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  • CLASSES

    Acidifying Agents

    DEA CLASS

    Rx

    DESCRIPTION

    Principal ion in the bone and cartilage; has many functions in the body including carbohydrate metabolism, energy transfer, and muscle contraction; Foods with high amounts include cereal grains, milk, meat, poultry, fish, nuts, seeds, and eggs.

    COMMON BRAND NAMES

    K-Phos

    HOW SUPPLIED

    K-Phos Oral Tab: 500mg
    Potassium Phosphate, Dibasic, Potassium Phosphate, Monobasic Intravenous Sol
    Potassium Phosphate, Dibasic, Potassium Phosphate, Monobasic/Sodium Phosphate, Dibasic, Sodium Phosphate, Monobasic Intravenous Inj Sol

    DOSAGE & INDICATIONS

    For the treatment of hypophosphatemia.
    For phosphate serum concentration below 0.5 mg/dL.
    Intravenous dosage
    Adults, Adolescents, and Children

    0.5 mmol/kg IV over 4 to 6 hours.

    For phosphate serum concentration between 0.5—1 mg/dL.
    Intravenous dosage
    Adults, Adolescents, and Children

    0.25 mmol/kg IV over 4 to 6 hours.

    For nutritional supplementation.
    Recommended dietary allowance (RDA) for phosphorus during nutritional supplementation in healthy individuals.
    Oral dosage
    Adults

    700 mg PO per day. NOTE: Use dose based on age for pregnant and lactating females.

    Adolescents and Children >= 9 years of age

    1,250 mg PO per day. NOTE: Use dose based on age for pregnant and lactating females.

    Children 4—8 years of age

    500 mg PO per day.

    Children 1—3 years of age

    460 mg PO per day.

    Infants 6—12 months of age

    275 mg PO per day based on adequate intake (AI). RDA has not been established.

    Infants < 6 months of age

    100 mg PO per day based on adequate intake (AI). RDA has not been established.

    For prevention of hypophosphatemia in patients receiving total parenteral nutrition (TPN).
    Intravenous dosage
    Adults

    20 to 40 mMol per day IV admixed with TPN. NOTE: Dose depends upon patient's clinical condition and desired serum levels.

    For urinary acidification and to augment the efficacy of methenamine therapy in treating urinary tract infections.
    Oral dosage
    Adults, Adolescents, and Children > 4 years old

    250 mg (8 mmol) of phosphorus PO 4 times daily, given after meals and at bedtime. NOTE: If the urine is difficult to acidify, 250 mg (8 mmol) of phosphorus PO may be administered every 2 hours not to exceed 2 g of phosphorus in 24 hours.

    Children up to 4 years old

    200 mg (6.4 mmol) of phosphorus PO 4 times daily, given after meals and at bedtime.

    MAXIMUM DOSAGE

    Specific maximum dosage information is not available. Individualize dosage based on indication, phosphate serum concentrations, and other clinical parameters in all patient populations.

    DOSING CONSIDERATIONS

    Hepatic Impairment

    Specific guidelines for dosage adjustments in hepatic impairment are not available; it appears that no dosage adjustments are needed.

    Renal Impairment

    Specific guidelines for dosage adjustments in renal impairment are not available; but dosage adjustment is necessary. In ESRD phosphorous levels are often elevated, leading to the need for phosphate-binding versus phosphate replacement.

    ADMINISTRATION

    Oral Administration
    Oral Liquid Formulations

    Oral tablets for solution: Dissolve tablets in 6—8 ounces of water. Let tablets soak in the water for 2—5 minutes or more, and stir. If any particles remain, they may be crushed and stirred vigorously to aid in dissolution.
    Neutra-Phos or Neutra-Phos-K packets: Add the contents of 1 packet to a sufficient amount of water or juice to make 75 ml (2.5 ounces) of an oral solution. Stir for 2—3 minutes or until the powder is totally dissolved. Do not dilute further.
    Neutra-Phos or Neutra-Phos-K bottles: Add the contents of 1 bottle to a sufficient amount of water to make 1 gallon (3.785 liters) of an oral solution. Shake the container for 2—3 minutes or until the powder is totally dissolved. Do not dilute further.

    Injectable Administration

    Parenteral phosphate injections must be diluted prior to administration.
    Visually inspect parenteral products for particulate matter and discoloration prior to administration whenever solution and container permit.
    Check IV compatibility prior to admixing or infusing with other drugs or solutions; phosphate salts may precipitate when mixed with calcium salts under selected circumstances. Precipitation in the admixture is dependent primarily on the concentration of calcium and phosphate in the solution, the pH and temperature of the solution, however, other factors such as amino acid concentration and the presence of other additives must also be observed (see IV Compatibility reports).

    Intravenous Administration

    Intravenous infusion (potassium phosphate)
    Dilute in sufficient volume of a compatible IV infusion solution to allow administration over 4—12 hours. Potassium concentration should not exceed 40 mEq/L.
    Infuse IV at a rate not to exceed 20 mEq of potassium per hour unless cardiac monitoring is undertaken.
     
    Intravenous infusion (sodium phosphate)
    Dilute in sufficient volume of a compatible IV infusion solution to allow administration over 4—12 hours.
    Infuse IV slowly. Rapid administration may produce phosphate toxicity.

