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Sodium Phosphates

Medically reviewed by Drugs.com. Last updated on Jan 6, 2019.

Pronunciation

See also: Amitiza

(SOW dee um FOS fates)

Index Terms

  • Phosphates, Sodium
  • Sod Phos Mono/Sod Phos Dibas

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Injection, solution [concentrate; preservative free]: Phosphorus 3 mmol and sodium 4 mEq per 1 mL (5 mL, 15 mL, 50 mL [DSC]) [equivalent to phosphorus 93 mg and sodium 92 mg per 1 mL; source of electrolytes: monobasic and dibasic sodium phosphate]

Solution, oral: Monobasic sodium phosphate monohydrate 2.4 g and dibasic sodium phosphate heptahydrate 0.9 g per 5 mL (45 mL) [sugar free; contains sodium 556 mg/5 mL, sodium benzoate; ginger-lemon flavor]

Solution, rectal [enema]: Monobasic sodium phosphate monohydrate 19 g and dibasic sodium phosphate heptahydrate 7 g per 118 mL delivered dose (133 mL)

Fleet Enema: Monobasic sodium phosphate monohydrate 19 g and dibasic sodium phosphate heptahydrate 7 g per 118 mL delivered dose (133 mL) [contains sodium 4.4 g/118 mL]

Fleet Enema Extra: Monobasic sodium phosphate monohydrate 19 g and dibasic sodium phosphate heptahydrate 7 g per 197 mL delivered dose (230 mL) [contains sodium 4.4 g/197 mL]

Fleet Pedia-Lax™ Enema: Monobasic sodium phosphate monohydrate 9.5 g and dibasic sodium phosphate heptahydrate 3.5 g per 59 mL delivered dose (66 mL) [contains sodium 2.2 g/59 mL]

LaCrosse Complete: Monobasic sodium phosphate monohydrate 19 g and dibasic sodium phosphate heptahydrate 7 g per 118 mL delivered dose (133 mL) [contains sodium 4.4 g/118 mL]

Tablet, oral [scored]:

OsmoPrep: Monobasic sodium phosphate monohydrate 1.102 g and dibasic sodium phosphate anhydrous 0.398 g [sodium phosphate 1.5 g per tablet; gluten free]

Brand Names: U.S.

  • Fleet Enema Extra [OTC]
  • Fleet Enema [OTC]
  • Fleet Pedia-Lax Enema [OTC]
  • LaCrosse Complete [OTC]
  • OsmoPrep

Pharmacologic Category

  • Cathartic
  • Electrolyte Supplement, Parenteral
  • Laxative, Bowel Evacuant

Pharmacology

As a laxative, exerts osmotic effect in the small intestine by drawing water into the lumen of the gut, producing distention and promoting peristalsis and evacuation of the bowel; phosphorous participates in bone deposition, calcium metabolism, utilization of B complex vitamins, and as a buffer in acid-base equilibrium

Absorption

Oral: ~1% to 20%

Excretion

Oral forms excreted in feces; IV forms are excreted in the urine with over 80% to 90% of dose reabsorbed by the kidney

Onset of Action

Cathartic: 3 to 6 hours; Rectal: 2 to 5 minutes

Special Populations: Renal Function Impairment

Oral: Elimination of the large oral phosphate load may be impaired. Use with caution.

Special Populations: Elderly

Oral: Plasma half-life is 2-fold higher in subjects >70 years of age.

Use: Labeled Indications

Oral solution, rectal: Short-term treatment of constipation

Oral tablets: Bowel cleansing prior to colonoscopy

IV: Source of phosphate in large volume IV fluids and parenteral nutrition; treatment and prevention of hypophosphatemia

Contraindications

Hypersensitivity to sodium phosphate salts or any component of the formulation; additional contraindications vary by product:

Intravenous preparation: Diseases with hyperphosphatemia, hypocalcemia, or hypernatremia

Tablets: Acute phosphate nephropathy, bowel obstruction, bowel perforation, gastric bypass or stapling surgery, toxic colitis, toxic megacolon

OTC labeling (Oral Solution): When used for self-medication: Dehydration, heart failure, renal impairment, electrolyte abnormalities; use for bowel cleansing, use in children <5 years of age

Dosing: Adult

Note: If phosphate repletion is required and a phosphate product is not available at your institution, consider the use of sodium glycerophosphate pentahydrate (Glycophos) as a suitable substitute. Concentration and dosing are different from FDA-approved products; use caution when switching between products. Refer to Sodium Glycerophosphate Pentahydrate monograph.

