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  • CLASSES

    Acidifying Agents
    Bowel Prep Combinations
    Enemas for Constipation
    Osmotically-Acting Laxatives

    BOXED WARNING

    Colitis, GI obstruction, hypovolemia, nephrotoxicity, renal disease, renal failure, renal impairment

    Sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous oral formulations are contraindicated in patients with biopsy proven acute renal failure, including acute phosphate nephropathy. The administration of sodium phosphate salt products prior to colonoscopy for colon cleansing has resulted in several reported cases of nephrotoxicity, including acute renal failure, including acute phosphate nephropathy. Specifically, the FDA has received multiple reports of acute kidney impairment associated with the use of oral sodium phosphate salt products. As a result, product labeling for prescription oral sodium phosphate salt products are required to include a boxed warning addressing the increased risk of acute phosphate nephropathy. Factors that may increase the risk of developing acute phosphate nephropathy include advanced age, hypovolemia, increased bowel transit time (such as bowel obstruction), active colitis, and/or baseline renal disease. Sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous should be used with caution, if at all, in patients with renal disease, including patients with renal impairment (CrCl less than 30 mL/minute). Fatalities due to significant fluid shifts, severe electrolyte abnormalities, and arrhythmias have occurred in patients with renal impairment. In addition, patients concomitantly using medicines that affect renal perfusion or function may also be at an increased risk of developing renal complications. In patients with a history of renal impairment or in patients using medicines that alter renal perfusion or renal function, the clinician should consider performing baseline and post-colonoscopy laboratory tests (serum phosphate, calcium, potassium, sodium, creatinine, and BUN). To minimize the risk of acute renal failure, patients receiving oral sodium phosphate salts should be advised to adequately hydrate before, during, and after the use of sodium phosphate salts; parenteral hydration with hospitalization may be necessary for frail patients who are unable to consume the appropriate amounts of fluids at home. Lastly, these products should be used in a manner that is consistent with package labeling. The concomitant use of other laxatives containing sodium phosphate should be avoided. Intravenous sodium phosphate should also be used with caution in patients with severe renal impairment or renal failure due to the risk of sodium retention and impaired phosphate excretion.

    DEA CLASS

    OTC, Rx

    DESCRIPTION

    Combination of sodium phosphate salts; rectal, oral, or intravenous dosage forms available
    Used as laxative for the occasional relief of constipation, as a bowel preparation agent to evacuate the bowel prior to colonic radiologic examination or surgery, and for the treatment and prevention of hypophosphatemia
    NEVER exceed the recommended dosing; also, rectal use in pediatric patients less than 2 years of age is not advised unless under close physician monitoring due to potential risks

    COMMON BRAND NAMES

    Fleet, OsmoPrep, Ready To Use Saline

    HOW SUPPLIED

    Fleet/Ready To Use Saline/Sodium Phosphate, Dibasic, Sodium Phosphate, Monobasic Rectal Enema
    OsmoPrep Oral Tab
    Sodium Phosphate, Dibasic, Sodium Phosphate, Monobasic Intravenous Inj Sol

    DOSAGE & INDICATIONS

    For use as a bowel evacuant to clean the colon prior to colonoscopy (bowel preparation).
    Oral dosage (e.g., Osmoprep tablets)
    Adults

    32 tablets (48 grams) PO, along with a total of 2 quarts of clear liquids, taken according to the recommended schedule. During the evening before the colonoscopy, 4 tablets should be taken with 8 ounces of clear liquids every 15 minutes for a total of 20 tablets. On the day of the colonoscopy (starting 3 to 5 hours before the procedure), 4 tablets should be taken with 8 ounces of clear liquids every 15 minutes for a total of 12 tablets. Do not repeat this regimen within 7 days of previous administration. No additional enema or laxative is required and patients should be advised not to use additional agents, particularly those containing sodium phosphate. Each tablet contains approximately 314 mg of sodium.

    Rectal dosage (saline enema)
    Adults

    1 bottle (monobasic sodium phosphate 19 g; dibasic sodium phosphate 7 g [volume dependent on product chosen]) rectally. Taking more than the recommended dose in 24 hours can be harmful; do not exceed recommended dosage. Each dose (monobasic sodium phosphate 19 g; dibasic sodium phosphate 7 g) contains 4,400 mg of sodium.

    Children and Adolescents 12 to 17 years

    1 bottle (monobasic sodium phosphate 19 g; dibasic sodium phosphate 7 g [volume dependent on product chosen]) rectally. Taking more than the recommended dose in 24 hours can be harmful; do not exceed recommended dosage. Each dose (monobasic sodium phosphate 19 g; dibasic sodium phosphate 7 g) contains 4,400 mg of sodium.

    Children 5 to 11 years

    1 bottle (59 mL) of pediatric enema formulation rectally. Taking more than the recommended dose in 24 hours can be harmful; do not exceed recommended dosage. Each 59 mL bottle (pediatric formulation) contains 2,200 mg of sodium.

    Children 2 to 4 years

    1/2 bottle (29.5 mL) of pediatric enema formulation rectally. Remove 30 mL of liquid from the bottle with a measuring spoon. Replace the bottle cap and follow enema administration instructions. Taking more than the recommended dose in 24 hours can be harmful; do not exceed recommended dosage. Each 29.5 mL dose (pediatric formulation) contains 1,100 mg of sodium.

    Infants and Children younger than 2 years

    Do not use. The FDA recommends against use due to the risk of severe dehydration and alterations in serum electrolytes.

    For treatment of constipation.
    Rectal dosage (saline enema)
    Adults

    1 bottle (monobasic sodium phosphate 19 g; dibasic sodium phosphate 7 g [volume dependent on product chosen]) rectally. Taking more than the recommended dose in 24 hours can be harmful; do not exceed recommended dosage. Each dose (monobasic sodium phosphate 19 g; dibasic sodium phosphate 7 g) contains 4,400 mg of sodium.

    Children and Adolescents 12 to 17 years

    1 bottle (monobasic sodium phosphate 19 g; dibasic sodium phosphate 7 g [volume dependent on product chosen]) rectally. Taking more than the recommended dose in 24 hours can be harmful; do not exceed recommended dosage. Each dose (monobasic sodium phosphate 19 g; dibasic sodium phosphate 7 g) contains 4,400 mg of sodium.

    Children 5 to 11 years

    1 bottle (59 mL) of pediatric enema formulation rectally. Taking more than the recommended dose in 24 hours can be harmful; do not exceed recommended dosage. Each 59 mL bottle (pediatric formulation) contains 2,200 mg of sodium.