    STORAGE

    Generic:
    - Discard product if it contains particulate matter, is cloudy, or discolored
    - Discard unused portion. Do not store for later use.
    - Store at controlled room temperature (between 68 and 77 degrees F)
    K-Phos:
    - Store at controlled room temperature (between 68 and 77 degrees F)

    CONTRAINDICATIONS / PRECAUTIONS

    Urinary tract infection (UTI)

    Phosphorus salts should not be administered to patients with active urinary tract infection (UTI) caused by urea-splitting organisms due to the possible development of struvite stone formation. Also, use cautiously in patients with infected magnesium ammonium phosphate nephrolithiasis because the condition may be exacerbated.

    Preeclampsia, pregnancy

    Phosphorus salts are classified in FDA pregnancy category C. Animal reproduction studies have not been conducted. According to the manufacturer, it is not known whether phosphorus salts can cause fetal harm when administered to a pregnant woman and should only be given to a pregnant woman if clearly needed. Sodium-containing phosphorus salts may exacerbate toxemia of pregnancy (e.g., preeclampsia).

    Breast-feeding

    Maternal phosphorous intake during lactation appears to have no significant effect on phosphorus concentrations normally found in human milk. There appears to be no apparent ill effect of maternal supplementation, when required, on the infant during breast-feeding.

    Geriatric

    In general, dose selection with IV and PO phosphorous salts for a geriatric patient should be cautious, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy in this population. Both potassium-containing and sodium-containing phosphorous salts are substantially excreted by the kidney, and the risk of adverse reactions with these agents may be greater in patients with impaired renal function.

    Hyperkalemia, hypernatremia, hyperphosphatemia, hypocalcemia, sodium restriction

    The administration of phosphorus salts may exacerbate hyperphosphatemia and hypocalcemia. Potassium-containing phosphorus salts may exacerbate hyperkalemia. Sodium-containing phosphorus salts may exacerbate hypernatremia. Also, patients requiring sodium restriction should not receive sodium-containing phosphorus salts.

    Heart failure, hypertension, peripheral edema, pulmonary edema

    Due to the possibility of developing hyperkalemia and subsequent cardiac arrest, potassium-containing phosphorus salts should be used cautiously in patients with cardiac disease. Use particular caution when if administering to a digitalized patient. Sodium-containing phosphorus salts may exacerbate conditions such as heart failure, peripheral edema, pulmonary edema, and hypertension.

    Muscle cramps, rhabdomyolysis

    Phosphorus salts should be administered cautiously to patients who have conditions which may be associated with hyperphosphatemia, hypocalcemia, and/or hyperkalemia. These conditions include rhabdomyolysis, myotonia congenita, heat cramps (myalgia thermica), or muscle cramps until the cause can be determined. In some cases, heat cramps can be a result of high potassium. Due to the possibility of developing hyperkalemia and subsequent cardiac arrest, potassium-containing phosphorus salts should be used cautiously in patients with rhabdomyolysis and strenuous physical exercise (especially unconditioned persons).

    Adrenal insufficiency, dehydration, hypoparathyroidism, pancreatitis, renal disease, renal failure, renal impairment

    Phosphorus salts should be administered cautiously to patients who have conditions which may be associated with hyperphosphatemia and/or hypocalcemia. These conditions include hypoparathyroidism, chronic renal disease, or acute pancreatitis. Due to the possibility of developing hyperkalemia and subsequent cardiac arrest, potassium-containing phosphorus salts should be used cautiously in patients with severe adrenal insufficiency (Addison's disease), acute dehydration, pancreatitis, renal failure or severe renal impairment (< 30% of normal).

    Osteomalacia

    Phosphorus salts should be administered cautiously to patients who have osteomalacia (rickets), which may be associated with hyperphosphatemia and/or hypocalcemia. While rickets may benefit from some phosphate therapy, high serum phosphate concentrations may increase the incidence of extra-skeletal calcification.

    Burns

    Due to the possibility of developing hyperkalemia and subsequent cardiac arrest, potassium-containing phosphorus salts should be used cautiously in patients with extensive tissue breakdown (i.e., severe burns).

    ADVERSE REACTIONS

    Severe

    seizures / Delayed / Incidence not known
    AV block / Early / Incidence not known
    muscle paralysis / Delayed / Incidence not known
    hyperkalemia / Delayed / Incidence not known
    cardiac arrest / Early / Incidence not known
    renal failure (unspecified) / Delayed / Incidence not known

    Moderate

    hypertension / Early / Incidence not known
    hyperphosphatemia / Delayed / Incidence not known
    tetany / Early / Incidence not known
    confusion / Early / Incidence not known
    dyspnea / Early / Incidence not known
    hypocalcemia / Delayed / Incidence not known
    hypotension / Rapid / Incidence not known
    hypokalemia / Delayed / Incidence not known
    fluid retention / Delayed / Incidence not known
    metabolic acidosis / Delayed / Incidence not known
    peripheral edema / Delayed / Incidence not known
    hypernatremia / Delayed / Incidence not known
    phlebitis / Rapid / Incidence not known

    Mild

    muscle cramps / Delayed / Incidence not known
    tremor / Early / Incidence not known
    paresthesias / Delayed / Incidence not known
    weakness / Early / Incidence not known
    vomiting / Early / Incidence not known
    flatulence / Early / Incidence not known
    nausea / Early / Incidence not known
    abdominal pain / Early / Incidence not known
    diarrhea / Early / Incidence not known
    injection site reaction / Rapid / Incidence not known

