individuals.
  • Tolerable Upper Intake Level (UL): Maximum daily intake unlikely to cause adverse health effects.

Table 1 lists the current Recommended Dietary Allowances (RDAs) for phosphorus 15). For infants from birth to 12 months, the Food and Nutrition Board established an Adequate Intake (AI) for phosphorus that is equivalent to the mean intake of phosphorus in healthy, breastfed infants.

Table 1: Recommended Dietary Allowances (RDAs) for Phosphorus

AgeMaleFemalePregnancyLactation
Birth to 6 months*100 mg100 mg
7–12 months*275 mg275 mg
1–3 years460 mg460 mg
4–8 years500 mg500 mg
9–13 years1,250 mg1,250 mg
14–18 years1,250 mg1,250 mg1,250 mg1,250 mg
19+ years700 mg700 mg700 mg700 mg

Footnote: *Adequate Intake (AI)

[Source 16) ]

Sources of phosphorus

Food

Many different types of foods contain phosphorus, including dairy products, meats and poultry, fish, eggs, nuts, legumes, vegetables, and grains 17). In the United States, dairy products contribute about 20% of total phosphorus intakes, and bakery products (e.g., breads, tortillas, and sweet bakery products) contribute 10% 18). Vegetables and chicken contribute 5% each. The absorption rate for the phosphorus naturally contained in food is 40%–70%; phosphorus from animal sources has a higher absorption rate than that from plants 19). Calcium from foods and supplements can bind to some of the phosphorus in foods and prevent its absorption 20). According to one analysis, a very high calcium intake of 2,500 mg/day binds 0.61–1.05 g phosphorus 21). In infants, phosphorus bioavailability ranges from 85%–90% for human milk to approximately 59% for soy-based formulas 22).

Phosphate additives (e.g., phosphoric acid, sodium phosphate, and sodium polyphosphate) are present in many foods, especially processed food products. These additives are used for such purposes as preserving moisture or color and enhancing and stabilizing frozen foods 23). Foods containing these additives have an average of 67 mg more phosphorus per serving than similar foods not containing the additives, and these additives contribute to overall phosphorus intakes in the United States 24).

Phosphate additives are estimated to contribute 300 to 1,000 mg to total daily phosphorus intakes 25), or about 10%–50% of phosphorus intakes in Western countries 26). The use of phosphate additives is rising, as are the amounts of these additives in foods 27). The absorption rate for the phosphorus in phosphate additives is approximately 70% 28).

Several food sources of phosphorus are listed in Table 2.

Table 2: Selected Food Sources of Phosphorus

FoodMilligrams
(mg) per
serving
Percent
DV*
Yogurt, plain, low fat, 6-ounce container24525
Milk, 2% milkfat, 1 cup22623
Salmon, Atlantic, farmed, cooked, 3 ounces21421
Scallops, breaded and fried, 3 ounces20120
Cheese, mozzarella, part skim, 1.5 ounces19720
Chicken, breast meat, roasted, 3 ounces18218
Lentils, boiled, ½ cup17818
Beef patty, ground, 90% lean meat, broiled, 3 ounces17217
Cashew nuts, dry roasted, 1 ounce13914
Potatoes, Russet, flesh and skin, baked, 1 medium12312
Kidney beans, canned, ½ cup11512
Rice, brown, long-grain, cooked, ½ cup10210
Peas, green, boiled, ½ cup949
Oatmeal, cooked with water, ½ cup909
Egg, hard boiled, 1 large869
Tortillas, corn, 1 medium828
Bread, whole wheat, 1 slice606
Sesame seeds, 1 tablespoon576
Bread, pita, whole wheat, 4-inch pita505
Asparagus, boiled, ½ cup495
Tomatoes, ripe, chopped, ½ cup222
Apple, 1 medium202
Cauliflower, boiled, 1” pieces, ½ cup202
Beverages, carbonated, cola, 1 cup182
Clementine, 1 medium162
Tea, green, brewed, 1 cup00

Footnotes: The U.S. Food and Drug Administration (FDA) developed Daily Values (DVs) to help consumers compare the nutrient contents of products within the context of a total diet. The DV for phosphorus used for the values in Table 2 is 1,000 mg for adults and children age 4 years and older 29). This value, however, is changing to 1,250 mg as the updated Nutrition and Supplement Facts labels are implemented. The updated labels must appear on food products and dietary supplements beginning in January 2020, but they can be used now 30). Foods providing 20% or more of the Daily Value (DV) are considered to be high sources of a nutrient, but foods providing lower percentages of the DV also contribute to a healthful diet.

