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  • CLASSES

    Acidifying Agents
    Phosphorous Supplements

    DEA CLASS

    Rx, OTC

    DESCRIPTION

    Phosphorus supplement for the dietary management of hypophosphatemia
    Also used for urinary acidification and to augment the efficacy of methenamine therapy in treating urinary tract infections
    Treatment initiation may cause a persistent laxation effect in some patients and can cause patients with kidney stones to pass old stones

    COMMON BRAND NAMES

    Av-Phos, K-Phos Neutral, Phos-NaK, Phospha 250 Neutral, Virt-Phos 250 Neutral

    HOW SUPPLIED

    Av-Phos/K-Phos Neutral/Phospha 250 Neutral/Potassium Phosphate, Monobasic, Sodium Phosphate, Dibasic, Sodium Phosphate, Monobasic/Virt-Phos 250 Neutral Oral Tab
    Phos-NaK/Potassium Phosphate, Dibasic, Sodium Phosphate, Monobasic Oral Pwd F/Recon

    DOSAGE & INDICATIONS

    For the dietary management of hypophosphatemia or phosphorus nutritional supplementation.
    Oral dosage (tablets)
    Adults

    1 or 2 tablets (250 to 500 mg phosphorus) PO four times daily with meals and at bedtime. The US RDA for phosphorus is 1,250 mg for adults 18 years of age and 700 mg for adults 19 years and older.

    Adolescents and Children 4 years and older

    1 tablet (250 mg phosphorus) PO four times daily with meals and at bedtime. The US RDA for phosphorus is 500 mg for children 4 to 8 years and 1,250 mg for children and adolescents 9 to 17 years.

    Oral dosage (powder for oral solution)
    Adults

    1 packet (250 mg phosphorus) PO four times daily. The US RDA for phosphorus is 1,250 mg for adults 18 years of age and 700 mg for adults 19 years and older.

    Adolescents and Children 4 years and older

    1 packet (250 mg phosphorus) PO 4 four times daily. The US RDA for phosphorus is 500 mg for children 4 to 8 years and 1,250 mg for children and adolescents 9 to 17 years.

    MAXIMUM DOSAGE

    Adults

    8 tablets (2,000 mg phosphorus) or 4 packets (1,000 mg phosphorus) PO per day.

    Geriatric

    8 tablets (2,000 mg phosphorus) or 4 packets (1,000 mg phosphorus) PO per day.

    Adolescents

    4 tablets or packets (1,000 mg phosphorus) PO per day.

    Children

    4 to 12 years: 4 tablets or packets (1,000 mg phosphorus) PO per day.
    1 to 3 years: Safety and efficacy have not been established.

    Infants

    Safety and efficacy have not been established.

    Neonates

    Safety and efficacy have not been established.

    DOSING CONSIDERATIONS

    Hepatic Impairment

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

    Renal Impairment

    Specific guidelines for dosage adjustments in renal impairment are not available. Do not administer to patients with severely impaired renal function (which the manufacturer defines as less than 30% of normal).[57715] [65784]

    STORAGE

    Av-Phos:
    - Protect from light
    - Protect from moisture
    - Store between 68 to 77 degrees F, excursions permitted 59 to 86 degrees F
    K-Phos Neutral:
    - Protect from light
    - Protect from moisture
    - Store between 68 to 77 degrees F, excursions permitted 59 to 86 degrees F
    Neutra-Phos:
    - Store in a dry place
    Phos-NaK :
    - Protect from light
    - Protect from moisture
    - Store at controlled room temperature (between 68 and 77 degrees F)
    Phospha 250 Neutral:
    - Protect from light
    - Protect from moisture
    - Store between 68 to 77 degrees F, excursions permitted 59 to 86 degrees F
    Uro-Kp-Neutral:
    - Storage information not listed
    Virt-Phos 250 Neutral:
    - Protect from light
    - Protect from moisture
    - Store between 68 to 77 degrees F, excursions permitted 59 to 86 degrees F

    CONTRAINDICATIONS / PRECAUTIONS

    Renal disease, renal failure, renal impairment

    Potassium phosphate; sodium phosphate is contraindicated in patients with renal failure or with severely impaired renal function (less than 30% of normal). Exercise caution with use in patients who have severe renal insufficiency, renal impairment, or chronic renal disease. Careful monitoring of renal function may be required at periodic intervals during phosphate therapy.

    Infection, nephrolithiasis

    Potassium phosphate; sodium phosphate is contraindicated in patients who have a phosphate nephrolithiasis infection (i.e., infected phosphate stones). Patients with kidney stones may pass old stones when phosphate therapy is started and should be warned of this possibility.

    Dehydration, hyperkalemia, hypernatremia, hyperphosphatemia, sodium restriction

    Potassium phosphate; sodium phosphate administration is contraindicated in patients with hyperphosphatemia. High serum phosphate concentrations may increase the incidence of extraskeletal calcification. Caution should be exercised when considering use in patients with acute dehydration, hypernatremia, or hyperkalemia. This product contains potassium and sodium and should be used with caution if potassium or sodium restriction is desired. Careful monitoring of serum calcium, phosphorus, potassium, and sodium may be required at periodic intervals during phosphate therapy.[57715] [65784]

    Cardiac disease, heart failure, hypertension, peripheral edema

    Exercise caution when considering the use of potassium phosphate; sodium phosphate in patients who have cardiac disease (particularly in digitalized patients), heart failure, hypertension, or peripheral edema.