    DRUG INTERACTIONS

    Acetaminophen; Aspirin, ASA; Caffeine: (Moderate) Acidification of the urine may increase serum concentrations of salicylates by increasing tubular reabsorption of salicylates, however, this interaction is not likely to be clinically significant since the urine is normally acidic. (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
    Acetaminophen; Caffeine; Magnesium Salicylate; Phenyltoloxamine: (Moderate) Acidification of the urine may increase serum concentrations of salicylates by increasing tubular reabsorption of salicylates, however, this interaction is not likely to be clinically significant since the urine is normally acidic.
    Alendronate; Cholecalciferol: (Major) High intake of phosphates concomitantly with vitamin D or vitamin D analogs may lead to hyperphosphatemia. Dose adjustment of vitamin D or vitamin D analogs may be necessary during coadministration with phosphorus salts. Additionally, serum calcium concentrations should be monitored frequently. Monitor more frequently in patients with a history of hypercalcemia.
    Aluminum Hydroxide: (Major) Aluminum hydroxide and magnesium hydroxide (as well as other antacids, i.e. aluminum hydroxide; magnesium carbonate, aluminum hydroxide; magaldrate; magnesium hydroxide, and aluminum hydroxide; magnesium trisilicate) may interact with urinary acidifiers by alkalinizing the urine. Frequent use of these high dose antacids should be avoided in patients receiving urinary acidifiers. (Moderate) The oral absorption of phosphorus is reduced by ingestion of aluminum-containing antacids (e.g., aluminum hydroxide). If the patient requires treatment with aluminum-containing antacids, it may be wise to separate the administration of phosphorus salts from the antacid. In some instances the administration of an aluminum hydroxide product is used therapeutically (e.g., uremia) to decrease serum phosphorus levels, so the administration of phosphorus supplements would dynamically counteract the intended use of these drugs in these settings, assuming hypophosphatemia is not present.
    Aluminum Hydroxide; Magnesium Carbonate: (Major) Aluminum hydroxide and magnesium hydroxide (as well as other antacids, i.e. aluminum hydroxide; magnesium carbonate, aluminum hydroxide; magaldrate; magnesium hydroxide, and aluminum hydroxide; magnesium trisilicate) may interact with urinary acidifiers by alkalinizing the urine. Frequent use of these high dose antacids should be avoided in patients receiving urinary acidifiers. (Moderate) Phosphate may bind magnesium salts and magnesium-containing antacids (e.g., magnesium carbonate, magnesium hydroxide) may limit phosphorus absorption or phosphorus may limit magnesium absorption. If the patient requires magnesium supplements or a magnesium-containing antacid, it may be wise to separate the administration of phosphates from magnesium-containing products. (Moderate) The oral absorption of phosphorus is reduced by ingestion of aluminum-containing antacids (e.g., aluminum hydroxide). If the patient requires treatment with aluminum-containing antacids, it may be wise to separate the administration of phosphorus salts from the antacid. In some instances the administration of an aluminum hydroxide product is used therapeutically (e.g., uremia) to decrease serum phosphorus levels, so the administration of phosphorus supplements would dynamically counteract the intended use of these drugs in these settings, assuming hypophosphatemia is not present.
    Aluminum Hydroxide; Magnesium Hydroxide: (Major) Aluminum hydroxide and magnesium hydroxide (as well as other antacids, i.e. aluminum hydroxide; magnesium carbonate, aluminum hydroxide; magaldrate; magnesium hydroxide, and aluminum hydroxide; magnesium trisilicate) may interact with urinary acidifiers by alkalinizing the urine. Frequent use of these high dose antacids should be avoided in patients receiving urinary acidifiers. (Moderate) Phosphate may bind magnesium salts and magnesium-containing antacids (e.g., magnesium carbonate, magnesium hydroxide) may limit phosphorus absorption or phosphorus may limit magnesium absorption. If the patient requires magnesium supplements or a magnesium-containing antacid, it may be wise to separate the administration of phosphates from magnesium-containing products. (Moderate) The oral absorption of phosphorus is reduced by ingestion of aluminum-containing antacids (e.g., aluminum hydroxide). If the patient requires treatment with aluminum-containing antacids, it may be wise to separate the administration of phosphorus salts from the antacid. In some instances the administration of an aluminum hydroxide product is used therapeutically (e.g., uremia) to decrease serum phosphorus levels, so the administration of phosphorus supplements would dynamically counteract the intended use of these drugs in these settings, assuming hypophosphatemia is not present.
    Aluminum Hydroxide; Magnesium Hydroxide; Simethicone: (Major) Aluminum hydroxide and magnesium hydroxide (as well as other antacids, i.e. aluminum hydroxide; magnesium carbonate, aluminum hydroxide; magaldrate; magnesium hydroxide, and aluminum hydroxide; magnesium trisilicate) may interact with urinary acidifiers by alkalinizing the urine. Frequent use of these high dose antacids should be avoided in patients receiving urinary acidifiers. (Moderate) Phosphate may bind magnesium salts and magnesium-containing antacids (e.g., magnesium carbonate, magnesium hydroxide) may limit phosphorus absorption or phosphorus may limit magnesium absorption. If the patient requires magnesium supplements or a magnesium-containing antacid, it may be wise to separate the administration of phosphates from magnesium-containing products. (Moderate) The oral absorption of phosphorus is reduced by ingestion of aluminum-containing antacids (e.g., aluminum hydroxide). If the patient requires treatment with aluminum-containing antacids, it may be wise to separate the administration of phosphorus salts from the antacid. In some instances the administration of an aluminum hydroxide product is used therapeutically (e.g., uremia) to decrease serum phosphorus levels, so the administration of phosphorus supplements would dynamically counteract the intended use of these drugs in these settings, assuming hypophosphatemia is not present.
    Aluminum Hydroxide; Magnesium Trisilicate: (Major) Aluminum hydroxide and magnesium hydroxide (as well as other antacids, i.e. aluminum hydroxide; magnesium carbonate, aluminum hydroxide; magaldrate; magnesium hydroxide, and aluminum hydroxide; magnesium trisilicate) may interact with urinary acidifiers by alkalinizing the urine. Frequent use of these high dose antacids should be avoided in patients receiving urinary acidifiers. (Moderate) The oral absorption of phosphorus is reduced by ingestion of aluminum-containing antacids (e.g., aluminum hydroxide). If the patient requires treatment with aluminum-containing antacids, it may be wise to separate the administration of phosphorus salts from the antacid. In some instances the administration of an aluminum hydroxide product is used therapeutically (e.g., uremia) to decrease serum phosphorus levels, so the administration of phosphorus supplements would dynamically counteract the intended use of these drugs in these settings, assuming hypophosphatemia is not present.