The U.S. Department of Agriculture’s FoodData Central website [29] lists the nutrient content, including that of phosphorus, in many foods.

Abbreviations: *DV = Daily Value.

[Source 31) ]

Phosphorus dietary supplements

Phosphorus is available in dietary supplements containing only phosphorus, supplements containing phosphorus in combination with other ingredients, and a few multivitamin/multimineral products 32). Phosphorus in supplements is usually in the form of phosphate salts (e.g., dipotassium phosphate or disodium phosphate) or phospholipids (e.g., phosphatidylcholine or phosphatidylserine). Products typically provide 10% or less of the DV for phosphorus, but a small proportion deliver more than 100% 33).

The bioavailability of phosphate salts is approximately 70% 34). The bioavailability of other forms of phosphorus in supplements has not been determined in humans.

What is potassium phosphate used for?

Potassium phosphate (and sodium phosphate) is used to increase phosphorus in your body. Potassium phosphate is used for people who are not getting enough phosphorus from their diet or who need increased amounts.

Phosphorus deficiency

Phosphorus deficiency (hypophosphatemia) is rare in the United States and is almost never the result of low dietary intakes 35). The effects of hypophosphatemia can include anorexia, anemia, proximal muscle weakness, skeletal effects (bone pain, rickets, and osteomalacia), increased infection risk, paresthesias, ataxia, and confusion 36). In most cases, hypophosphatemia is caused by medical conditions, such as hyperparathyroidism, kidney tubule defects, and diabetic ketoacidosis 37).

Groups at risk of phosphorus inadequacy

The following groups are most likely to have inadequate phosphorus status.

Preterm newborns

Phosphorus deficiency in preterm infants is one of the main causes, along with calcium deficiency, of osteopenia of prematurity (impaired bone mineralization) 38). Because two-thirds of fetal bone mineral content is acquired during the third trimester of pregnancy, preterm infants are born with low stores of calcium and phosphorus in their bones 39). The benefits of providing extra phosphorus and calcium for bone health in preterm babies is not clear. However, milk fortified with higher amounts of these minerals and other nutritional components is typically recommended to support overall growth and development 40).

People with genetic phosphate regulation disorders

Rare genetic disorders of phosphorus metabolism include X-linked hypophosphatemic rickets 41). In addition to rickets, patients with this disease develop osteomalacia, pseudofractures (formation of new bone and thickened connective tissue over injured bone), enthesopathy (mineralization of ligaments and tendons), and dental damage. Other rare genetic disorders of phosphorus regulation associated with rickets include autosomal-dominant and autosomal-recessive hypophosphatemic rickets and hereditary hypophosphatemic rickets with hypercalciuria 42). Treatment typically consists of vitamin D and phosphorus supplementation from diagnosis until growth is complete 43).

Patients with severe malnutrition

People with severe protein or calorie malnutrition can develop refeeding syndrome, also known as refeeding hypophosphatemia, within 2 to 5 days of starting enteral or parenteral nutrition because of the shift in metabolism from a catabolic to an anabolic state 44). Causes of malnutrition that can lead to refeeding syndrome include chronic diseases (e.g., cancer, chronic obstructive pulmonary disease, or cirrhosis), very low birthweight, cachexia, low body weight, anorexia nervosa, excessive alcohol intake, and chewing or swallowing problems. The effects of refeeding syndrome can include impaired neuromuscular function, hypoventilation, respiratory failure, impaired blood clotting, confusion, coma, cardiac arrest, congestive heart failure, and death 45). Prophylactic administration of phosphorus and thiamin in patients at risk of refeeding syndrome can prevent this condition 46).