Caution: With orders for IV phosphate, there is considerable confusion associated with the use of millimoles (mmol) versus milliequivalents (mEq) to express the phosphate requirement. The most reliable method of ordering IV phosphate is by millimoles, then specifying the potassium or sodium salt. Intravenous doses listed as mmol of phosphate.

Acute treatment of hypophosphatemia: IV: It is difficult to provide concrete guidelines for the treatment of severe hypophosphatemia because the extent of total body deficits and response to therapy are difficult to predict. Aggressive doses of phosphate may result in a transient serum elevation followed by redistribution into intracellular compartments or bone tissue. It is recommended that repletion of severe hypophosphatemia be done IV because large doses of oral phosphate may cause diarrhea and intestinal absorption may be unreliable. Intermittent IV infusion should be reserved for severe depletion situations; requires continuous cardiac monitoring. Guidelines differ based on degree of illness, need/use of TPN, and severity of hypophosphatemia. If hypokalemia exists (some clinicians recommend threshold of <4 mmol/L), consider phosphate replacement strategy with potassium (eg, potassium phosphates). Obese patients and/or severe renal impairment were excluded from phosphate supplement trials. Note: 1 mmol phosphate = 31 mg phosphorus; 1 mg phosphorus = 0.032 mmol phosphate.

Critically ill adult patients receiving concurrent enteral/parenteral nutrition (Brown 2006; Clark 1995): Note: Round doses to the nearest 7.5 mmol for ease of preparation. If administering with phosphate-containing parenteral nutrition, do not exceed 15 mmol/L within parenteral nutrition. May use adjusted body weight for patients weighing >130% of ideal body weight (and BMI <40 kg/m2) by using [IBW + 0.25 (ABW-IBW)]:

Low dose, serum phosphorus level 2.3 to 3 mg/dL (0.74 to 0.96 mmol/L): 0.16 to 0.32 mmol/kg over 4 to 6 hours

Intermediate dose, serum phosphorus level 1.6 to 2.2 mg/dL (0.51 to 0.71 mmol/L): 0.32 to 0.64 mmol/kg over 4 to 6 hours

High dose, serum phosphorus <1.5 mg/dL (<0.5 mmol/L): 0.64 to 1 mmol/kg over 8 to 12 hours

Parenteral nutrition: IV: 10 to 15 mmol/1,000 kcal (Hicks 2001) or 20 to 40 mmol/24 hours (Mirtallo 2004 [ASPEN guidelines])

Laxative (Fleet): Rectal: Contents of one 4.5 oz enema as a single dose

Laxative: Oral solution: 15 mL as a single dose; maximum single daily dose: 45 mL

Bowel cleansing prior to colonoscopy: Oral tablets: Note: Do not use additional laxatives, especially other sodium phosphate products. A minimum of 7 days should elapse prior to repeat use.

OsmoPrep: A total of 32 tablets and 2 quarts of clear liquids (8 ounces of clear liquids with each dose) divided as follows:

Evening before colonoscopy: 4 tablets every 15 minutes for 5 doses (total of 20 tablets)

3 to 5 hours prior to colonoscopy: 4 tablets every 15 minutes for 3 doses (total of 12 tablets)

Dosing: Geriatric

Use with caution due to increased risk of renal impairment in the elderly. Refer to adult dosing.

Dosing: Pediatric

Note: If phosphate repletion is required and a phosphate product is not available at your institution, consider the use of sodium glycerophosphate pentahydrate (Glycophos) as a suitable substitute. Concentration and dosing are different from FDA approved products; use caution when switching between products. Refer to sodium glycerophosphate pentahydrate monograph.

Caution: With orders for IV phosphate, there is considerable confusion associated with the use of millimoles (mmol) versus milliequivalents (mEq) to express the phosphate requirement. The most reliable method of ordering IV phosphate is by millimoles, then specifying the potassium or sodium salt. Intravenous doses listed as mmol of phosphate. Note: Consider the contribution of sodium when determining the appropriate phosphate replacement.