    Antacids: (Major) Aluminum hydroxide and magnesium hydroxide (as well as other antacids, i.e. aluminum hydroxide; magnesium carbonate, aluminum hydroxide; magaldrate; magnesium hydroxide, and aluminum hydroxide; magnesium trisilicate) may interact with urinary acidifiers by alkalinizing the urine. Frequent use of these high dose antacids should be avoided in patients receiving urinary acidifiers.
    Aspirin, ASA: (Moderate) Acidification of the urine may increase serum concentrations of salicylates by increasing tubular reabsorption of salicylates, however, this interaction is not likely to be clinically significant since the urine is normally acidic. (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
    Aspirin, ASA; Butalbital; Caffeine: (Moderate) Acidification of the urine may increase serum concentrations of salicylates by increasing tubular reabsorption of salicylates, however, this interaction is not likely to be clinically significant since the urine is normally acidic. (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
    Aspirin, ASA; Butalbital; Caffeine; Codeine: (Moderate) Acidification of the urine may increase serum concentrations of salicylates by increasing tubular reabsorption of salicylates, however, this interaction is not likely to be clinically significant since the urine is normally acidic. (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
    Aspirin, ASA; Caffeine; Dihydrocodeine: (Moderate) Acidification of the urine may increase serum concentrations of salicylates by increasing tubular reabsorption of salicylates, however, this interaction is not likely to be clinically significant since the urine is normally acidic. (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
    Aspirin, ASA; Carisoprodol: (Moderate) Acidification of the urine may increase serum concentrations of salicylates by increasing tubular reabsorption of salicylates, however, this interaction is not likely to be clinically significant since the urine is normally acidic. (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
    Aspirin, ASA; Carisoprodol; Codeine: (Moderate) Acidification of the urine may increase serum concentrations of salicylates by increasing tubular reabsorption of salicylates, however, this interaction is not likely to be clinically significant since the urine is normally acidic. (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
    Aspirin, ASA; Dipyridamole: (Moderate) Acidification of the urine may increase serum concentrations of salicylates by increasing tubular reabsorption of salicylates, however, this interaction is not likely to be clinically significant since the urine is normally acidic. (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
    Aspirin, ASA; Omeprazole: (Moderate) Acidification of the urine may increase serum concentrations of salicylates by increasing tubular reabsorption of salicylates, however, this interaction is not likely to be clinically significant since the urine is normally acidic. (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
    Aspirin, ASA; Oxycodone: (Moderate) Acidification of the urine may increase serum concentrations of salicylates by increasing tubular reabsorption of salicylates, however, this interaction is not likely to be clinically significant since the urine is normally acidic. (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
    Aspirin, ASA; Pravastatin: (Moderate) Acidification of the urine may increase serum concentrations of salicylates by increasing tubular reabsorption of salicylates, however, this interaction is not likely to be clinically significant since the urine is normally acidic. (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
    Azelaic Acid; Copper; Folic Acid; Nicotinamide; Pyridoxine; Zinc: (Moderate) It has been reported that high intakes of phosphates, such as are found in dietary supplements or food additives, can interfere with absorption of trace nutrients such as iron, copper, and zinc. The magnitude of the effect may be small, and the interactions require further study to judge clinical significance. The theorized mechanism is the formation of insoluble complexes within the gut. Until more data are available, it may be helpful to separate administration times of phosphorus salts by as much as possible from the oral administration of iron (e.g., iron salts or polysaccharide-iron complex), copper salts, or zinc salts to limit any potential interactions. (Minor) It has been reported that high intakes of phosphates, such as are found in dietary supplements or food additives, can interfere with absorption of trace nutrients such as iron, copper, and zinc. The magnitude of the effect may be small, and the interactions require further study to judge clinical significance. The theorized mechanism is the formation of insoluble complexes within the gut. Until more data are available, it may be helpful to separate administration times of potassium phosphate; sodium phosphateby as much as possible from the oral administration of iron (e.g., iron salts or polysaccharide-iron complex), copper salts, or zinc salts to limit any potential interactions.
    Azelastine; Fluticasone: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Beclomethasone: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Betamethasone: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Bismuth Subsalicylate: (Moderate) Acidification of the urine may increase serum concentrations of salicylates by increasing tubular reabsorption of salicylates, however, this interaction is not likely to be clinically significant since the urine is normally acidic. (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
    Bismuth Subsalicylate; Metronidazole; Tetracycline: (Moderate) Acidification of the urine may increase serum concentrations of salicylates by increasing tubular reabsorption of salicylates, however, this interaction is not likely to be clinically significant since the urine is normally acidic. (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
    Budesonide: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Budesonide; Formoterol: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Caffeine: (Major) Sodium phosphates should be used with caution in patients using concomitant medications that lower the seizure threshold like psychostimulants.