    Children 2 to 4 years

    1/2 bottle (29.5 mL) of pediatric enema formulation rectally. Remove 30 mL of liquid from the bottle with a measuring spoon. Replace the bottle cap and follow enema administration instructions. Taking more than the recommended dose in 24 hours can be harmful; do not exceed recommended dosage. Each 29.5 mL dose (pediatric formulation) contains 1,100 mg of sodium.

    Infants and Children younger than 2 years

    Do not use. The FDA recommends against use due to the risk of severe dehydration and alterations in serum electrolytes.

    For the treatment of hypophosphatemia.
    NOTE: Serum phosphorus cutoff values represent adult concentrations. Normal serum phosphorus concentrations are higher in children, and thus cutoff values for children will be higher. Hypophosphatemia in children is generally defined as a serum phosphorus concentration less than 4 mg/dL; severe hypophosphatemia is generally defined as serum phosphorus concentrations less than 1 to 1.5 mg/dL. However, there is no consensus definition for degrees of hypophosphatemia in children.
    NOTE: Guidelines generally recommend the use of sodium phosphate for potassium serum concentration more than 4 mg/dL and potassium phosphate for potassium serum concentration less than 4 mg/dL.
    NOTE: Sodium phosphate injection contains 3 mmol of phosphorus per mL equivalent to 4 mEq of sodium per mL; 1 mmol of phosphorus weighs 31 mg.
    For the treatment of mild hypophosphatemia (i.e., phosphorus serum concentration 2 to 2.5 mg/dL).
    Intravenous dosage
    Adults

    0.16 to 0.32 mmol/kg/dose (Usual Max: 50 mmol/dose) IV over 2 to 6 hours.

    Infants†, Children†, and Adolescents†

    Data are very limited in children; doses of 0.08 to 0.16 mmol/kg/dose IV over 6 hours have been recommended. 0.16 to 0.32 mmol/kg/dose IV over 2 to 6 hours based on data in adult patients.

    For the treatment of moderate hypophosphatemia (i.e., phosphorus serum concentration 1 to 2 mg/dL).
    Intravenous dosage
    Adults

    0.32 to 0.64 mmol/kg/dose (Usual Max: 50 mmol/dose) IV over 2 to 6 hours.

    Infants†, Children†, and Adolescents†

    Data are very limited in children; doses of 0.08 to 0.16 mmol/kg/dose IV over 6 hours have been recommended. 0.32 to 0.64 mmol/kg/dose (Usual Adult Max: 50 mmol/dose) IV over 2 to 6 hours based on data in adult patients.

    For the treatment of severe hypophosphatemia (i.e., phosphorus serum concentration less than 1 mg/dL).
    Intravenous dosage
    Adults

    0.64 to 1 mmol/kg/dose (Usual Max: 50 mmol/dose) IV over 2 to 6 hours.

    Infants†, Children†, and Adolescents†

    Data are very limited in children; doses as high as 1 mmol/kg/dose IV over 12 hours have been reported in pediatric patients with DKA and severe hypophosphatemia. 0.64 to 1 mmol/kg/dose (Usual Adult Max: 50 mmol/dose) IV over 2 to 6 hours based on data in adult patients.

    For nutritional supplementation to prevent hypophosphatemia in patients receiving parenteral nutrition (PN).
    NOTE: Supplementation of phosphate in PN may be limited by physical incompatibility, particularly in neonates who have higher calcium and phosphate requirements.
    Intravenous dosage
    Adults

    20 to 40 mmol/day IV is recommended by guidelines. Titrate dose depending on patient's clinical condition and desired serum concentrations.

    Children weighing 50 kg or more† and Adolescents†

    10 to 40 mmol/day IV is recommended by guidelines. Titrate dose depending on patient's clinical condition and desired serum concentrations.

    Infants† and Children weighing less than 50 kg†

    0.5 to 2 mmol/kg/day IV is recommended by guidelines. Titrate dose depending on patient's clinical condition and desired serum concentrations.

    Neonates†

    1 to 2 mmol/kg/day IV is recommended by guidelines. Titrate dose depending on patient's clinical condition and desired serum concentrations.

    MAXIMUM DOSAGE

    Health care providers and patients should be aware of the possible risks associated with exceeding the recommended dose of over-the-counter (OTC) sodium phosphate products used to treat constipation. Cases of severe dehydration and altered serum electrolytes resulting in serious adverse effects on organs, such as the kidneys and heart, and in some cases resulting in death, have been reported.

    Adults

    32 tablets (48 g) PO over 2 days; 1 bottle/24 hours rectal enema. Specific maximum dosage information is not available for IV use; however, single maximum doses of 1 mmol/kg/dose IV (Usual Max: 50 mmol/dose) have been used; individualize dosage based on indication, phosphate serum concentrations, and other clinical parameters.

    Geriatric

    32 tablets (48 g) PO over 2 days; 1 bottle/24 hours rectal enema. Specific maximum dosage information is not available for IV use; however, single maximum doses of 1 mmol/kg/dose IV (Usual Max: 50 mmol/dose) have been used; individualize dosage based on indication, phosphate serum concentrations, and other clinical parameters. 

    Adolescents

    1 bottle/24 hours rectal enema; safety and efficacy have not been established for oral tablets. Specific maximum dosage information is not available for IV use; however, single maximum doses of 1 mmol/kg/dose IV (Usual Adult Max: 50 mmol/dose) have been used; individualize dosage based on indication, phosphate serum concentrations, and other clinical parameters.

    Children

    12 years: 1 bottle/24 hours rectal enema; safety and efficacy have not been established for oral tablets. Specific maximum dosage information is not available for IV use; however, single maximum doses of 1 mmol/kg/dose IV (Usual Adult Max: 50 mmol/dose) have been used; individualize dosage based on indication, phosphate serum concentrations, and other clinical parameters.
    5 to 11 years: 1 bottle/24 hours rectal enema for children; safety and efficacy have not been established for oral tablets. Specific maximum dosage information is not available for IV use; however, single maximum doses of 1 mmol/kg/dose IV (Usual Adult Max: 50 mmol/dose) have been used; individualize dosage based on indication, phosphate serum concentrations, and other clinical parameters.
    2 to 4 years: 1/2 bottle/24 hours rectal enema for children; safety and efficacy have not been established for oral tablets. Specific maximum dosage information is not available for IV use; however, single maximum doses of 1 mmol/kg/dose IV have been used; individualize dosage based on indication, phosphate serum concentrations, and other clinical parameters.
    younger than 2 years: Safety and efficacy have not been established for oral or rectal formulations; FDA recommends against use. Specific maximum dosage information is not available for IV use; however, single maximum doses of 1 mmol/kg/dose IV have been used; individualize dosage based on indication, phosphate serum concentrations, and other clinical parameters. 