Potassium phosphate special precautions

Before taking potassium phosphate

You should not use potassium phosphate if you have:

  • high levels of potassium in your blood (hyperkalemia);
  • low levels of calcium in your blood (hypocalcemia); or
  • high levels of phosphorus in your blood (hyperphosphatemia).

To make sure potassium phosphate is safe for you, tell your doctor if you have:

  • heart disease;
  • kidney disease; or
  • Addison’s disease (an adrenal gland disorder).

It is not known whether potassium phosphate will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

It is not known whether potassium phosphate passes into breast milk or if it could harm a nursing baby. Tell your doctor if you are breast-feeding a baby.

Potassium phosphate and sodium phosphate should not be given to a child younger than 4 years old without a doctor’s advice. Potassium phosphate injection contains aluminum which can cause harm especially to premature babies. Talk to your doctor if you have concerns about this.

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For potassium phosphate, the following should be considered:

Your doctor will check your progress closely while you are receiving potassium phosphate. This will allow your doctor to see if the medicine is working properly and to decide if you should continue to receive it. Blood tests may be needed to check for unwanted effects.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

Allergies

Tell your doctor if you have ever had any unusual or allergic reaction to potassium phosphate or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Pediatric

No information is available on the relationship of age to the effects of potassium phosphate injection in the pediatric population. Safety and efficacy have not been established.

Geriatric

No information is available on the relationship of age to the effects of potassium phosphate in geriatric patients.

Pregnancy

Pregnancy Category C: Animal studies have shown an adverse effect and there are no adequate studies in pregnant women OR no animal studies have been conducted and there are no adequate studies in pregnant women.

Breastfeeding

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Potassium phosphate drug interactions

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are receiving potassium phosphate, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using potassium phosphate with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Erdafitinib

Other interactions

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Other medical problems

The presence of other medical problems may affect the use of potassium phosphate. Make sure you tell your doctor if you have any other medical problems, especially:

  • Adrenal problems, severe or
  • Heart disease or
  • Heart rhythm problems or
  • Kidney disease, severe—Use with caution. May make these conditions worse.
  • Hyperkalemia (high blood potassium) or
  • Hyperphosphatemia (high blood phosphorus) or
  • Hypocalcemia (low calcium in the blood)—Should not be used in patients with these conditions.
  • Kidney disease—Use with caution. The effect may be increased because of slower removal of the medicine from the body.

Potassium phosphate dosing

A nurse or other trained health professional will give you potassium phosphate injection in a hospital. Potassium phosphate injection is given through a needle placed in a vein.

Adult dose for hypophosphatemia

Hypophosphatemia: Dose and rate of administration are dependent on individual patient needs

  • Total parenteral nutrition: 12 to 15 millimolar phosphorous is recommended for each 500 mL 50% dextrose injection
  • Keep in mind the amount of potassium being infused; monitor serum potassium and/or electrocardiographic changes as needed

Comments:

Must be diluted before administration.

Pediatric dose for hypophosphatemia

Hypophosphatemia: Dose and rate of administration are dependent on individual patient needs

  • Infants receiving total parenteral nutrition: 1.5 to 2 millimolar phosphorous/kg/day
  • Keep in mind the amount of potassium being infused; monitor serum potassium and/or electrocardiographic changes as needed

Comments:

Must be diluted before administration.

Renal dose adjustments

Use with caution in severe renal failure.

Potassium retention may occur in patients with diminished renal function.

Dialysis

Data not available

Liver dose adjustments

Data not available

What happens if I miss a dose?

Use the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not use extra medicine to make up the missed dose.

Potassium phosphate side effects

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor or nurse immediately if any of the following side effects occur:

Incidence not known

  • burning, crawling, itching, numbness, prickling, “pins and needles”, or tingling feelings
  • chest pain or discomfort
  • confusion
  • dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
  • fast, slow, or irregular heartbeat
  • muscle cramps in the hands, arms, feet, legs, or face
  • no muscle tone or movement
  • numbness and tingling around the mouth, fingertips, or feet
  • pounding or rapid pulse
  • shortness of breath
  • unusual tiredness or weakness
  • weakness and heaviness of the legs

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects.

References   [ + ]