    Hepatic disease

    Use potassium phosphate; sodium phosphate with caution in patients who have severe hepatic disease and cirrhosis of the liver.

    Osteomalacia

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

    Burns

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

    Adrenal insufficiency, hypoparathyroidism, pancreatitis, pulmonary edema

    Use caution when considering potassium phosphate; sodium phosphate in patients who have severe adrenal insufficiency (Addison's disease), myotonia congenita, pulmonary edema, hypoparathyroidism, or acute pancreatitis.

    Preeclampsia, pregnancy

    Animal reproduction studies have not been conducted with potassium phosphate; sodium phosphate. It is unknown whether phosphorus salts can cause fetal harm when administered to a pregnant woman. Potassium phosphate; sodium phosphate should only be administered during pregnancy if clearly needed. Exercise caution when considering administration to a patient with preeclampsia, as sodium-containing phosphorus salts may exacerbate toxemia of pregnancy.[57715]

    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 with potassium phosphate; sodium phosphate, when required, on the infant during breast-feeding.

    ADVERSE REACTIONS

    Severe

    seizures / Delayed / Incidence not known
    oliguria / Early / Incidence not known

    Moderate

    bone pain / Delayed / Incidence not known
    osteomalacia / Delayed / Incidence not known
    neuropathic pain / Delayed / Incidence not known
    confusion / Early / Incidence not known
    nephrolithiasis / Delayed / Incidence not known
    dyspnea / Early / Incidence not known
    peripheral edema / Delayed / Incidence not known

    Mild

    diarrhea / Early / Incidence not known
    vomiting / Early / Incidence not known
    weight gain / Delayed / Incidence not known
    nausea / Early / Incidence not known
    abdominal pain / Early / Incidence not known
    arthralgia / Delayed / Incidence not known
    weakness / Early / Incidence not known
    paresthesias / Delayed / Incidence not known
    muscle cramps / Delayed / Incidence not known
    dizziness / Early / Incidence not known
    headache / Early / Incidence not known
    polydipsia / Early / Incidence not known