    Calcium Carbonate; Magnesium Hydroxide: (Major) Aluminum hydroxide and magnesium hydroxide (as well as other antacids, i.e. aluminum hydroxide; magnesium carbonate, aluminum hydroxide; magaldrate; magnesium hydroxide, and aluminum hydroxide; magnesium trisilicate) may interact with urinary acidifiers by alkalinizing the urine. Frequent use of these high dose antacids should be avoided in patients receiving urinary acidifiers. (Moderate) Phosphate may bind magnesium salts and magnesium-containing antacids (e.g., magnesium carbonate, magnesium hydroxide) may limit phosphorus absorption or phosphorus may limit magnesium absorption. If the patient requires magnesium supplements or a magnesium-containing antacid, it may be wise to separate the administration of phosphates from magnesium-containing products.
    Calcium: (Moderate) The oral absorption of phosphorus is reduced by ingestion of pharmacologic doses of calcium carbonate or other phosphate-lowering calcium salts (e.g., calcium acetate). There is, however, no significant interference with phosphorus absorption by oral dietary calcium at intakes within the typical adult range. If the patient requires multiple calcium supplements or a calcium-containing antacid, it may be wise to separate the administration of phosphorus salts from calcium-containing products. In some instances the administration of calcium salts or calcium carbonate is used therapeutically (e.g., uremia) to decrease serum phosphorus levels, so the administration of phosphorus supplements would dynamically counteract the intended use of calcium in these settings, assuming hypophosphatemia is not present. Appropriate calcium-phosphorus ratios in vivo are important for proper calcium homeostasis in tissues and bone; if the serum ionized calcium concentration is elevated, the concomitant use of calcium salts and phosphorus salts may increase the risk of calcium deposition in soft tissue.
    Calcium; Vitamin D: (Major) High intake of phosphates concomitantly with vitamin D or vitamin D analogs may lead to hyperphosphatemia. Dose adjustment of vitamin D or vitamin D analogs may be necessary during coadministration with phosphorus salts. Additionally, serum calcium concentrations should be monitored frequently. Monitor more frequently in patients with a history of hypercalcemia.
    Carbetapentane; Guaifenesin; Phenylephrine: (Minor) It has been reported that high intakes of phosphates, such as are found in dietary supplements or food additives, can interfere with absorption of trace nutrients such as iron, copper, and zinc. The magnitude of the effect may be small, and the interactions require further study to judge clinical significance. The theorized mechanism is the formation of insoluble complexes within the gut. Until more data are available, it may be helpful to separate administration times of potassium phosphate; sodium phosphateby as much as possible from the oral administration of iron (e.g., iron salts or polysaccharide-iron complex), copper salts, or zinc salts to limit any potential interactions.
    Carbetapentane; Phenylephrine: (Minor) It has been reported that high intakes of phosphates, such as are found in dietary supplements or food additives, can interfere with absorption of trace nutrients such as iron, copper, and zinc. The magnitude of the effect may be small, and the interactions require further study to judge clinical significance. The theorized mechanism is the formation of insoluble complexes within the gut. Until more data are available, it may be helpful to separate administration times of potassium phosphate; sodium phosphateby as much as possible from the oral administration of iron (e.g., iron salts or polysaccharide-iron complex), copper salts, or zinc salts to limit any potential interactions.
    Chlorpheniramine; Pseudoephedrine: (Minor) It has been reported that high intakes of phosphates, such as are found in dietary supplements or food additives, can interfere with absorption of trace nutrients such as iron, copper, and zinc. The magnitude of the effect may be small, and the interactions require further study to judge clinical significance. The theorized mechanism is the formation of insoluble complexes within the gut. Until more data are available, it may be helpful to separate administration times of potassium phosphate; sodium phosphateby as much as possible from the oral administration of iron (e.g., iron salts or polysaccharide-iron complex), copper salts, or zinc salts to limit any potential interactions.
    Cholecalciferol, Vitamin D3: (Major) High intake of phosphates concomitantly with vitamin D or vitamin D analogs may lead to hyperphosphatemia. Dose adjustment of vitamin D or vitamin D analogs may be necessary during coadministration with phosphorus salts. Additionally, serum calcium concentrations should be monitored frequently. Monitor more frequently in patients with a history of hypercalcemia.
    Choline Salicylate; Magnesium Salicylate: (Moderate) Acidification of the urine may increase serum concentrations of salicylates by increasing tubular reabsorption of salicylates, however, this interaction is not likely to be clinically significant since the urine is normally acidic.
    Ciclesonide: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Cod Liver Oil: (Major) Concurrent administration of phosphorus salts and cod liver oil may lead to ergocalciferol-induced increases in serum phosphorus levels. (Major) High intake of phosphates concomitantly with vitamin D or vitamin D analogs may lead to hyperphosphatemia. Dose adjustment of vitamin D or vitamin D analogs may be necessary during coadministration with phosphorus salts. Additionally, serum calcium concentrations should be monitored frequently. Monitor more frequently in patients with a history of hypercalcemia.
    Colchicine: (Moderate) Colchicine is an alkaloid that is inhibited by acidifying agents. The colchicine dose may need adjustment
    Colestipol: (Moderate) Colestipol may interfere with the oral absorption of phosphorus salts. According to the manufacturer, administer other drugs at least 1 hour before or at least 4-6 hours after the administration of colestipol. The manufacturer also recommends that the interval between the administration of colestipol and other drugs should be as long as possible.
    Corticosteroids: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Corticotropin, ACTH: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Cortisone: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Cyclosporine: (Moderate) Use potassium phosphates cautiously with cyclosporine, as both drugs increase serum potassium concentrations. Concurrent use can cause hyperkalemia, especially in elderly patients or patients with impaired renal function. Patients should have serum potassium concentration determinations at periodic intervals.
    Deflazacort: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Dexamethasone: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Diazoxide: (Moderate) Use sodium phosphates cautiously with diazoxide, as concurrent use can cause hypernatremia.