Phosphorus − Recommended Daily Allowance (RDA) and Estimated Average Requirement (EAR)

Age

RDA

(mmol/day)

EAR

(mmol/day)

AAdequate intake (AI)

1-6 mo

3.2A

7-12 mo

8.9A

1-3 y

14.8

12.3

4-8 y

16.1

13.1

9-18 y

40.3

34

19-30 y

22.6

18.7

Table has been converted to the following text.

Phosphorus - Recommended Daily Allowance (RDA) and Estimated Average Requirement (EAR):

1-6 months:

EAR: 3.2 mmol/day (Adequate intake)

7-12 months:

EAR: 8.9 mmol/day (Adequate intake)

1-3 years:

RDA: 14.8 mmol/day

EAR: 12.3 mmol/day

4-8 years:

RDA: 16.1 mmol/day

EAR: 13.1 mmol/day

9-18 years:

RDA: 40.3 mmol/day

EAR: 34 mmol/day

19-30 years:

RDA: 22.6 mmol/day

EAR: 18.7 mmol/day

Hypophosphatemia, acute: Hypophosphatemia does not necessarily equate with phosphate depletion. Hypophosphatemia may occur in the presence of low, normal, or high total body phosphate and conversely, phosphate depletion may exist with normal, low, or elevated levels of serum phosphate (Gaasbeek 2005). It is difficult to provide concrete guidelines for the treatment of severe hypophosphatemia because the extent of total body deficits and response to therapy are difficult to predict. Aggressive doses of phosphate may result in a transient serum elevation followed by redistribution into intracellular compartments or bone tissue. Intermittent IV infusion should be reserved for severe depletion situations; requires continuous cardiac monitoring. Guidelines differ based on degree of illness, need/use of TPN, and severity of hypophosphatemia. If hypokalemia exists, consider phosphate replacement strategy with potassium (eg, potassium phosphates). Various regimens for replacement of phosphate in adults have been studied. The regimens below have only been studied in adult patients; however, many institutions have used them in children safely and successfully. Obese patients and/or severe renal impairment were excluded from phosphate supplement trials. Note: 1 mmol phosphate = 31 mg phosphorus; 1 mg phosphorus = 0.032 mmol phosphate.

IV doses may be incorporated into the patient's maintenance IV fluids; intermittent IV infusion should be reserved for severe depletion situations. Note: Doses listed as mmol of phosphate.

Children and Adolescents: Note: There are no prospective studies of parenteral phosphate replacement in children. The following weight-based guidelines for adult dosing may be cautiously employed in pediatric patients. Guidelines differ based on degree of illness, use of TPN, and severity of hypophosphatemia.

General replacement guidelines (Lentz 1978): Note: The initial dose may be increased by 25% to 50% if the patient is symptomatic secondary to hypophosphatemia and lowered by 25% to 50% if the patient is hypercalcemic.

Low dose: 0.08 mmol/kg over 6 hours; use if losses are recent and uncomplicated

Intermediate dose: 0.16 to 0.24 mmol/kg over 4 to 6 hours; use if serum phosphorus level 0.5 to 1 mg/dL (0.16 to 0.32 mmol/L)

High dose: 0.36 mmol/kg over 6 hours; use if serum phosphorus <0.5 mg/dL (<0.16 mmol/L)

Patients receiving TPN (Clark 1995):

Low dose: 0.16 mmol/kg over 4 to 6 hours; use if serum phosphorus level 2.3 to 3 mg/dL (0.73 to 0.96 mmol/L)

Intermediate dose: 0.32 mmol/kg over 4 to 6 hours; use if serum phosphorus level 1.6 to 2.2 mg/dL (0.51 to 0.72 mmol/L)

High dose: 0.64 mmol/kg over 8 to 12 hours; use if serum phosphorus <1.5 mg/dL (<0.5 mmol/L)

Critically ill adult trauma patients receiving TPN (Brown 2006):

Low dose: 0.32 mmol/kg over 4 to 6 hours; use if serum phosphorus level 2.3 to 3 mg/dL (0.73 to 0.96 mmol/L)