    DRUG INTERACTIONS

    Acetaminophen; Aspirin, ASA; Caffeine: (Moderate) Acidification of the urine may increase serum concentrations of salicylates by increasing tubular reabsorption of salicylates, however, this interaction is not likely to be clinically significant since the urine is normally acidic. (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
    Acetaminophen; Caffeine; Magnesium Salicylate; Phenyltoloxamine: (Moderate) Acidification of the urine may increase serum concentrations of salicylates by increasing tubular reabsorption of salicylates, however, this interaction is not likely to be clinically significant since the urine is normally acidic.
    Alendronate; Cholecalciferol: (Major) High intake of phosphates concomitantly with vitamin D or vitamin D analogs may lead to hyperphosphatemia. Dose adjustment of vitamin D or vitamin D analogs may be necessary during coadministration with phosphorus salts. Additionally, serum calcium concentrations should be monitored frequently. Monitor more frequently in patients with a history of hypercalcemia.
    Aliskiren; Valsartan: (Major) Avoid coadministration of potassium phosphate and angiotensin II receptor antagonists as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Aluminum Hydroxide: (Major) Aluminum hydroxide and magnesium hydroxide (as well as other antacids, i.e. aluminum hydroxide; magnesium carbonate, aluminum hydroxide; magaldrate; magnesium hydroxide, and aluminum hydroxide; magnesium trisilicate) may interact with urinary acidifiers by alkalinizing the urine. Frequent use of these high dose antacids should be avoided in patients receiving urinary acidifiers. (Moderate) The oral absorption of phosphorus is reduced by ingestion of aluminum-containing antacids (e.g., aluminum hydroxide). If the patient requires treatment with aluminum-containing antacids, it may be wise to separate the administration of phosphorus salts from the antacid. In some instances the administration of an aluminum hydroxide product is used therapeutically (e.g., uremia) to decrease serum phosphorus levels, so the administration of phosphorus supplements would dynamically counteract the intended use of these drugs in these settings, assuming hypophosphatemia is not present.
    Aluminum Hydroxide; Magnesium Carbonate: (Major) Aluminum hydroxide and magnesium hydroxide (as well as other antacids, i.e. aluminum hydroxide; magnesium carbonate, aluminum hydroxide; magaldrate; magnesium hydroxide, and aluminum hydroxide; magnesium trisilicate) may interact with urinary acidifiers by alkalinizing the urine. Frequent use of these high dose antacids should be avoided in patients receiving urinary acidifiers. (Moderate) Phosphate may bind magnesium salts and magnesium-containing antacids (e.g., magnesium carbonate, magnesium hydroxide) may limit phosphorus absorption or phosphorus may limit magnesium absorption. If the patient requires magnesium supplements or a magnesium-containing antacid, it may be wise to separate the administration of phosphates from magnesium-containing products. (Moderate) The oral absorption of phosphorus is reduced by ingestion of aluminum-containing antacids (e.g., aluminum hydroxide). If the patient requires treatment with aluminum-containing antacids, it may be wise to separate the administration of phosphorus salts from the antacid. In some instances the administration of an aluminum hydroxide product is used therapeutically (e.g., uremia) to decrease serum phosphorus levels, so the administration of phosphorus supplements would dynamically counteract the intended use of these drugs in these settings, assuming hypophosphatemia is not present.
    Aluminum Hydroxide; Magnesium Hydroxide: (Major) Aluminum hydroxide and magnesium hydroxide (as well as other antacids, i.e. aluminum hydroxide; magnesium carbonate, aluminum hydroxide; magaldrate; magnesium hydroxide, and aluminum hydroxide; magnesium trisilicate) may interact with urinary acidifiers by alkalinizing the urine. Frequent use of these high dose antacids should be avoided in patients receiving urinary acidifiers. (Moderate) Phosphate may bind magnesium salts and magnesium-containing antacids (e.g., magnesium carbonate, magnesium hydroxide) may limit phosphorus absorption or phosphorus may limit magnesium absorption. If the patient requires magnesium supplements or a magnesium-containing antacid, it may be wise to separate the administration of phosphates from magnesium-containing products. (Moderate) The oral absorption of phosphorus is reduced by ingestion of aluminum-containing antacids (e.g., aluminum hydroxide). If the patient requires treatment with aluminum-containing antacids, it may be wise to separate the administration of phosphorus salts from the antacid. In some instances the administration of an aluminum hydroxide product is used therapeutically (e.g., uremia) to decrease serum phosphorus levels, so the administration of phosphorus supplements would dynamically counteract the intended use of these drugs in these settings, assuming hypophosphatemia is not present.
    Aluminum Hydroxide; Magnesium Hydroxide; Simethicone: (Major) Aluminum hydroxide and magnesium hydroxide (as well as other antacids, i.e. aluminum hydroxide; magnesium carbonate, aluminum hydroxide; magaldrate; magnesium hydroxide, and aluminum hydroxide; magnesium trisilicate) may interact with urinary acidifiers by alkalinizing the urine. Frequent use of these high dose antacids should be avoided in patients receiving urinary acidifiers. (Moderate) Phosphate may bind magnesium salts and magnesium-containing antacids (e.g., magnesium carbonate, magnesium hydroxide) may limit phosphorus absorption or phosphorus may limit magnesium absorption. If the patient requires magnesium supplements or a magnesium-containing antacid, it may be wise to separate the administration of phosphates from magnesium-containing products. (Moderate) The oral absorption of phosphorus is reduced by ingestion of aluminum-containing antacids (e.g., aluminum hydroxide). If the patient requires treatment with aluminum-containing antacids, it may be wise to separate the administration of phosphorus salts from the antacid. In some instances the administration of an aluminum hydroxide product is used therapeutically (e.g., uremia) to decrease serum phosphorus levels, so the administration of phosphorus supplements would dynamically counteract the intended use of these drugs in these settings, assuming hypophosphatemia is not present.
    Aluminum Hydroxide; Magnesium Trisilicate: (Major) Aluminum hydroxide and magnesium hydroxide (as well as other antacids, i.e. aluminum hydroxide; magnesium carbonate, aluminum hydroxide; magaldrate; magnesium hydroxide, and aluminum hydroxide; magnesium trisilicate) may interact with urinary acidifiers by alkalinizing the urine. Frequent use of these high dose antacids should be avoided in patients receiving urinary acidifiers. (Moderate) The oral absorption of phosphorus is reduced by ingestion of aluminum-containing antacids (e.g., aluminum hydroxide). If the patient requires treatment with aluminum-containing antacids, it may be wise to separate the administration of phosphorus salts from the antacid. In some instances the administration of an aluminum hydroxide product is used therapeutically (e.g., uremia) to decrease serum phosphorus levels, so the administration of phosphorus supplements would dynamically counteract the intended use of these drugs in these settings, assuming hypophosphatemia is not present.