    Infants

    Safety and efficacy have not been established for oral or rectal formulations; FDA recommends against use. Specific maximum dosage information is not available for IV use; however, single maximum doses of 1 mmol/kg/dose IV have been used; individualize dosage based on indication, phosphate serum concentrations, and other clinical parameters.

    Neonates

    Safety and efficacy have not been established for oral or rectal formulations; FDA recommends against use. Specific maximum dosage information is not available for IV use; individualize dosage based on indication, phosphate serum concentrations, and other clinical parameters.

    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 for IV sodium phosphate replacement, but dosage adjustments are necessary. In end-stage renal disease (ESRD), phosphorous levels are often elevated, leading to the need for phosphate-binding versus phosphate replacement. Use oral sodium phosphate salts with caution in patients with severe renal impairment (CrCl less than 30 mL/minute). Since the kidneys excrete the ionized, inorganic form of phosphate, patients with renal impairment may have difficulty excreting a large phosphate load.

    ADMINISTRATION

    Oral Administration
    Oral Solid Formulations

    OsmoPrep tablets
    On the day before the colonoscopy, the patient can consume a light breakfast consisting of clear soup and/or plain yogurt (no solid foods) before noon, followed by only clear liquids until after the colonoscopy.
    The evening before the colonoscopy procedure, the patient should take 4 tablets with 8 ounces of clear liquids (no solid food) every 15 minutes for a total of 20 tablets. Examples, of clear liquids are water, flavored water, lemonade (no pulp), ginger ale, or apple juice. Do not drink any liquids colored purple or red or any other foods containing pulp material.
    The day of the colonoscopy procedure, starting 3 to 5 hours before the procedure, patient should take 4 tablets with 8 ounces of clear liquids every 15 minutes for a total of 12 tablets.
    Patients should be adequately hydrated before, during, and after treatment with clear liquids to prevent excessive fluid loss and hypovolemia.
    Do not take other oral medications within 1 hour before or after starting each dose.

    Injectable 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.

    Intravenous Administration

    Dilution
    Sodium phosphate injection MUST be diluted prior to administration.
    Dilute in sufficient volume of a compatible IV infusion solution (i.e., 100 to 250 mL of 5% Dextrose Injection or 0.9% NaCl Injection depending on dose). Concentrations as high as 0.45 mmol/mL have been safely used in adult ICU patients.
     
    Intravenous infusion
    Adults: Infuse over 2 to 6 hours. Usual infusion rates are 7.5 to 15 mmol/hour. Rates as high as 20 mmol/hour have been safely used in adult ICU patients.
    Pediatrics: Data are limited; infusion rates of 6 to 12 hours have been used.
     
    Parenteral Nutrition (PN) Preparation
    Parenteral nutrition admixtures containing calcium phosphate precipitates have resulted in embolic deaths when infused.
    Generally, phosphate should be added first to the PN admixture, and calcium should be added to the end of the compounding sequence to take advantage of the maximum volume of PN formulation.

    Rectal Administration

    Rectal saline enema
    The patient should lay on their left side with top knee bent and arms resting comfortably. Alternatively, the patient may kneel, then lower their head and chest forward until left side of the face is resting on a surface with arms folded comfortably.
    With steady pressure, gently insert the enema tip into the rectum with a slight side-to-side movement, with the tip pointing toward the navel. Rectal insertion may be easier if the patient bears down, as if having a bowel movement. This helps relax the muscles around the anus. Do not force the enema tip into the rectum as this can cause injury.
    Squeeze the bottle until nearly all the liquid is gone. It is not necessary to empty the bottle completely, as it contains more liquid than is needed. Remove the enema tip from the rectum and have the patient maintain the selected position until the urge to evacuate is strong (usually 2 to 5 minutes).

    STORAGE

    Generic:
    - Do not freeze
    - Store at room temperature (between 59 to 86 degrees F)
    Fleet:
    - Store between 15 to 30 degrees C (59 - 86 degrees F)
    OsmoPrep:
    - Discard unused portion. Do not store for later use.
    - Store at 77 degrees F; excursions permitted to 59-86 degrees F
    Ready To Use Saline:
    - Store between 15 to 30 degrees C (59 - 86 degrees F)
    Visicol:
    - Discard unused portion. Do not store for later use.
    - Store at 77 degrees F; excursions permitted to 59-86 degrees F

    CONTRAINDICATIONS / PRECAUTIONS

    General Information

    Sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous products are contraindicated in patients with a known allergy or hypersensitivity to sodium phosphate salts or any of the product ingredients. Serious hypersensitivity reactions including anaphylaxis, angioedema, rash, urticaria, and throat tightness have been reported in patients taking sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous products. Patients should be informed of the signs and symptoms of anaphylaxis and should be instructed to seek immediate medical care should signs and symptoms occur.[32160]

    Colitis, GI obstruction, hypovolemia, nephrotoxicity, renal disease, renal failure, renal impairment

    Sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous oral formulations are contraindicated in patients with biopsy proven acute renal failure, including acute phosphate nephropathy. The administration of sodium phosphate salt products prior to colonoscopy for colon cleansing has resulted in several reported cases of nephrotoxicity, including acute renal failure, including acute phosphate nephropathy. Specifically, the FDA has received multiple reports of acute kidney impairment associated with the use of oral sodium phosphate salt products. As a result, product labeling for prescription oral sodium phosphate salt products are required to include a boxed warning addressing the increased risk of acute phosphate nephropathy. Factors that may increase the risk of developing acute phosphate nephropathy include advanced age, hypovolemia, increased bowel transit time (such as bowel obstruction), active colitis, and/or baseline renal disease. Sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous should be used with caution, if at all, in patients with renal disease, including patients with renal impairment (CrCl less than 30 mL/minute). Fatalities due to significant fluid shifts, severe electrolyte abnormalities, and arrhythmias have occurred in patients with renal impairment. In addition, patients concomitantly using medicines that affect renal perfusion or function may also be at an increased risk of developing renal complications. In patients with a history of renal impairment or in patients using medicines that alter renal perfusion or renal function, the clinician should consider performing baseline and post-colonoscopy laboratory tests (serum phosphate, calcium, potassium, sodium, creatinine, and BUN). To minimize the risk of acute renal failure, patients receiving oral sodium phosphate salts should be advised to adequately hydrate before, during, and after the use of sodium phosphate salts; parenteral hydration with hospitalization may be necessary for frail patients who are unable to consume the appropriate amounts of fluids at home. Lastly, these products should be used in a manner that is consistent with package labeling. The concomitant use of other laxatives containing sodium phosphate should be avoided. Intravenous sodium phosphate should also be used with caution in patients with severe renal impairment or renal failure due to the risk of sodium retention and impaired phosphate excretion.