    Dichlorphenamide: (Moderate) Use dichlorphenamide and sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including laxatives. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Diflunisal: (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
    Digoxin: (Minor) Monitor the use of potassium phosphates closely in patients with cardiac arrhythmias (e.g., atrial fibrillation, atrial flutter, digitalis toxicity (except due to documented hypokalemia), and ventricular arrhythmias including ventricular fibrillation and ventricular tachycardia), including patients receiving digoxin or other antiarrhythmic therapy. Both hypokalemia and hyperkalemia increase the risk of digoxin toxicity. Although hyperkalemia can impair AV conduction, potassium-containing phosphorous salts can be coadministered with digoxin because these patients are often receiving potassium-depleting diuretics. Nevertheless, potassium-based phosphorus salts should be used cautiously in patients receiving cardiac glycosides.
    Eplerenone: (Severe) Eplerenone should not be used concomitantly with potassium supplements (including dietary salt substitutes containing potassium) because of the increased risk of developing hyperkalemia. The use of eplerenone in hypertensive patients treated with these medications is contraindicated. When medically necessary to replace losses, use potassium phosphates cautiously with eplerenone, as both drugs increase serum potassium concentrations. Those at risk for hyperkalemia include elderly patients or patients with impaired renal function. Patients at risk for hyperkalemia include elderly patients or patients with impaired renal function. Patients should have serum potassium and other electrolyte concentration determinations at periodic intervals.
    Ergocalciferol, Vitamin D2: (Major) High intake of phosphates concomitantly with vitamin D or vitamin D analogs may lead to hyperphosphatemia. Dose adjustment of vitamin D or vitamin D analogs may be necessary during coadministration with phosphorus salts. Additionally, serum calcium concentrations should be monitored frequently. Monitor more frequently in patients with a history of hypercalcemia.
    Ethanol: (Major) Sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous has been associated with seizure activity in patients with or without a prior history of seizures. Abrupt withdrawal from ethanol may increase the risk of seizures. Close monitoring is advised in patients receiving sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous who are withdrawing from ethanol.
    Fish Oil, Omega-3 Fatty Acids (Dietary Supplements): (Major) High intake of phosphates concomitantly with vitamin D or vitamin D analogs may lead to hyperphosphatemia. Dose adjustment of vitamin D or vitamin D analogs may be necessary during coadministration with phosphorus salts. Additionally, serum calcium concentrations should be monitored frequently. Monitor more frequently in patients with a history of hypercalcemia.
    Fludrocortisone: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Flunisolide: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Fluticasone: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Fluticasone; Salmeterol: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Fluticasone; Umeclidinium; Vilanterol: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Fluticasone; Vilanterol: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Food: (Moderate) Food or medicines containing a high potassium content such as salt substitutes could increase the risk of complications of potassium excess when given with potassium-based phosphorous salts. (Moderate) Foods containing oxalates (found in vegetables like rhubarb, tomatoes, celery, and spinach; as well as berries, beans, nuts and chocolate) or phytates (found in bran and whole-grain cereals) may reduce the absorption of phosphorus by forming complexes with the phosphorus salt.
    Formoterol; Mometasone: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Heparin: (Moderate) Use potassium phosphates cautiously with heparin, as both drugs increase serum potassium concentrations. Concurrent use can cause hyperkalemia, especially in elderly patients or patients with impaired renal function. Patients should have serum potassium concentration determinations at periodic intervals.
    Hetastarch; Dextrose; Electrolytes: (Moderate) Phosphate may bind magnesium salts and magnesium-containing antacids (e.g., magnesium carbonate, magnesium hydroxide) may limit phosphorus absorption or phosphorus may limit magnesium absorption. If the patient requires magnesium supplements or a magnesium-containing antacid, it may be wise to separate the administration of phosphates from magnesium-containing products.
    Hydralazine: (Moderate) Use sodium phosphates cautiously with hydralazine as concurrent use can cause hypernatremia.
    Hydralazine; Hydrochlorothiazide, HCTZ: (Moderate) Use sodium phosphates cautiously with hydralazine as concurrent use can cause hypernatremia.
    Hydralazine; Isosorbide Dinitrate, ISDN: (Moderate) Use sodium phosphates cautiously with hydralazine as concurrent use can cause hypernatremia.
    Hydrochlorothiazide, HCTZ; Methyldopa: (Moderate) Use sodium phosphates cautiously with methyldopa, as concurrent use can cause hypernatremia.
    Hydrocortisone: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Iron: (Moderate) It has been reported that high intakes of phosphates, such as are found in dietary supplements or food additives, can interfere with absorption of trace nutrients such as iron, copper, and zinc. The magnitude of the effect may be small, and the interactions require further study to judge clinical significance. The theorized mechanism is the formation of insoluble complexes within the gut. Until more data are available, it may be helpful to separate administration times of phosphates by as much as possible from the oral administration of iron (e.g., iron salts or polysaccharide-iron complex), copper salts, or zinc salts to limit any potential interactions.
    Magnesium Hydroxide: (Major) Aluminum hydroxide and magnesium hydroxide (as well as other antacids, i.e. aluminum hydroxide; magnesium carbonate, aluminum hydroxide; magaldrate; magnesium hydroxide, and aluminum hydroxide; magnesium trisilicate) may interact with urinary acidifiers by alkalinizing the urine. Frequent use of these high dose antacids should be avoided in patients receiving urinary acidifiers. (Moderate) Phosphate may bind magnesium salts and magnesium-containing antacids (e.g., magnesium carbonate, magnesium hydroxide) may limit phosphorus absorption or phosphorus may limit magnesium absorption. If the patient requires magnesium supplements or a magnesium-containing antacid, it may be wise to separate the administration of phosphates from magnesium-containing products.