Intermediate dose: 0.64 mmol/kg over 4 to 6 hours; use if serum phosphorus level 1.6 to 2.2 mg/dL (0.51 to 0.72 mmol/L)

High dose: 1 mmol/kg over 8 to 12 hours; use if serum phosphorus <1.5 mg/dL (<0.5 mmol/L)

Alternative method in critically ill patients (Kingston 1985):

Low dose: 0.25 mmol/kg over 4 hours; use if serum phosphorus level 0.5 to 1 mg/dL (0.16 to 0.32 mmol/L)

Moderate dose: 0.5 mmol/kg over 4 hours; use if serum phosphorus level <0.5 mg/dL (<0.16 mmol/L)

Parenteral nutrition, maintenance requirement (Mirtallo 2004): IV:

Infants and Children ≤50 kg: 0.5 to 2 mmol/kg/day

Children >50 kg and Adolescents: 10 to 40 mmol/day

Constipation:

Oral, solution (Monobasic sodium phosphate monohydrate 2.4 g and dibasic sodium phosphate heptahydrate 0.9 g per 5 mL): Note: Must be diluted in a full glass of water:

Children 5 to 9 years: 7.5 mL as a single dose

Children 10 to 11 years: 15 mL as a single dose

Children ≥12 years and Adolescents: 15 mL as a single dose; maximum single daily dose: 45 mL/day

Rectal: Fleet Enema:

Children 2 to 4 years: Administer one half contents of one 2.25 ounce pediatric enema

Children 5 to 11 years: Administer the contents of one 2.25 ounce pediatric enema

Children ≥12 years and Adolescents: Administer the contents of one 4.5 ounce enema as a single dose

Reconstitution

Solution for injection: In general, the dose, concentration of infusion, and rate of administration may be dependent on patient condition and specific institution policy. Intermittent infusion doses are typically prepared in 100-250 mL of NS or D5W (usual concentration range: 0.15-0.6 mmol/mL). Observe the vial for the presence of crystals. Do not use vial if crystals are present.

Administration

IV: Administer by intermittent IV infusion; do not administer IV push. Must be diluted prior to parenteral administration. In general, the dose, concentration of infusion, and rate of administration may be dependent on patient condition and specific institution policy. For patients with severe symptomatic hypophosphatemia (ie, <1.5 mg/dL), may administer at rates up to 15 mmol/hour (Charron 2003; Rosen 1995). In patients with renal dysfunction and/or less severe hypophosphatemia, slower administration rates (eg, over 4 to 6 hours) or oral repletion is recommended.

Bowel cleansing (oral tablets): A clear liquid diet should be used prior to and during tablet administration. Have patient drink 8 ounces of clear liquids with each dose of sodium phosphate; have patient rehydrate before and after colonoscopy. Clear liquids may include water, flavored water, pulp-free lemonade, ginger ale, or apple juice; avoid alcohol, milk, purple or red colored liquids, and pulp-containing foods/liquids. Avoid use of other laxatives during the bowel cleansing and administration of other oral medications within 1 hour before or after each bowel-cleansing tablet. Refer to the manufacturer's labeling and/or the medication guide for additional administration instructions.

Constipation (oral solution): Take on an empty stomach; dilute dose with 8 ounces cool water, then follow dose with 8 ounces water; do not repeat dose within 24 hours

Dietary Considerations

Some products may contain phenylalanine and/or sodium.

Storage

Enema: Store at room temperature.

Oral solution: Store at room temperature.

Solution for injection: Store intact vials at 20°C to 25°C (68°F to 77°F); excursions permitted between 15°C and 30°C (59°F and 86°F).

Tablet: Store at 25°C (77°F); excursions permitted between 15°C and 30°C (59°F and 86°F).