    Abdominal pain, acute abdomen, appendicitis, esophageal stricture, gastroparesis, GI bleeding, GI perforation, hypothyroidism, ileus, inflammatory bowel disease, scleroderma, surgery, toxic megacolon, ulcerative colitis

    Sodium phosphate salts are contraindicated in patients with congenital or toxic megacolon, toxic colitis, gastric bypass or stapling surgery, GI obstruction, and imperforated anus or GI perforation. Fatalities have occurred in patients with GI perforation receiving sodium phosphate salts prior to colonoscopy for colon cleansing. In addition, considerable caution should be taken before administering any sodium phosphate salt product to patients with any the following illnesses: gastroparesis, ileus, severe chronic constipation, acute colitis, or hypomotility syndrome (associated with scleroderma or inadequately treated hypothyroidism). Patients with symptoms suggestive of bowel obstruction (e.g., acute abdomen) or symptoms of appendicitis such as abdominal pain, nausea, or distension should be evaluated prior to initiating bowel evacuation. Because published data suggest that sodium phosphate salt absorption may be enhanced in patients experiencing an acute exacerbation of chronic inflammatory bowel disease (e.g., ulcerative colitis), sodium phosphate salts should be used with caution in such patients. If failure to produce a bowel movement or rectal GI bleeding occurs after the use of sodium phosphate salt laxatives, discontinue immediately. In addition, advise patients to consult their healthcare professional before starting laxative treatment with sodium phosphate salts if they have experienced a sudden change in bowel habits lasting more than 2 weeks or if they have been using a different laxative for more than a week. Also, patients with a history of swallowing difficulties or anatomic narrowing of the esophagus, such as an esophageal stricture, may have difficulty swallowing sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous tablets.

    Acute myocardial infarction, angina, arrhythmia exacerbation, ascites, cardiac arrhythmias, cardiac disease, cardiomyopathy, coronary artery bypass graft surgery (CABG), edema, heart failure, hypertension, peripheral edema, pulmonary edema, QT prolongation, sodium restriction

    Considerable caution should be observed before administering sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous oral tablets to patients at increased risk for arrhythmias (i.e., QT prolongation, uncontrolled cardiac arrhythmias, heart failure, ascites, cardiomyopathy, acute myocardial infarction, unstable angina, or recent cardiac surgery such as coronary artery bypass graft surgery (CABG)). There have been rare, but serious, reports of QT prolongation and arrhythmia exacerbation associated with the use of sodium phosphate salt products; thus, these products should be used with caution in patients taking other medications known to prolong the QT interval. Consider baseline and post-colonoscopy ECGs and laboratory tests (serum phosphate, calcium, potassium, sodium, creatinine, and BUN) for patients at increased risk for serious cardiac arrhythmias. Additionally, sodium phosphorus salt products each contain varying amounts of sodium; the additional sodium load should be taken into consideration when sodium restriction is required, especially in those patients using sodium phosphate salt products as laxatives for chronic constipation. Intravenous sodium phosphate should also be used with caution in patients with cardiac disease, heart failure, and in other clinical conditions where there exists edema with sodium retention, such as peripheral edema, pulmonary edema, and hypertension.

    Dehydration, electrolyte imbalance, hypernatremia, hyperphosphatemia, hypocalcemia, hypokalemia, hypoparathyroidism, pancreatitis, vomiting

    Sodium phosphate injection is contraindicated in diseases where hyperphosphatemia or hypocalcemia may be present and in patients with hypernatremia. Sodium phosphate should be used cautiously in patients with hypoparathyroidism or acute pancreatitis, since these conditions may be associated with hypocalcemia. Additionally, sodium phosphorus salt products each contain varying amounts of sodium; the additional sodium load should be taken into consideration, especially in those patients using sodium phosphate salt products as laxatives for chronic constipation. In patients receiving sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous tablets, the clinician should consider performing baseline and post-colonoscopy laboratory tests (serum phosphate, calcium, potassium, sodium, creatinine, and BUN) in patients with known or suspected electrolyte imbalance. Patients with electrolyte abnormalities such as hyperphosphatemia, hypocalcemia, hypokalemia, and/or hypernatremia, should have their electrolytes corrected before treatment. Also consider laboratory tests if patients develop vomiting and/or signs of dehydration, even if the patient is otherwise healthy. It is recommended that patients receiving sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous be advised to adequately hydrate before, during, and after the use of sodium phosphate salts; parenteral hydration with hospitalization may be necessary for frail patients who are unable to consume the appropriate amounts of fluids at home. Inadequate fluid intake, as with any effective purgative, may lead to excessive fluid loss and hypovolemia. Hypovolemia may increase the patient's risk of developing acute phosphate nephropathy.

    Alcoholism, hyponatremia, seizure disorder, seizures

    For patients with a known or suspected seizure disorder, the clinician should consider performing baseline and post-colonoscopy laboratory tests (serum phosphate, calcium, potassium, sodium, creatinine, and BUN). There have been rare reports of generalized tonic-clonic seizures and/or loss of consciousness associated with use of sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous tablets in patients with no prior history of seizures. The seizure cases have been associated with electrolyte abnormalities and low serum osmolality. The neurologic abnormalities have been resolved with correction of fluid and electrolyte abnormalities. Sodium phosphate salts should be used with caution in patients with a history of seizures and in patients at a higher risk for seizures such as patients using concomitant medications that lower the seizure threshold, patients with known or suspected hyponatremia, or patients withdrawing from benzodiazepines. Patients with a history of alcoholism, who are withdrawing from alcohol, are also at an increased risk for seizures.