    Magnesium Salicylate: (Moderate) Acidification of the urine may increase serum concentrations of salicylates by increasing tubular reabsorption of salicylates, however, this interaction is not likely to be clinically significant since the urine is normally acidic.
    Magnesium Salts: (Moderate) Phosphate may bind magnesium salts and magnesium-containing antacids (e.g., magnesium carbonate, magnesium hydroxide) may limit phosphorus absorption or phosphorus may limit magnesium absorption. If the patient requires magnesium supplements or a magnesium-containing antacid, it may be wise to separate the administration of phosphates from magnesium-containing products.
    Magnesium: (Moderate) Phosphate may bind magnesium salts and magnesium-containing antacids (e.g., magnesium carbonate, magnesium hydroxide) may limit phosphorus absorption or phosphorus may limit magnesium absorption. If the patient requires magnesium supplements or a magnesium-containing antacid, it may be wise to separate the administration of phosphates from magnesium-containing products.
    Methadone: (Minor) As methadone is a weak base, the renal elimination of methadone is increased by urine acidification. Thus acidifying agents may lower the serum methadone concentration. The limited amounts of circulating methadone that undergo glomerular filtration are partially reabsorbed by the kidney tubules, and this reabsorption is pH-dependent. Several studies have demonstrated that methadone is cleared faster from the body with an acidic urinary pH as compared with a more basic pH.
    Methyldopa: (Moderate) Use sodium phosphates cautiously with methyldopa, as concurrent use can cause hypernatremia.
    Methylprednisolone: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Mometasone: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Penicillin G: (Moderate) Use potassium phosphates cautiously with high-doses of IV potassium penicillin G, as both drugs increase serum potassium concentrations. Concurrent use can cause hyperkalemia, especially in elderly patients or patients with impaired renal function. Patients should have serum potassium concentration determinations at periodic intervals.
    Prednisolone: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Prednisone: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Salsalate: (Moderate) Acidification of the urine may increase serum concentrations of salicylates by increasing tubular reabsorption of salicylates, however, this interaction is not likely to be clinically significant since the urine is normally acidic.
    Sevelamer: (Severe) Pharmacologically, sevelamer decreases serum phosphate concentrations. Therefore, phosphate salts would be expected to counteract the pharmacological benefits of sevelamer. It would be illogical to administer phosphate or phosphorus salts to patients who require sevelamer.
    Sucralfate: (Moderate) Serum phosphorus should be checked routinely in patients treated chronically with sucralfate; sucralfate may cause hypophosphatemia and some patients may require phosphorus repletion. This nutrient interaction should be considered in patients receiving phosphates for dietary supplementation. It appears that sucralfate chelates phosphorus in the gut, forming nonabsorbable complexes. Because of sucralfate's therapeutic effect, this interaction may not be prevented by separating times of oral administration.
    Sulfamethoxazole; Trimethoprim, SMX-TMP, Cotrimoxazole: (Moderate) Use potassium phosphate cautiously with trimethoprim (especially high dose), as both drugs increase serum potassium concentrations. Concurrent use can cause hyperkalemia, especially in elderly patients or patients with impaired renal function. Patients should have serum potassium concentration determinations at periodic intervals.
    Triamcinolone: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Trientine: (Major) In general, oral mineral supplements should not be given since they may block the oral absorption of trientine. However, iron deficiency may develop, especially in children and menstruating or pregnant women, or as a result of the low copper diet recommended for Wilson's disease. If necessary, iron may be given in short courses, but since iron and trientine each inhibit oral absorption of the other, 2 hours should elapse between administration of trientine and iron doses.
    Trimethoprim: (Moderate) Use potassium phosphate cautiously with trimethoprim (especially high dose), as both drugs increase serum potassium concentrations. Concurrent use can cause hyperkalemia, especially in elderly patients or patients with impaired renal function. Patients should have serum potassium concentration determinations at periodic intervals.
    Vitamin D analogs: (Major) High intake of phosphates concomitantly with vitamin D analogs may lead to hyperphosphatemia. Dose adjustment of vitamin D analogs may be necessary during coadministration with phosphorus salts. Additionally, serum calcium concentrations should be monitored frequently. Monitor more frequently in patients with a history of hypercalcemia.
    Vitamin D: (Major) High intake of phosphates concomitantly with vitamin D or vitamin D analogs may lead to hyperphosphatemia. Dose adjustment of vitamin D or vitamin D analogs may be necessary during coadministration with phosphorus salts. Additionally, serum calcium concentrations should be monitored frequently. Monitor more frequently in patients with a history of hypercalcemia.
    Zinc Salts: (Minor) It has been reported that high intakes of phosphates, such as are found in dietary supplements or food additives, can interfere with absorption of trace nutrients such as iron, copper, and zinc. The magnitude of the effect may be small, and the interactions require further study to judge clinical significance. The theorized mechanism is the formation of insoluble complexes within the gut. Until more data are available, it may be helpful to separate administration times of potassium phosphate; sodium phosphateby as much as possible from the oral administration of iron (e.g., iron salts or polysaccharide-iron complex), copper salts, or zinc salts to limit any potential interactions.
    Zinc: (Minor) It has been reported that high intakes of phosphates, such as are found in dietary supplements or food additives, can interfere with absorption of trace nutrients such as iron, copper, and zinc. The magnitude of the effect may be small, and the interactions require further study to judge clinical significance. The theorized mechanism is the formation of insoluble complexes within the gut. Until more data are available, it may be helpful to separate administration times of potassium phosphate; sodium phosphateby as much as possible from the oral administration of iron (e.g., iron salts or polysaccharide-iron complex), copper salts, or zinc salts to limit any potential interactions.