    Amiloride: (Major) Avoid coadministration of potassium phosphate and potassium-sparing diuretics as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Amiloride; Hydrochlorothiazide, HCTZ: (Major) Avoid coadministration of potassium phosphate and potassium-sparing diuretics as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Amlodipine; Benazepril: (Major) Avoid coadministration of potassium phosphate and angiotensin-converting enzyme inhibitors as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Amlodipine; Hydrochlorothiazide, HCTZ; Olmesartan: (Major) Avoid coadministration of potassium phosphate and angiotensin II receptor antagonists as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Amlodipine; Hydrochlorothiazide, HCTZ; Valsartan: (Major) Avoid coadministration of potassium phosphate and angiotensin II receptor antagonists as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Amlodipine; Olmesartan: (Major) Avoid coadministration of potassium phosphate and angiotensin II receptor antagonists as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Amlodipine; Telmisartan: (Major) Avoid coadministration of potassium phosphate and angiotensin II receptor antagonists as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Amlodipine; Valsartan: (Major) Avoid coadministration of potassium phosphate and angiotensin II receptor antagonists as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Angiotensin II receptor antagonists: (Major) Avoid coadministration of potassium phosphate and angiotensin II receptor antagonists as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Angiotensin-converting enzyme inhibitors: (Major) Avoid coadministration of potassium phosphate and angiotensin-converting enzyme inhibitors as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Antacids: (Major) Aluminum hydroxide and magnesium hydroxide (as well as other antacids, i.e. aluminum hydroxide; magnesium carbonate, aluminum hydroxide; magaldrate; magnesium hydroxide, and aluminum hydroxide; magnesium trisilicate) may interact with urinary acidifiers by alkalinizing the urine. Frequent use of these high dose antacids should be avoided in patients receiving urinary acidifiers.
    Aspirin, ASA: (Moderate) Acidification of the urine may increase serum concentrations of salicylates by increasing tubular reabsorption of salicylates, however, this interaction is not likely to be clinically significant since the urine is normally acidic. (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
    Aspirin, ASA; Butalbital; Caffeine: (Moderate) Acidification of the urine may increase serum concentrations of salicylates by increasing tubular reabsorption of salicylates, however, this interaction is not likely to be clinically significant since the urine is normally acidic. (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
    Aspirin, ASA; Butalbital; Caffeine; Codeine: (Moderate) Acidification of the urine may increase serum concentrations of salicylates by increasing tubular reabsorption of salicylates, however, this interaction is not likely to be clinically significant since the urine is normally acidic. (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
    Aspirin, ASA; Caffeine: (Moderate) Acidification of the urine may increase serum concentrations of salicylates by increasing tubular reabsorption of salicylates, however, this interaction is not likely to be clinically significant since the urine is normally acidic. (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
    Aspirin, ASA; Caffeine; Dihydrocodeine: (Moderate) Acidification of the urine may increase serum concentrations of salicylates by increasing tubular reabsorption of salicylates, however, this interaction is not likely to be clinically significant since the urine is normally acidic. (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
    Aspirin, ASA; 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. (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
    Aspirin, ASA; Carisoprodol: (Moderate) Acidification of the urine may increase serum concentrations of salicylates by increasing tubular reabsorption of salicylates, however, this interaction is not likely to be clinically significant since the urine is normally acidic. (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
    Aspirin, ASA; Carisoprodol; Codeine: (Moderate) Acidification of the urine may increase serum concentrations of salicylates by increasing tubular reabsorption of salicylates, however, this interaction is not likely to be clinically significant since the urine is normally acidic. (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
    Aspirin, ASA; 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. (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
    Aspirin, ASA; Dipyridamole: (Moderate) Acidification of the urine may increase serum concentrations of salicylates by increasing tubular reabsorption of salicylates, however, this interaction is not likely to be clinically significant since the urine is normally acidic. (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
    Aspirin, ASA; Omeprazole: (Moderate) Acidification of the urine may increase serum concentrations of salicylates by increasing tubular reabsorption of salicylates, however, this interaction is not likely to be clinically significant since the urine is normally acidic. (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
    Aspirin, ASA; Oxycodone: (Moderate) Acidification of the urine may increase serum concentrations of salicylates by increasing tubular reabsorption of salicylates, however, this interaction is not likely to be clinically significant since the urine is normally acidic. (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
    Aspirin, ASA; Pravastatin: (Moderate) Acidification of the urine may increase serum concentrations of salicylates by increasing tubular reabsorption of salicylates, however, this interaction is not likely to be clinically significant since the urine is normally acidic. (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
    Azelastine; Fluticasone: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Azilsartan: (Major) Avoid coadministration of potassium phosphate and angiotensin II receptor antagonists as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Azilsartan; Chlorthalidone: (Major) Avoid coadministration of potassium phosphate and angiotensin II receptor antagonists as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Beclomethasone: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Benazepril: (Major) Avoid coadministration of potassium phosphate and angiotensin-converting enzyme inhibitors as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Benazepril; Hydrochlorothiazide, HCTZ: (Major) Avoid coadministration of potassium phosphate and angiotensin-converting enzyme inhibitors as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Betamethasone: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Bismuth Subsalicylate: (Moderate) Acidification of the urine may increase serum concentrations of salicylates by increasing tubular reabsorption of salicylates, however, this interaction is not likely to be clinically significant since the urine is normally acidic. (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
    Bismuth Subsalicylate; Metronidazole; Tetracycline: (Moderate) Acidification of the urine may increase serum concentrations of salicylates by increasing tubular reabsorption of salicylates, however, this interaction is not likely to be clinically significant since the urine is normally acidic. (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
    Budesonide: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Budesonide; Formoterol: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Budesonide; Glycopyrrolate; Formoterol: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Burosumab: (Contraindicated) Oral phosphates are contraindicated in patients receiving burosumab; discontinue potassium phosphate 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: (Moderate) The oral absorption of phosphorus is reduced by ingestion of pharmacologic doses of calcium carbonate or other phosphate-lowering calcium salts (e.g., calcium acetate). There is, however, no significant interference with phosphorus absorption by oral dietary calcium at intakes within the typical adult range. If the patient requires multiple calcium supplements or a calcium-containing antacid, it may be wise to separate the administration of phosphorus salts from calcium-containing products. In some instances the administration of calcium salts or calcium carbonate is used therapeutically (e.g., uremia) to decrease serum phosphorus levels, so the administration of phosphorus supplements would dynamically counteract the intended use of calcium in these settings, assuming hypophosphatemia is not present. Appropriate calcium-phosphorus ratios in vivo are important for proper calcium homeostasis in tissues and bone; if the serum ionized calcium concentration is elevated, the concomitant use of calcium salts and phosphorus salts may increase the risk of calcium deposition in soft tissue.