    Geriatric

    Use sodium phosphate salts with caution in geriatric patients. Geriatric patients may be at an increased risk for acute phosphate nephropathy following oral administration of sodium phosphate products for colon cleansing prior to colonoscopy. During clinical evaluation, no overall differences in safety or effectiveness have been observed between elderly and younger patients. However, the mean serum phosphate concentrations in geriatric patients are greater compared to those reported for younger patients following administration of sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous tablets. The mean colonoscopy-day serum phosphate concentrations in patients 18 to 64, 65 to 74, and 75 years and older who received 48 grams of sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous tablets have been reported as 7, 7.3, and 8 mg/dL, respectively. In general, dose selection for an elderly 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. Sodium phosphate salts have been known to be substantially excreted by the kidney, and the risk of adverse reactions with sodium phosphate may be greater in patients with impaired renal function. Since elderly patients are more likely to have impaired renal function, consider performing baseline and post-colonoscopy laboratory tests (serum phosphate, calcium, potassium, sodium, creatinine, and BUN) in these patients.

    Children, infants, neonates

    Over-the-counter (OTC) rectal formulations of sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous should not be administered to neonates, infants, or children younger than 2 years of age. Serious adverse effects, associated with exceeding the recommended dose of OTC sodium phosphate products used to treat constipation, have been reported; young children may be at increased risk for experiencing these events. Using more than one dose in a 24-hour period or using higher than recommended single doses can cause severe dehydration and altered serum electrolytes, which can result in serious adverse effects on organs such as the kidneys and heart. In the most serious cases, these effects can be fatal. Safety and efficacy of sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous tablets and injection have not been established in pediatric patients.
     

    Pregnancy

    Animal reproduction studies have not been conducted with sodium phosphate salts. It is unknown if sodium phosphate salts can cause fetal harm when administered during pregnancy or can affect reproduction capacity. Sodium phosphate salts may also exacerbate toxemia of pregnancy (e.g., preeclampsia). Sodium phosphate salts should only be used during pregnancy if clearly needed. Evidence appears to favor PEG-electrolyte solutions as preferred agents over bowel preparations like sodium phosphates (which might have a higher association with fluid and electrolyte abnormalities) when complete bowel evacuation is necessary during pregnancy. Over-the-counter preparations of sodium phosphate salts should not be used in pregnant women without first consulting with a physician. Chronic use of these products may be detrimental, and safer alternatives to treat routine constipation during pregnancy exist. Bone demineralization and bone growth failure have been reported in an exposed infant when a mother had repeatedly used phosphate-based enemas during pregnancy.
     

    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 (i.e., IV sodium phosphate), when required, on the infant during breast-feeding. It is unknown if oral sodium phosphate salts are excreted in human milk. Use sodium phosphate salt tablets for bowel preparation with caution in women who are breast-feeding. Over-the-counter preparations of sodium phosphate salts should not be used in nursing women without first consulting with a physician. For the treatment of routine constipation, other agents (e.g., stool softeners, occasional use of bisacodyl or PEG 3350 solution), are often preferred first line after fiber and fluid therapy during lactation. Use of sodium phosphate, especially long-term use, has been associated with electrolyte disturbances and dehydration.
     

    Biliary cirrhosis, hepatic disease, hepatitis

    Intravenous sodium phosphate should be used with caution in patients with hepatic disease, such as hepatitis or biliary cirrhosis, where there exists edema with sodium retention.

    Premature neonates

    Injectable sodium phosphate formulations contain aluminum (content varies with formulation). Thus, aluminum may reach toxic concentrations with prolonged administration in patients with renal impairment. Premature neonates are at particular risk for aluminum toxicity because of immature renal function and they require large amounts of calcium and phosphate solutions, which contain aluminum. Research indicates that patients with renal impairment, including neonates, who receive parenteral aluminum at rates greater than 4 to 5 mcg/kg/day may accumulate aluminum at concentrations associated with central nervous system and bone toxicity. Tissue loading may occur at lower administration rates.

    Osteomalacia

    Sodium phosphate 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.

    ADVERSE REACTIONS

    Severe

    muscle paralysis / Delayed / Incidence not known
    arrhythmia exacerbation / Early / Incidence not known
    seizures / Delayed / Incidence not known
    bowel ischemia / Delayed / Incidence not known
    peptic ulcer / Delayed / Incidence not known
    anaphylactoid reactions / Rapid / Incidence not known
    bronchospasm / Rapid / Incidence not known
    angioedema / Rapid / Incidence not known
    renal failure (unspecified) / Delayed / Incidence not known
    aluminum toxicity / Delayed / Incidence not known

    Moderate

    hyperphosphatemia / Delayed / 93.0-96.0
    hypokalemia / Delayed / 18.0-22.0
    oral ulceration / Delayed / 0-3.0
    fecal incontinence / Early / Incidence not known
    dehydration / Delayed / Incidence not known
    hypovolemia / Early / Incidence not known
    hypotension / Rapid / Incidence not known
    edema / Delayed / Incidence not known
    tetany / Early / Incidence not known
    hypernatremia / Delayed / Incidence not known
    metabolic acidosis / Delayed / Incidence not known
    hypocalcemia / Delayed / Incidence not known
    fluid retention / Delayed / Incidence not known
    QT prolongation / Rapid / Incidence not known
    colitis / Delayed / Incidence not known
    dyspnea / Early / Incidence not known
    dysphagia / Delayed / Incidence not known
    acute phosphate nephropathy / Delayed / Incidence not known
    phlebitis / Rapid / Incidence not known