Drug Interactions

Angiotensin II Receptor Blockers: May enhance the nephrotoxic effect of Sodium Phosphates. Specifically, the risk of acute phosphate nephropathy may be enhanced. Management: Consider avoiding this combination by temporarily suspending treatment with ARBs, or seeking alternatives to oral sodium phosphate bowel preparation. If the combination cannot be avoided, maintain adequate hydration and monitor renal function closely. Consider therapy modification

Angiotensin-Converting Enzyme Inhibitors: May enhance the nephrotoxic effect of Sodium Phosphates. Specifically, the risk of acute phosphate nephropathy may be enhanced. Management: Consider avoiding this combination by temporarily suspending treatment with ACEIs, or seeking alternatives to oral sodium phosphate bowel preparation. If the combination cannot be avoided, maintain adequate hydration and monitor renal function closely. Consider therapy modification

Antacids: May decrease the absorption of Phosphate Supplements. Management: This applies only to oral phosphate administration. Separating administer of oral phosphate supplements from antacid administration by as long as possible may minimize the interaction. Consider therapy modification

Burosumab-twza: Phosphate Supplements may enhance the adverse/toxic effect of Burosumab-twza. Avoid combination

Calcium Salts: May decrease the absorption of Phosphate Supplements. Management: This applies only to oral phosphate and calcium administration. Administering oral phosphate supplements as far apart from the administration of an oral calcium salt as possible may be able to minimize the significance of the interaction. Consider therapy modification

Diuretics: May enhance the nephrotoxic effect of Sodium Phosphates. Specifically, the risk of acute phosphate nephropathy may be enhanced. Management: Consider avoiding this combination by temporarily suspending treatment with diuretics, or seeking alternatives to oral sodium phosphate bowel preparation. If the combination cannot be avoided, hydrate adequately and monitor fluid and renal status. Consider therapy modification

Iron Salts: May decrease the absorption of Phosphate Supplements. Management: Administer oral phosphate supplements as far apart from the administration of an oral iron salt as possible to minimize the significance of this interaction. Exceptions: Ferric Carboxymaltose; Ferric Gluconate; Ferric Hydroxide Polymaltose Complex; Ferric Pyrophosphate Citrate; Ferumoxytol; Iron Dextran Complex; Iron Isomaltoside; Iron Sucrose. Consider therapy modification

Magnesium Salts: May decrease the serum concentration of Phosphate Supplements. Management: Administer oral phosphate supplements as far apart from the administration of an oral magnesium salt as possible to minimize the significance of this interaction. Consider therapy modification

Multivitamins/Minerals (with ADEK, Folate, Iron): May decrease the serum concentration of Phosphate Supplements. Management: Administer oral phosphate supplements as far apart from the administration of an iron-containing oral multivitamin as possible to minimize the significance of this interaction. Consider therapy modification

Nonsteroidal Anti-Inflammatory Agents: Sodium Phosphates may enhance the nephrotoxic effect of Nonsteroidal Anti-Inflammatory Agents. Specifically, the risk of acute phosphate nephropathy may be enhanced. Management: Consider avoiding this combination by temporarily suspending treatment with NSAIDs, or seeking alternatives to oral sodium phosphate bowel preparation. If the combination cannot be avoided, maintain adequate hydration and monitor renal function closely. Consider therapy modification

Sucralfate: May decrease the absorption of Phosphate Supplements. Management: This applies only to oral phosphate administration. Administering oral phosphate supplements at least 1 hour before or 2 hours after administration of sucralfate may reduce the significance of the interaction. Consider therapy modification

Tricyclic Antidepressants: May enhance the adverse/toxic effect of Sodium Phosphates. Specifically, the risk of seizure and/or loss of consciousness may be increased in patients with significant sodium phosphate induced fluid/electrolyte abnormalities. Monitor therapy

Adverse Reactions

>10%:

Gastrointestinal: Bloating (31%), nausea (26%), abdominal pain (23%)

Endocrine & metabolic: Hyperphosphatemia (≤96%), hypokalemia (on colonoscopy day; 18% to 22%)

1% to 10%: Gastrointestinal: Vomiting (4%), aphthous stomatitis (3%)

Postmarketing and/or case reports: Anaphylaxis, angioedema, bronchospasm, calcium nephrolithiasis, cardiac arrhythmia, dysphagia, dyspnea, facial edema, hypernatremia, hypersensitivity reaction, hypocalcemia, increased blood urea nitrogen, increased serum creatinine, lip edema, paresthesia, pharyngeal edema, pruritus, renal disease (acute phosphate), renal failure syndrome, renal insufficiency, renal tubular necrosis, seizure, skin rash, tongue edema, urticaria

ALERT: U.S. Boxed Warning

Nephropathy (tablet):