    PREGNANCY AND LACTATION

    Pregnancy

    Phosphorus salts are classified in FDA pregnancy category C. Animal reproduction studies have not been conducted. According to the manufacturer, it is not known whether phosphorus salts can cause fetal harm when administered to a pregnant woman and should only be given to a pregnant woman if clearly needed. Sodium-containing phosphorus salts may exacerbate toxemia of pregnancy (e.g., preeclampsia).

    MECHANISM OF ACTION

    Mechanism of Action: Phosphorus has numerous functions in the human body. In addition to its well-known role as a structural component of teeth and bone, phosphorus also serves as a buffer in intracellular and renal tubular fluids, and is an essential element of nucleic acids, phospholipid cell membranes, and phosphoproteins. Phospholipids present in cell membranes serve as regulators of solute transport into and out of cells. Phosphoproteins are required for mitochondrial function. Other functions of phosphorus include regulation of the intermediary metabolism of carbohydrates, fats, and proteins; regulation of enzymatic reactions including glycolysis, ammoniagenesis, 1-hydroxylation of 25-hydroxyvitamin D; and regulation of the oxygen-carrying capacity of hemoglobin.Phosphorus is present in high-energy adenosine triphosphate (ATP) bonds, which fuel a variety of physiological processes, including muscle contractions, neurologic function, and electrolyte transport, as well as other important biochemical reactions. Intracellular inorganic phosphate serves as the phosphorus source from which ATP is resynthesized. The prime determinant of intracellular inorganic phosphate is extracellular inorganic phosphate.The relationship between phosphorus and calcium is a reciprocal one and is regulated partially by parathyroid hormone. Parathyroid hormone decreases the reabsorption of phosphate by the kidney, thereby lowering phosphate levels. The hormone stimulates an increase in calcium levels by increasing bone resorption, gut calcium absorption, and reabsorption of calcium in renal tubules. When serum phosphorus levels are high, serum calcium levels are generally low, and vice versa.

    PHARMACOKINETICS

    Phosphorus salts are administered orally or intravenously. 
     
    The primary route of phosphate excretion is renal. Approximately 90% of an administered dose is excreted by the kidneys. Fecal excretion accounts for the remaining 10%.

    Oral Route

    Following oral administration, phosphate is absorbed via an active, energy-dependent process. Essentially all orally administered phosphate is absorbed. Due to the formation of insoluble complexes, foods or drugs containing large amounts of calcium or aluminum decrease the amount of phosphate absorbed. The absorption of phosphate is most favorable when phosphate and calcium are administered in equal amounts (as in milk). Phosphate absorption is also stimulated by vitamin D. Plasma levels of inorganic phosphate are between 2.5 and 4.4 mg/dl. 

    Intravenous Route

    The absorption of phosphate is most favorable when phosphate and calcium are administered in equal amounts. Phosphate absorption is also stimulated by vitamin D. Plasma levels of inorganic phosphate are between 2.5 and 4.4 mg/dl.