    Mild

    nausea / Early / 26.0-26.0
    abdominal pain / Early / 23.0-23.0
    vomiting / Early / 4.0-4.0
    diarrhea / Early / 10.0
    fecal urgency / Early / 10.0
    dizziness / Early / Incidence not known
    headache / Early / Incidence not known
    paresthesias / Delayed / Incidence not known
    muscle cramps / Delayed / Incidence not known
    weakness / Early / Incidence not known
    rash / Early / Incidence not known
    pruritus / Rapid / Incidence not known
    urticaria / Rapid / 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.
    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.
    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.
    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.
    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.
    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.
    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.
    Amiloride: (Moderate) Concomitant use of medicines with potential to alter renal perfusion or function such as diuretics may increase the risk of acute phosphate nephropathy in patients receiving sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous.
    Amiloride; Hydrochlorothiazide, HCTZ: (Moderate) Concomitant use of medicines with potential to alter renal perfusion or function such as diuretics may increase the risk of acute phosphate nephropathy in patients receiving sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous.
    Angiotensin II receptor antagonists: (Moderate) Concomitant use of medicines with potential to alter renal perfusion or function such as angiotensin II receptor antagonists, may increase the risk of acute phosphate nephropathy in patients taking sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous.
    Angiotensin-converting enzyme inhibitors: (Moderate) Concomitant use of medicines with potential to alter renal perfusion or function such as angiotensin-converting enzyme inhibitors, may increase the risk of acute phosphate nephropathy in patients taking sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous.
    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.
    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.
    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.
    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.
    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.
    Aspirin, ASA; Caffeine; Orphenadrine: (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.
    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.
    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.
    Aspirin, ASA; Citric Acid; Sodium Bicarbonate: (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.
    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.
    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.
    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.
    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.
    Atropine; Difenoxin: (Moderate) Diphenoxylate can decrease GI motility. Drugs used to treat constipation, such as laxatives, would counteract the effect of antidiarrheals. In general, it would be illogical to concurrently administer these drugs at the same time. If an antidiarrheal medication is needed, it would be wise to temporarily discontinue use of agents with laxative effects.
    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.
    Bisacodyl: (Moderate) Sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous should not be combined with additional laxatives or purgatives when being used to evacuate the bowel prior to colonic radiologic examinations or surgery.
    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.
    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.
    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.
    Budesonide; Glycopyrrolate; Formoterol: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Bulk-forming laxative: (Moderate) Sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous should not be combined with additional laxatives or purgatives when being used to evacuate the bowel prior to colonic radiologic examinations or surgery.
    Burosumab: (Contraindicated) Oral phosphates are contraindicated in patients receiving burosumab; discontinue sodium phosphate, disbasic, sodium phosphate, monobasic 1 week prior to initiation of burosumab.
    Caffeine: (Major) Sodium phosphates should be used with caution in patients using concomitant medications that lower the seizure threshold like psychostimulants.
    Calcium Acetate: (Moderate) The concomitant use of oral sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous preparations in conjunction with antacids containing calcium (e.g., calcium carbonate, calcium salts) may bind the phosphate in the stomach and reduce its absorption. If the patient requires multiple mineral supplements or concurrent use of antacids, it is prudent to separate the administration of sodium phosphate salts from calcium containing products by at least one hour.
    Calcium Carbonate: (Moderate) The concomitant use of oral sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous preparations in conjunction with antacids containing calcium (e.g., calcium carbonate, calcium salts) may bind the phosphate in the stomach and reduce its absorption. If the patient requires multiple mineral supplements or concurrent use of antacids, it is prudent to separate the administration of sodium phosphate salts from calcium containing products by at least one hour.
    Calcium Carbonate; Famotidine; Magnesium Hydroxide: (Moderate) The concomitant use of oral sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous preparations in conjunction with antacids containing calcium (e.g., calcium carbonate, calcium salts) may bind the phosphate in the stomach and reduce its absorption. If the patient requires multiple mineral supplements or concurrent use of antacids, it is prudent to separate the administration of sodium phosphate salts from calcium containing products by at least one hour.
    Calcium Carbonate; Magnesium Hydroxide: (Moderate) The concomitant use of oral sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous preparations in conjunction with antacids containing calcium (e.g., calcium carbonate, calcium salts) may bind the phosphate in the stomach and reduce its absorption. If the patient requires multiple mineral supplements or concurrent use of antacids, it is prudent to separate the administration of sodium phosphate salts from calcium containing products by at least one hour.
    Calcium Carbonate; Magnesium Hydroxide; Simethicone: (Moderate) The concomitant use of oral sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous preparations in conjunction with antacids containing calcium (e.g., calcium carbonate, calcium salts) may bind the phosphate in the stomach and reduce its absorption. If the patient requires multiple mineral supplements or concurrent use of antacids, it is prudent to separate the administration of sodium phosphate salts from calcium containing products by at least one hour.
    Calcium Carbonate; Risedronate: (Moderate) The concomitant use of oral sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous preparations in conjunction with antacids containing calcium (e.g., calcium carbonate, calcium salts) may bind the phosphate in the stomach and reduce its absorption. If the patient requires multiple mineral supplements or concurrent use of antacids, it is prudent to separate the administration of sodium phosphate salts from calcium containing products by at least one hour.
    Calcium Carbonate; Simethicone: (Moderate) The concomitant use of oral sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous preparations in conjunction with antacids containing calcium (e.g., calcium carbonate, calcium salts) may bind the phosphate in the stomach and reduce its absorption. If the patient requires multiple mineral supplements or concurrent use of antacids, it is prudent to separate the administration of sodium phosphate salts from calcium containing products by at least one hour.
    Calcium Chloride: (Moderate) The concomitant use of oral sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous preparations in conjunction with antacids containing calcium (e.g., calcium carbonate, calcium salts) may bind the phosphate in the stomach and reduce its absorption. If the patient requires multiple mineral supplements or concurrent use of antacids, it is prudent to separate the administration of sodium phosphate salts from calcium containing products by at least one hour.
    Calcium Gluconate: (Moderate) The concomitant use of oral sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous preparations in conjunction with antacids containing calcium (e.g., calcium carbonate, calcium salts) may bind the phosphate in the stomach and reduce its absorption. If the patient requires multiple mineral supplements or concurrent use of antacids, it is prudent to separate the administration of sodium phosphate salts from calcium containing products by at least one hour.
    Calcium: (Moderate) The concomitant use of oral sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous preparations in conjunction with antacids containing calcium (e.g., calcium carbonate, calcium salts) may bind the phosphate in the stomach and reduce its absorption. If the patient requires multiple mineral supplements or concurrent use of antacids, it is prudent to separate the administration of sodium phosphate salts from calcium containing products by at least one hour.
    Calcium; Vitamin D: (Moderate) The concomitant use of oral sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous preparations in conjunction with antacids containing calcium (e.g., calcium carbonate, calcium salts) may bind the phosphate in the stomach and reduce its absorption. If the patient requires multiple mineral supplements or concurrent use of antacids, it is prudent to separate the administration of sodium phosphate salts from calcium containing products by at least one hour.
    Carbonic anhydrase inhibitors: (Moderate) Concomitant use of medicines with potential to alter renal perfusion or function such as carbonic anhydrase inhibitors may increase the risk of acute phosphate nephropathy in patients receiving sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous.
    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.