There have been rare but serious reports of acute phosphate nephropathy in patients who received oral sodium phosphate products for colon cleansing prior to colonoscopy. Some cases have resulted in permanent impairment of renal function and some patients required long-term dialysis. While some cases have occurred in patients without identifiable risk factors, patients at increased risk of acute phosphate nephropathy may include those with increased age, hypovolemia, increased bowel transit time (such as bowel obstruction), active colitis, or baseline kidney disease, and those using medicines that affect renal perfusion or function (such as diuretics, angiotensin-converting enzyme [ACE] inhibitors, angiotensin receptor blockers, and possibly nonsteroidal anti-inflammatory drugs [NSAIDs]).

Advise patients of the importance of following the recommended split dosage regimen and the importance of adequate hydration before, during, and after use of oral sodium phosphate products. Avoid additional sodium phosphate–based purgative or enema products.

Warnings/Precautions

Concerns related to adverse effects:

• Hypersensitivity: Serious reactions, including anaphylaxis, have been reported.

• Nephropathy: [US Boxed Warning]: Acute phosphate nephropathy (APN) has been reported (rarely) with use of oral products as a colon cleanser prior to colonoscopy. Some cases have resulted in permanent renal impairment (some requiring dialysis). Risk factors for acute phosphate nephropathy may include increased age (>55 years of age), preexisting renal dysfunction, bowel obstruction, active colitis, or dehydration, and the use of medicines that affect renal perfusion or function (eg, ACE inhibitors, angiotensin receptor blockers, diuretics, and possibly NSAIDs), although some cases have been reported in patients without apparent risk factors. Advise patients of the importance of following the recommended split dosage regimen and the importance of adequate hydration before, during and after use of oral sodium phosphate products. Avoid additional sodium phosphate-based purgative or enema products. Obtain baseline and postprocedure labs in patients at risk of nephropathy; consider hospitalization and intravenous hydration during bowel cleansing for patients unable to hydrate themselves (eg, frail patients). Use is contraindicated in patients with acute phosphate nephropathy. APN has also been reported (rarely) following the use of sodium phosphate enemas. This has been primarily observed in elderly patients with and without preexisting renal impairment and with those receiving standard or doses exceeding usual doses (Ori 2012).

• QT prolongation: Prolongation of the QT interval has been reported (associated with hypokalemia, hypocalcemia).

Disease-related concerns:

• Cardiovascular: Use caution in patients with heart failure (contraindicated with enema products), unstable angina, history of myocardial infarction arrhythmia, cardiomyopathy; use caution in patients with or at risk for arrhythmias (eg, cardiomyopathy, prolonged QT interval, history of uncontrolled arrhythmias, recent MI) or with concurrent use of other QT-prolonging medications; pre-/postdose ECGs and lab tests should be considered in high-risk patients.

• Electrolyte disturbances: Fluid and electrolyte disturbances may occur. Use with caution in patients with preexisting electrolyte imbalances, dehydration, or risk of electrolyte disturbance (hypocalcemia, hyperphosphatemia, hypernatremia); obtain baseline and postprocedure labs in high-risk patients. Correct dehydration prior to using for bowel preparations.

• GI disorders: Use caution in patients with any of the following: Gastric retention or hypomotility, ileus, severe, chronic constipation, or severe active ulcerative colitis. Use is contraindicated in patients with bowel obstruction (including pseudo) or perforation, congenital megacolon, gastric bypass or bariatric surgery, toxic colitis, or toxic megacolon.

• Inflammatory bowel disease: Use with caution in patients with an acute exacerbation of chronic inflammatory bowel disease; phosphate absorption may be increased. Oral sodium phosphate products may induce colonic aphthous ulceration, which should be considered when interpreting colonoscopic findings in patients with inflammatory bowel disease.

• Renal impairment: Use with caution in patients with renal impairment; patients may be at risk for sodium retention and edema. Close monitoring required to avoid hyperphosphatemia. Obtain baseline and postprocedure labs in patients with renal impairment.

• Seizure disorder: Use with caution in patients with a history of seizures, those at higher risk of seizures or on medication that lowers seizure threshold; obtain baseline and postprocedure labs in high-risk patients.