    Calcium; Vitamin D: (Major) High intake of phosphates concomitantly with vitamin D or vitamin D analogs may lead to hyperphosphatemia. Dose adjustment of vitamin D or vitamin D analogs may be necessary during coadministration with phosphorus salts. Additionally, serum calcium concentrations should be monitored frequently. Monitor more frequently in patients with a history of hypercalcemia.
    Candesartan: (Major) Avoid coadministration of potassium phosphate and angiotensin II receptor antagonists as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Candesartan; Hydrochlorothiazide, HCTZ: (Major) Avoid coadministration of potassium phosphate and angiotensin II receptor antagonists as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Captopril: (Major) Avoid coadministration of potassium phosphate and angiotensin-converting enzyme inhibitors as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Captopril; Hydrochlorothiazide, HCTZ: (Major) Avoid coadministration of potassium phosphate and angiotensin-converting enzyme inhibitors as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Carbetapentane; Guaifenesin; Phenylephrine: (Minor) It has been reported that high intakes of phosphates, such as are found in dietary supplements or food additives, can interfere with absorption of trace nutrients such as iron, copper, and zinc. The magnitude of the effect may be small, and the interactions require further study to judge clinical significance. The theorized mechanism is the formation of insoluble complexes within the gut. Until more data are available, it may be helpful to separate administration times of potassium phosphate; sodium phosphateby as much as possible from the oral administration of iron (e.g., iron salts or polysaccharide-iron complex), copper salts, or zinc salts to limit any potential interactions.
    Carbetapentane; Phenylephrine: (Minor) It has been reported that high intakes of phosphates, such as are found in dietary supplements or food additives, can interfere with absorption of trace nutrients such as iron, copper, and zinc. The magnitude of the effect may be small, and the interactions require further study to judge clinical significance. The theorized mechanism is the formation of insoluble complexes within the gut. Until more data are available, it may be helpful to separate administration times of potassium phosphate; sodium phosphateby as much as possible from the oral administration of iron (e.g., iron salts or polysaccharide-iron complex), copper salts, or zinc salts to limit any potential interactions.
    Chlorpheniramine; Pseudoephedrine: (Minor) It has been reported that high intakes of phosphates, such as are found in dietary supplements or food additives, can interfere with absorption of trace nutrients such as iron, copper, and zinc. The magnitude of the effect may be small, and the interactions require further study to judge clinical significance. The theorized mechanism is the formation of insoluble complexes within the gut. Until more data are available, it may be helpful to separate administration times of potassium phosphate; sodium phosphateby as much as possible from the oral administration of iron (e.g., iron salts or polysaccharide-iron complex), copper salts, or zinc salts to limit any potential interactions.
    Choline Salicylate; Magnesium Salicylate: (Moderate) Acidification of the urine may increase serum concentrations of salicylates by increasing tubular reabsorption of salicylates, however, this interaction is not likely to be clinically significant since the urine is normally acidic.
    Ciclesonide: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Colchicine: (Moderate) Colchicine is an alkaloid that is inhibited by acidifying agents. The colchicine dose may need adjustment
    Colchicine; Probenecid: (Moderate) Colchicine is an alkaloid that is inhibited by acidifying agents. The colchicine dose may need adjustment
    Colestipol: (Moderate) Colestipol may interfere with the oral absorption of phosphorus salts. According to the manufacturer, administer other drugs at least 1 hour before or at least 4-6 hours after the administration of colestipol. The manufacturer also recommends that the interval between the administration of colestipol and other drugs should be as long as possible.
    Corticosteroids: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Cortisone: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Cyclosporine: (Major) Avoid coadministration of potassium phosphate and cyclosporine as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Deflazacort: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Dexamethasone: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Diazoxide: (Moderate) Use sodium phosphates cautiously with diazoxide, as concurrent use can cause hypernatremia.
    Dichlorphenamide: (Moderate) Use dichlorphenamide and sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous together with caution. Dichlorphenamide increases potassium excretion and can cause hypokalemia and should be used cautiously with other drugs that may cause hypokalemia including laxatives. Measure potassium concentrations at baseline and periodically during dichlorphenamide treatment. If hypokalemia occurs or persists, consider reducing the dichlorphenamide dose or discontinuing dichlorphenamide therapy.
    Diflunisal: (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
    Digoxin: (Major) Avoid coadministration of potassium phosphate and digoxin as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Enalapril, Enalaprilat: (Major) Avoid coadministration of potassium phosphate and angiotensin-converting enzyme inhibitors as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Enalapril; Felodipine: (Major) Avoid coadministration of potassium phosphate and angiotensin-converting enzyme inhibitors as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Enalapril; Hydrochlorothiazide, HCTZ: (Major) Avoid coadministration of potassium phosphate and angiotensin-converting enzyme inhibitors as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Eplerenone: (Contraindicated) Eplerenone should not be used concomitantly with potassium supplements (including dietary salt substitutes containing potassium) because of the increased risk of developing hyperkalemia. The use of eplerenone in hypertensive patients treated with these medications is contraindicated. When medically necessary to replace losses, use potassium phosphates cautiously with eplerenone, as both drugs increase serum potassium concentrations. Those at risk for hyperkalemia include elderly patients or patients with impaired renal function. Patients at risk for hyperkalemia include elderly patients or patients with impaired renal function. Patients should have serum potassium and other electrolyte concentration determinations at periodic intervals.
    Eprosartan: (Major) Avoid coadministration of potassium phosphate and angiotensin II receptor antagonists as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Eprosartan; Hydrochlorothiazide, HCTZ: (Major) Avoid coadministration of potassium phosphate and angiotensin II receptor antagonists as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Erdafitinib: (Major) Avoid coadministration of potassium phosphate with erdafitinib before the initial dose increase period (days 14 to 21) which is based on serum phosphate levels. Potassium phosphate increases serum phosphate levels. Erdafitinib causes hyperphosphatemia as a consequence of FGFR inhibition. Changes in serum phosphate levels by potassium phosphate may interfere with the determination of this initial dose increase and may cause additive hyperphosphatemia. (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.
    Ergocalciferol, Vitamin D2: (Major) High intake of phosphates concomitantly with vitamin D or vitamin D analogs may lead to hyperphosphatemia. Dose adjustment of vitamin D or vitamin D analogs may be necessary during coadministration with phosphorus salts. Additionally, serum calcium concentrations should be monitored frequently. Monitor more frequently in patients with a history of hypercalcemia.