    Chromium: (Moderate) The concomitant use of oral sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous preparations in conjunction with antacids containing calcium (e.g., calcium carbonate, calcium salts) may bind the phosphate in the stomach and reduce its absorption. If the patient requires multiple mineral supplements or concurrent use of antacids, it is prudent to separate the administration of sodium phosphate salts from calcium containing products by at least one hour.
    Ciclesonide: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Colchicine: (Moderate) Colchicine is an alkaloid that is inhibited by acidifying agents. The colchicine dose may need adjustment
    Corticosteroids: (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.
    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.
    Diphenoxylate; Atropine: (Moderate) Diphenoxylate can decrease GI motility. Drugs used to treat constipation, such as laxatives, would counteract the effect of antidiarrheals. In general, it would be illogical to concurrently administer these drugs at the same time. If an antidiarrheal medication is needed, it would be wise to temporarily discontinue use of agents with laxative effects.
    Erdafitinib: (Major) Avoid coadministration of sodium phosphates with erdafitinib before the initial dose increase period (days 14 to 21) which is based on serum phosphate levels. Sodium phosphates increase serum phosphate levels. Erdafitinib causes hyperphosphatemia as a consequence of FGFR inhibition. Changes in serum phosphate levels by sodium phosphate may interfere with the determination of this initial dose increase and may cause additive hyperphosphatemia.
    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.
    Formoterol; Mometasone: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Hetastarch; Dextrose; Electrolytes: (Moderate) The concomitant use of oral sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous preparations in conjunction with antacids containing calcium (e.g., calcium carbonate, calcium salts) may bind the phosphate in the stomach and reduce its absorption. If the patient requires multiple mineral supplements or concurrent use of antacids, it is prudent to separate the administration of sodium phosphate salts from calcium containing products by at least one hour.
    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.
    Indapamide: (Moderate) Concomitant use of medicines with potential to alter renal perfusion or function such as indapamide may increase the risk of acute phosphate nephropathy in patients receiving sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous.
    Lactulose: (Major) In general, other laxatives, such as sodium phosphate, dibasic, sodium phosphate, monobasic, should not be used concurrently with lactulose, especially during the initial phase of therapy for portal-systemic encephalopathy, because the loose stools resulting from their use may falsely suggest that adequate lactulose dosage has been achieved.
    Loop diuretics: (Moderate) Concomitant use of medicines with potential to alter renal perfusion or function such as diuretics, may increase the risk of acute phosphate nephropathy in patients receiving sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous. In addition, loop diuretics may increase the risk of hypokalemia especially in patients receiving prolonged therapy with laxatives. Monitor serum potassium levels to determine the need for potassium supplementation and/or alteration in drug therapy.
    Lubiprostone: (Moderate) Sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous should not be combined with additional laxatives or purgatives when being used to evacuate the bowel prior to colonic radiologic examinations or surgery.
    Magnesium Citrate: (Moderate) Sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous should not be combined with additional laxatives or purgatives when being used to evacuate the bowel prior to colonic radiologic examinations or surgery.
    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.
    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.
    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.
    Mineral Oil: (Moderate) Patients should be instructed not to administer additional laxatives or purgative agents during treatment with sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous.
    Mometasone: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Nonsteroidal antiinflammatory drugs: (Moderate) Concomitant use of medicines with potential to alter renal perfusion or function such as nonsteroidal anti-inflammatory drugs (NSAIDs) may increase the risk of acute phosphate nephropathy in patients taking sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous.
    Pimozide: (Moderate) According to the manufacturer of pimozide, the drug should not be coadministered with drugs known to cause electrolyte imbalances, such as sodium phosphate, dibasic, sodium phosphate monobasic when used as an enema or bowel cleanser. Pimozide is associated with a well-established risk of QT prolongation and torsade de pointes (TdP), and electrolyte imbalances (e.g., hypokalemia, hypocalcemia, hypomagnesemia) may increase the risk of life-threatening arrhythmias. Pimozide is contraindicated in patients with known hypokalemia or hypomagnesemia.
    Polyethylene Glycol: (Moderate) Sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous should not be combined with additional laxatives or purgatives when being used to evacuate the bowel prior to colonic radiologic examinations or surgery. Use in patients using small doses of polyethylene glycol 3350 (e.g., Miralax) may be permissable, as long as the patient does not use their chronic laxative therapy on the day of the preparation. Watch for electrolyte and fluid abnormalities in all patients using bowel preparations.
    Polyethylene Glycol; Electrolytes: (Moderate) Sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous should not be combined with additional laxatives or purgatives when being used to evacuate the bowel prior to colonic radiologic examinations or surgery. Use in patients using small doses of polyethylene glycol 3350 (e.g., Miralax) may be permissable, as long as the patient does not use their chronic laxative therapy on the day of the preparation. Watch for electrolyte and fluid abnormalities in all patients using bowel preparations.
    Polyethylene Glycol; Electrolytes; Ascorbic Acid: (Moderate) Sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous should not be combined with additional laxatives or purgatives when being used to evacuate the bowel prior to colonic radiologic examinations or surgery. Use in patients using small doses of polyethylene glycol 3350 (e.g., Miralax) may be permissable, as long as the patient does not use their chronic laxative therapy on the day of the preparation. Watch for electrolyte and fluid abnormalities in all patients using bowel preparations.
    Polyethylene Glycol; Electrolytes; Bisacodyl: (Moderate) Sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous should not be combined with additional laxatives or purgatives when being used to evacuate the bowel prior to colonic radiologic examinations or surgery. (Moderate) Sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous should not be combined with additional laxatives or purgatives when being used to evacuate the bowel prior to colonic radiologic examinations or surgery. Use in patients using small doses of polyethylene glycol 3350 (e.g., Miralax) may be permissable, as long as the patient does not use their chronic laxative therapy on the day of the preparation. Watch for electrolyte and fluid abnormalities in all patients using bowel preparations.
    Potassium-sparing diuretics: (Moderate) Concomitant use of medicines with potential to alter renal perfusion or function such as diuretics may increase the risk of acute phosphate nephropathy in patients receiving sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous.
    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.
    Probenecid; Colchicine: (Moderate) Colchicine is an alkaloid that is inhibited by acidifying agents. The colchicine dose may need adjustment
    Pyridoxine, Vitamin B6: (Moderate) The concomitant use of oral sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous preparations in conjunction with antacids containing calcium (e.g., calcium carbonate, calcium salts) may bind the phosphate in the stomach and reduce its absorption. If the patient requires multiple mineral supplements or concurrent use of antacids, it is prudent to separate the administration of sodium phosphate salts from calcium containing products by at least one hour.
    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.
    Spironolactone: (Moderate) Concomitant use of medicines with potential to alter renal perfusion or function such as diuretics may increase the risk of acute phosphate nephropathy in patients receiving sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous.
    Spironolactone; Hydrochlorothiazide, HCTZ: (Moderate) Concomitant use of medicines with potential to alter renal perfusion or function such as diuretics may increase the risk of acute phosphate nephropathy in patients receiving sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous.
    Stool Softners: (Moderate) Patients should be instructed not to administer additional laxatives or purgative agents during treatment with sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous.
    Thiazide diuretics: (Moderate) Concomitant use of medicines with potential to alter renal perfusion or function such as diuretics, may increase the risk of acute phosphate nephropathy in patients taking sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous.
    Triamcinolone: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Triamterene: (Moderate) Concomitant use of medicines with potential to alter renal perfusion or function such as diuretics may increase the risk of acute phosphate nephropathy in patients receiving sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous.
    Triamterene; Hydrochlorothiazide, HCTZ: (Moderate) Concomitant use of medicines with potential to alter renal perfusion or function such as diuretics may increase the risk of acute phosphate nephropathy in patients receiving sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous.
    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.