Special populations:

• Bulimia nervosa patients: Laxatives and purgatives have the potential for abuse by bulimia nervosa patients.

• Debilitated patients: Use with caution in debilitated patients; consider each patient's ability to hydrate properly.

• Elderly: Use with caution in elderly patients; ensure they are able to hydrate themselves if using for bowel preparation.

• Impaired gag reflex: Use with caution in patients with impaired gag reflex and those prone to regurgitation or aspiration.

Dosage form specific issues:

• Aluminum: The parenteral product may contain aluminum; toxic aluminum concentrations may be seen with high doses, prolonged use, or renal dysfunction. Premature neonates are at higher risk due to immature renal function and aluminum intake from other parenteral sources. Parenteral aluminum exposure of >4 to 5 mcg/kg/day is associated with CNS and bone toxicity; tissue loading may occur at lower doses (Federal Register 2002). See manufacturer's labeling.

• Benzyl alcohol and derivatives: Some dosage forms may contain sodium benzoate/benzoic acid; benzoic acid (benzoate) is a metabolite of benzyl alcohol; large amounts of benzyl alcohol (≥99 mg/kg/day) have been associated with a potentially fatal toxicity ("gasping syndrome") in neonates; the "gasping syndrome" consists of metabolic acidosis, respiratory distress, gasping respirations, CNS dysfunction (including convulsions, intracranial hemorrhage), hypotension, and cardiovascular collapse (AAP ["Inactive" 1997]; CDC 1982); some data suggests that benzoate displaces bilirubin from protein binding sites (Ahlfors 2001); avoid or use dosage forms containing benzyl alcohol derivative with caution in neonates. See manufacturer's labeling.

• Enemas/oral solutions: Available in pediatric and adult sizes; prescribe by "volume" not by "bottle."

Other warnings/precautions:

• Bowel evacuation: Appropriate use: If using as a bowel evacuant, correct electrolyte abnormalities before administration. Ensure adequate clear liquid intake prior to and during bowel evacuation regimens; inadequate fluid intake may lead to excessive fluid loss and hypovolemia. Other oral medications may not be well absorbed when given during bowel evacuation because of rapid intestinal peristalsis.

• Constipation: Appropriate use: Rare but potentially serious adverse effects (including death) may occur when exceeding recommended doses of over-the-counter (OTC) sodium phosphate preparations to treat constipation. Severe dehydration and alterations in serum electrolytes (eg, calcium, sodium, phosphate) leading to renal/cardiac adverse effects have been reported, mostly when single maximum doses were exceeded or when more than 1 dose was taken per day. Patients should be advised to adhere to the product labeling and not exceed maximum recommended doses. Health care providers should use caution when recommending doses for oral sodium phosphate preparations for children younger than 5 years of age. Rectal preparations should never be administered to children younger than 2 years of age (FDA Drug Safety Communication 2014).

Monitoring Parameters

IV: Serum calcium, sodium and phosphorus levels; renal function; after IV phosphate repletion, repeat serum phosphorus level should be checked 2-4 hours later

Oral: Bowel cleansing: Baseline and postprocedure labs (electrolytes, calcium, phosphorus, BUN, creatinine) in patients with renal impairment or who are taking medications or with conditions that increase the risk of fluid and electrolyte abnormalities, seizures, arrhythmias, or renal impairment; ECG in patients with risks for prolonged QT or arrhythmias. Ensure euvolemia before initiating bowel preparation.

Pregnancy Considerations

Reproduction studies have not been conducted with these products. Use with caution in pregnant women.

Patient Education

• Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)

• Have patient report immediately to prescriber signs of fluid and electrolyte problems (mood changes, confusion, muscle pain or weakness, abnormal heartbeat, severe dizziness, passing out, tachycardia, increased thirst, seizures, loss of strength and energy, lack of appetite, urinary retention or change in amount of urine passed, dry mouth, dry eyes, or nausea or vomiting); signs of kidney problems (urinary retention, hematuria, change in amount of urine passed, or weight gain); severe abdominal cramps or bloating; severe abdominal pain; severe headache; severe nausea; vomiting; black, tarry, or bloody stools; rectal pain or bleeding; or angina (HCAHPS).

• Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.

Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for health care professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience, and judgment in diagnosing, treating, and advising patients.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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