    Fludrocortisone: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Flunisolide: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Fluticasone: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Fluticasone; Salmeterol: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Fluticasone; Umeclidinium; Vilanterol: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Fluticasone; Vilanterol: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Food: (Moderate) Food or medicines containing a high potassium content such as salt substitutes could increase the risk of complications of potassium excess when given with potassium-based phosphorous salts. (Moderate) Foods containing oxalates (found in vegetables like rhubarb, tomatoes, celery, and spinach; as well as berries, beans, nuts and chocolate) or phytates (found in bran and whole-grain cereals) may reduce the absorption of phosphorus by forming complexes with the phosphorus salt.
    Formoterol; Mometasone: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Fosinopril: (Major) Avoid coadministration of potassium phosphate and angiotensin-converting enzyme inhibitors as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Fosinopril; Hydrochlorothiazide, HCTZ: (Major) Avoid coadministration of potassium phosphate and angiotensin-converting enzyme inhibitors as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Heparin: (Moderate) Use potassium phosphates cautiously with heparin, as both drugs increase serum potassium concentrations. Concurrent use can cause hyperkalemia, especially in elderly patients or patients with impaired renal function. Patients should have serum potassium concentration determinations at periodic intervals.
    Hetastarch; Dextrose; Electrolytes: (Moderate) Phosphate may bind magnesium salts and magnesium-containing antacids (e.g., magnesium carbonate, magnesium hydroxide) may limit phosphorus absorption or phosphorus may limit magnesium absorption. If the patient requires magnesium supplements or a magnesium-containing antacid, it may be wise to separate the administration of phosphates from magnesium-containing products.
    Hydralazine: (Moderate) Use sodium phosphates cautiously with hydralazine as concurrent use can cause hypernatremia.
    Hydralazine; Hydrochlorothiazide, HCTZ: (Moderate) Use sodium phosphates cautiously with hydralazine as concurrent use can cause hypernatremia.
    Hydralazine; Isosorbide Dinitrate, ISDN: (Moderate) Use sodium phosphates cautiously with hydralazine as concurrent use can cause hypernatremia.
    Hydrochlorothiazide, HCTZ; Irbesartan: (Major) Avoid coadministration of potassium phosphate and angiotensin II receptor antagonists as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Hydrochlorothiazide, HCTZ; Lisinopril: (Major) Avoid coadministration of potassium phosphate and angiotensin-converting enzyme inhibitors as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Hydrochlorothiazide, HCTZ; Losartan: (Major) Avoid coadministration of potassium phosphate and angiotensin II receptor antagonists as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Hydrochlorothiazide, HCTZ; Methyldopa: (Moderate) Use sodium phosphates cautiously with methyldopa, as concurrent use can cause hypernatremia.
    Hydrochlorothiazide, HCTZ; Moexipril: (Major) Avoid coadministration of potassium phosphate and angiotensin-converting enzyme inhibitors as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Hydrochlorothiazide, HCTZ; Olmesartan: (Major) Avoid coadministration of potassium phosphate and angiotensin II receptor antagonists as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Hydrochlorothiazide, HCTZ; Quinapril: (Major) Avoid coadministration of potassium phosphate and angiotensin-converting enzyme inhibitors as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Hydrochlorothiazide, HCTZ; Spironolactone: (Major) Avoid coadministration of potassium phosphate and potassium-sparing diuretics as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Hydrochlorothiazide, HCTZ; Telmisartan: (Major) Avoid coadministration of potassium phosphate and angiotensin II receptor antagonists as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Hydrochlorothiazide, HCTZ; Triamterene: (Major) Avoid coadministration of potassium phosphate and potassium-sparing diuretics as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Hydrochlorothiazide, HCTZ; Valsartan: (Major) Avoid coadministration of potassium phosphate and angiotensin II receptor antagonists as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Hydrocortisone: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Irbesartan: (Major) Avoid coadministration of potassium phosphate and angiotensin II receptor antagonists as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Iron: (Moderate) It has been reported that high intakes of phosphates, such as are found in dietary supplements or food additives, can interfere with absorption of trace nutrients such as iron, copper, and zinc. The magnitude of the effect may be small, and the interactions require further study to judge clinical significance. The theorized mechanism is the formation of insoluble complexes within the gut. Until more data are available, it may be helpful to separate administration times of phosphates by as much as possible from the oral administration of iron (e.g., iron salts or polysaccharide-iron complex), copper salts, or zinc salts to limit any potential interactions.
    Lisinopril: (Major) Avoid coadministration of potassium phosphate and angiotensin-converting enzyme inhibitors as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Losartan: (Major) Avoid coadministration of potassium phosphate and angiotensin II receptor antagonists as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Magnesium Hydroxide: (Major) Aluminum hydroxide and magnesium hydroxide (as well as other antacids, i.e. aluminum hydroxide; magnesium carbonate, aluminum hydroxide; magaldrate; magnesium hydroxide, and aluminum hydroxide; magnesium trisilicate) may interact with urinary acidifiers by alkalinizing the urine. Frequent use of these high dose antacids should be avoided in patients receiving urinary acidifiers. (Moderate) Phosphate may bind magnesium salts and magnesium-containing antacids (e.g., magnesium carbonate, magnesium hydroxide) may limit phosphorus absorption or phosphorus may limit magnesium absorption. If the patient requires magnesium supplements or a magnesium-containing antacid, it may be wise to separate the administration of phosphates from magnesium-containing products.
    Magnesium Salicylate: (Moderate) Acidification of the urine may increase serum concentrations of salicylates by increasing tubular reabsorption of salicylates, however, this interaction is not likely to be clinically significant since the urine is normally acidic.
    Magnesium Salts: (Moderate) Phosphate may bind magnesium salts and magnesium-containing antacids (e.g., magnesium carbonate, magnesium hydroxide) may limit phosphorus absorption or phosphorus may limit magnesium absorption. If the patient requires magnesium supplements or a magnesium-containing antacid, it may be wise to separate the administration of phosphates from magnesium-containing products.
    Magnesium: (Moderate) Phosphate may bind magnesium salts and magnesium-containing antacids (e.g., magnesium carbonate, magnesium hydroxide) may limit phosphorus absorption or phosphorus may limit magnesium absorption. If the patient requires magnesium supplements or a magnesium-containing antacid, it may be wise to separate the administration of phosphates from magnesium-containing products.
    Methadone: (Minor) As methadone is a weak base, the renal elimination of methadone is increased by urine acidification. Thus acidifying agents may lower the serum methadone concentration. The limited amounts of circulating methadone that undergo glomerular filtration are partially reabsorbed by the kidney tubules, and this reabsorption is pH-dependent. Several studies have demonstrated that methadone is cleared faster from the body with an acidic urinary pH as compared with a more basic pH.
    Methyldopa: (Moderate) Use sodium phosphates cautiously with methyldopa, as concurrent use can cause hypernatremia.