    PREGNANCY AND LACTATION

    Pregnancy

    Animal reproduction studies have not been conducted with sodium phosphate salts. It is unknown if sodium phosphate salts can cause fetal harm when administered during pregnancy or can affect reproduction capacity. Sodium phosphate salts may also exacerbate toxemia of pregnancy (e.g., preeclampsia). Sodium phosphate salts should only be used during pregnancy if clearly needed. Evidence appears to favor PEG-electrolyte solutions as preferred agents over bowel preparations like sodium phosphates (which might have a higher association with fluid and electrolyte abnormalities) when complete bowel evacuation is necessary during pregnancy. Over-the-counter preparations of sodium phosphate salts should not be used in pregnant women without first consulting with a physician. Chronic use of these products may be detrimental, and safer alternatives to treat routine constipation during pregnancy exist. Bone demineralization and bone growth failure have been reported in an exposed infant when a mother had repeatedly used phosphate-based enemas during pregnancy.
     

    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 (i.e., IV sodium phosphate), when required, on the infant during breast-feeding. It is unknown if oral sodium phosphate salts are excreted in human milk. Use sodium phosphate salt tablets for bowel preparation with caution in women who are breast-feeding. Over-the-counter preparations of sodium phosphate salts should not be used in nursing women without first consulting with a physician. For the treatment of routine constipation, other agents (e.g., stool softeners, occasional use of bisacodyl or PEG 3350 solution), are often preferred first line after fiber and fluid therapy during lactation. Use of sodium phosphate, especially long-term use, has been associated with electrolyte disturbances and dehydration.
     

    MECHANISM OF ACTION

    Sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous contains the salts of sodium and phosphate and has varying functions.
     
    Phosphorus homeostasis
    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.
     
    Sodium homeostasis
    Sodium is the primary extracellular cation. It comprises more than 90% of extracellular cations at its normal concentration of approximately 142 mEq/L. Sodium functions as the primary osmotic determinant in extracellular fluid regulation and tissue hydration. Additionally, sodium regulates the membrane potential of cells and the active transport of molecules across cell membranes. Sodium is a unique electrolyte because, in general, water balance is directly related to its concentration. High sodium concentrations and an increase is plasma osmolality stimulates mechanisms that increase the water content of the body, such as increased thirst and increased antidiuretic hormone (ADH) secretion, which leads to renal conservation of water. During hyponatremia, the decrease in plasma osmolality stops ADH secretion; therefore, renal water excretion leads to an increase in sodium concentration.
     
    Laxative and bowel evacuation effects
    After oral or rectal administration, sodium phosphate salts increase the amount of water present in the bowel due to the hyperosmotic effect of sodium within the small and large intestines. Excess water in the bowel stimulates bowel stretch receptors and stimulates the release of cholecystokinin. As a result of distention, peristalsis increases and stimulates a purgative effect inducing a diarrhea that rapidly and effectively cleanses the entire colon. The purgative effect lasts for approximately 1 to 3 hours following oral administration. Sodium phosphate salts can also alter electrolyte balance.

    PHARMACOKINETICS

    Sodium phosphate salts are administered orally as tablets, rectally as an enema, and intravenously. When used as a laxative or bowel evacuant, sodium phosphate salts are used for their local action in the intestine and colon; no significant systemic distribution or metabolism is expected in otherwise healthy individuals. Phosphate that is absorbed systemically is excreted almost exclusively by the kidneys.

    Oral Route

    Pharmacokinetic studies have only been conducted with higher dose sodium phosphate salt tablets (specifically, the Visicol brand), and only in regard to the effects on gastrointestinal absorption and the resulting serum phosphorus concentrations. In regard to gastrointestinal absorption and effects on serum phosphorus, a two part 60 g test dose has been used to determine concentration-time profiles of serum inorganic phosphorous concentrations. At a median of 3 hours following an initial 30 g oral dose of sodium phosphate salt tablets, serum phosphorus concentrations rise from a mean (+/- standard deviation) baseline of 4 (+/-0.7) mg/dL to 7.7 (+/-1.6) mg/dL. At a median of 4 hours following a second 30 g oral dose, serum phosphorus concentrations rise to a mean of 8.4 (+/-1.9) mg/dL. Serum phosphorus concentrations remain above baseline for a median of 24 hours after administration of the initial dose of sodium phosphate salt tablets (range: 16 to 48 hours). No pharmacokinetic studies have been conducted with OsmoPrep tablets.

    Intravenous Route

    The primary route of phosphate excretion is renal. More than 80% of an administered intravenous sodium phosphate dose is excreted by the kidneys. Fecal excretion accounts for the remainder. The absorption of phosphate is most favorable when phosphate and calcium are administered in equal amounts. Phosphate absorption is also stimulated by vitamin D. Normal plasma concentrations of phosphorus are between 2.5 and 4.5 mg/dL in adults. In pediatric patients, normal plasma concentrations of phosphorus are higher than adults due to the demands of physical growth and vary by age.
    Neonates: 4.8 to 8.2 mg/dL
    Children 1 to 3 years: 3.8 to 6.5 mg/dL
    Children 4 to 11 years: 3.7 to 5.6 mg/dL
    Children and Adolescents 12 to 15 years: 2.9 to 5.4 mg/dL
    Adolescents 16 years and older: 2.7 to 4.7 mg/dL