    Methylprednisolone: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Moexipril: (Major) Avoid coadministration of potassium phosphate and angiotensin-converting enzyme inhibitors as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Mometasone: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Nebivolol; Valsartan: (Major) Avoid coadministration of potassium phosphate and angiotensin II receptor antagonists as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Olmesartan: (Major) Avoid coadministration of potassium phosphate and angiotensin II receptor antagonists as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Penicillin G: (Moderate) Use potassium phosphates cautiously with high-doses of IV potassium penicillin G, as both drugs increase serum potassium concentrations. Concurrent use can cause hyperkalemia, especially in elderly patients or patients with impaired renal function. Patients should have serum potassium concentration determinations at periodic intervals.
    Perindopril: (Major) Avoid coadministration of potassium phosphate and angiotensin-converting enzyme inhibitors as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Perindopril; Amlodipine: (Major) Avoid coadministration of potassium phosphate and angiotensin-converting enzyme inhibitors as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Potassium-sparing diuretics: (Major) Avoid coadministration of potassium phosphate and potassium-sparing diuretics as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    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.
    Quinapril: (Major) Avoid coadministration of potassium phosphate and angiotensin-converting enzyme inhibitors as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Ramipril: (Major) Avoid coadministration of potassium phosphate and angiotensin-converting enzyme inhibitors as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Sacubitril; Valsartan: (Major) Avoid coadministration of potassium phosphate and angiotensin II receptor antagonists as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Salsalate: (Moderate) Acidification of the urine may increase serum concentrations of salicylates by increasing tubular reabsorption of salicylates, however, this interaction is not likely to be clinically significant since the urine is normally acidic.
    Sevelamer: (Contraindicated) Pharmacologically, sevelamer decreases serum phosphate concentrations. Therefore, phosphate salts would be expected to counteract the pharmacological benefits of sevelamer. It would be illogical to administer phosphate or phosphorus salts to patients who require sevelamer.
    Sodium Sulfate; Magnesium Sulfate; Potassium Chloride: (Moderate) Phosphate may bind magnesium salts and magnesium-containing antacids (e.g., magnesium carbonate, magnesium hydroxide) may limit phosphorus absorption or phosphorus may limit magnesium absorption. If the patient requires magnesium supplements or a magnesium-containing antacid, it may be wise to separate the administration of phosphates from magnesium-containing products.
    Spironolactone: (Major) Avoid coadministration of potassium phosphate and potassium-sparing diuretics as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Sucralfate: (Moderate) Serum phosphorus should be checked routinely in patients treated chronically with sucralfate; sucralfate may cause hypophosphatemia and some patients may require phosphorus repletion. This nutrient interaction should be considered in patients receiving phosphates for dietary supplementation. It appears that sucralfate chelates phosphorus in the gut, forming nonabsorbable complexes. Because of sucralfate's therapeutic effect, this interaction may not be prevented by separating times of oral administration.
    Sulfamethoxazole; Trimethoprim, SMX-TMP, Cotrimoxazole: (Moderate) Use potassium phosphate cautiously with trimethoprim (especially high dose), as both drugs increase serum potassium concentrations. Concurrent use can cause hyperkalemia, especially in elderly patients or patients with impaired renal function. Patients should have serum potassium concentration determinations at periodic intervals.
    Tacrolimus: (Major) Avoid coadministration of potassium phosphate and tacrolimus as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Telmisartan: (Major) Avoid coadministration of potassium phosphate and angiotensin II receptor antagonists as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Trandolapril: (Major) Avoid coadministration of potassium phosphate and angiotensin-converting enzyme inhibitors as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Trandolapril; Verapamil: (Major) Avoid coadministration of potassium phosphate and angiotensin-converting enzyme inhibitors as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Triamcinolone: (Moderate) Use sodium phosphate cautiously with corticosteroids, especially mineralocorticoids or corticotropin, ACTH, as concurrent use can cause hypernatremia.
    Triamterene: (Major) Avoid coadministration of potassium phosphate and potassium-sparing diuretics as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Trientine: (Major) In general, oral mineral supplements should not be given since they may block the oral absorption of trientine. However, iron deficiency may develop, especially in children and menstruating or pregnant women, or as a result of the low copper diet recommended for Wilson's disease. If necessary, iron may be given in short courses, but since iron and trientine each inhibit oral absorption of the other, 2 hours should elapse between administration of trientine and iron doses.
    Trimethoprim: (Moderate) Use potassium phosphate cautiously with trimethoprim (especially high dose), as both drugs increase serum potassium concentrations. Concurrent use can cause hyperkalemia, especially in elderly patients or patients with impaired renal function. Patients should have serum potassium concentration determinations at periodic intervals.
    Valsartan: (Major) Avoid coadministration of potassium phosphate and angiotensin II receptor antagonists as concurrent use may increase the risk of severe and potentially fatal hyperkalemia, particularly in high-risk patients (renal impairment, cardiac disease, adrenal insufficiency). If concomitant use is necessary, closely monitor serum potassium concentrations.
    Vitamin D analogs: (Major) High intake of phosphates concomitantly with vitamin D analogs may lead to hyperphosphatemia. Dose adjustment of vitamin D analogs may be necessary during coadministration with phosphorus salts. Additionally, serum calcium concentrations should be monitored frequently. Monitor more frequently in patients with a history of hypercalcemia.
    Vitamin D: (Major) High intake of phosphates concomitantly with vitamin D or vitamin D analogs may lead to hyperphosphatemia. Dose adjustment of vitamin D or vitamin D analogs may be necessary during coadministration with phosphorus salts. Additionally, serum calcium concentrations should be monitored frequently. Monitor more frequently in patients with a history of hypercalcemia.
    Zinc Salts: (Minor) It has been reported that high intakes of phosphates, such as are found in dietary supplements or food additives, can interfere with absorption of trace nutrients such as iron, copper, and zinc. The magnitude of the effect may be small, and the interactions require further study to judge clinical significance. The theorized mechanism is the formation of insoluble complexes within the gut. Until more data are available, it may be helpful to separate administration times of potassium phosphate; sodium phosphateby as much as possible from the oral administration of iron (e.g., iron salts or polysaccharide-iron complex), copper salts, or zinc salts to limit any potential interactions.
    Zinc: (Minor) It has been reported that high intakes of phosphates, such as are found in dietary supplements or food additives, can interfere with absorption of trace nutrients such as iron, copper, and zinc. The magnitude of the effect may be small, and the interactions require further study to judge clinical significance. The theorized mechanism is the formation of insoluble complexes within the gut. Until more data are available, it may be helpful to separate administration times of potassium phosphate; sodium phosphateby as much as possible from the oral administration of iron (e.g., iron salts or polysaccharide-iron complex), copper salts, or zinc salts to limit any potential interactions.

    PREGNANCY AND LACTATION

    Pregnancy

    Animal reproduction studies have not been conducted with potassium phosphate; sodium phosphate. It is unknown whether phosphorus salts can cause fetal harm when administered to a pregnant woman. Potassium phosphate; sodium phosphate should only be administered during pregnancy if clearly needed. Exercise caution when considering administration to a patient with preeclampsia, as sodium-containing phosphorus salts may exacerbate toxemia of pregnancy.[57715]

    MECHANISM OF ACTION

    Phosphorus homeostasis
    Phosphorus has a number of important functions in the biochemistry of the body. The bulk of phosphorus is located in the bones, where it plays a key role in osteoblastic and osteoclastic activities. Enzymatically catalyzed phosphate-transfer reactions are numerous and vital in the metabolism of carbohydrate, lipid, and protein, and a proper concentration of the anion is of primary importance in assuring an orderly biochemical sequence. In addition, phosphorus plays an important role in modifying steady-state tissue concentrations of calcium. Phosphate ions are important buffers of the intracellular fluid, and also play a primary role in the renal excretion of hydrogen ion. In idiopathic hypercalciuria, phosphates lower urinary calcium concentrations.
     
    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.
     
    Urinary acidification
    Phosphates are excreted at the distal renal tubule where hydrogen ion is exchanged for sodium ion causing a decrease in urine pH.

    PHARMACOKINETICS

    Potassium phosphate; sodium phosphate is administered orally. In general, in adults, most absorbed phosphate is rapidly excreted into the urine.

    Oral Route

    Depending on the product, oral administration of a potassium phosphate; sodium phosphate tablet delivers approximately 250 mg of phosphorus, 134 to 298 mg of sodium (5.8 to 13 mEq), and 45 to 88 mg of potassium (1.1 to 2.3 mEq).[57715] [65784] Oral administration of a potassium phosphate; sodium phosphate packet for oral solution delivers approximately 250 mg of phosphorus, 160 mg of sodium (7 mEq), and 280 mg of potassium (7.2 mEq).[65786] In general, in adults, about two-thirds of ingested phosphate is absorbed from the bowel.[57715] [65784]