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  • CLASSES

    Calcium Supplements
    Mineral Binding Agents

    DEA CLASS

    Rx, OTC

    DESCRIPTION

    Calcium salt used as phosphate binder for the reduction of serum phosphorus in patients with chronic kidney disease (CKD)
    Guidelines recommend the serum calcium-phosphate product be maintained at less than 55 mg2/dL2 in patients with CKD
    Similar phosphorus level control as sevelamer and aluminum hydroxide

    COMMON BRAND NAMES

    Calphron, Eliphos, PhosLo, Phoslyra

    HOW SUPPLIED

    Calcium/Calcium Acetate/Calphron/Eliphos/PhosLo Oral Tab: 667mg
    Calcium/Calcium Acetate/PhosLo Oral Cap: 667mg
    Phoslyra Oral Sol: 5mL, 667mg

    DOSAGE & INDICATIONS

    For the treatment of hyperphosphatemia in patients with chronic renal failure or end stage renal disease.
    Oral dosage (tablets or capsules)
    Adults

    1334 mg (2 tablets or capsules) PO with each meal initially. The dosage may be gradually increased every 2 to 3 weeks to lower serum phosphate concentrations within the desired range as long as hypercalcemia does not develop. Most patients require 3 to 4 tablets or capsules with each meal. Generally, the maximum daily dose of elemental calcium should not exceed 2,000 mg, which is approximately 12 tablets/capsules daily; however, higher doses have been reported. Do not give other calcium supplements with calcium acetate to avoid hypercalcemia.

    Infants†, Children†, and Adolescents†

    667 to 1334 mg (1 to 2 tablets or capsules) PO three times daily with each meal. Titrate dose according to serum phosphorus concentrations. One dose titration that was used after 4 and 8 weeks after medication initiation in a clinical study is as follows: phosphorus more than 5.5 mg/dL, increase dose by 1 capsule/tablet 3 times daily; phosphorus 3.5 to 5.5 mg/dL, maintain current dose; phosphorus less than 3.5 mg/dL, decrease dose by 1 tablet/capsule 3 times daily. Usual dose based on adult patients is 3 to 4 tablets or capsules with each meal. Generally, the maximum daily dose of elemental calcium should not exceed 2,000 mg, which is approximately 12 tablets/capsules daily; however, higher doses have been reported. Do not give other calcium supplements with calcium acetate to avoid hypercalcemia. Calcium acetate has been studied in children and adolescents, ranging from 0.9 to 18 years, with chronic and end stage kidney disease. In 1 study, mean doses of approximately 54.5 mg/kg/day were reported at 3 months. Another study reported mean doses of 110 mg/kg/day (4.28 +/- 1.97 g/day) following treatment phases (approximately 18 weeks).

    Oral dosage (oral solution)
    Adults

    10 mL PO with each meal initially for dialysis patients. If hypercalcemia does not develop, increase the dose gradually every 2 to 3 weeks to lower serum phosphorus concentration to the target range. Most patients require 15 to 20 mL with each meal. Generally, the maximum daily dose of elemental calcium should not exceed 2,000 mg, which is approximately 60 mL daily; however, higher doses have been reported. Do not give other calcium supplements with calcium acetate to avoid hypercalcemia.

    Infants†, Children†, and Adolescents†

    667 to 1334 mg (5 to 10 mL) PO three times daily with each meal. Titrate dose according to serum phosphorus concentrations. One dose titration that was used after 4 and 8 weeks after medication initiation in a clinical study is as follows: phosphorus more than 5.5 mg/dL, increase dose by 667 mg (5 mL) 3 times daily; phosphorus 3.5 to 5.5 mg/dL, maintain current dose; phosphorus less than 3.5 mg/dL, decrease dose by 667 mg (5 mL) 3 times daily. Usual dose based on adult patients is 15 to 20 mL with each meal. Generally, the maximum daily dose of elemental calcium should not exceed 2,000 mg, which is approximately 60 mL daily; however, higher doses have been reported. Do not give other calcium supplements with calcium acetate to avoid hypercalcemia. Calcium acetate has been studied in children and adolescents, ranging from 0.9 to 18 years, with chronic and end stage kidney disease. In 1 study, mean doses of approximately 54.5 mg/kg/day were reported at 3 months. Another study reported mean doses of 110 mg/kg/day (4.28 +/- 1.97 g/day) following treatment phases (approximately 18 weeks).

    MAXIMUM DOSAGE

    Adults

    Specific maximum dosage information is not available; generally, the maximum daily dose of elemental calcium should not exceed 2,000 mg, which is approximately 12 tablets/capsules or 60 mL/day PO; however, higher doses have been reported.

    Geriatric

    Specific maximum dosage information is not available; generally, the maximum daily dose of elemental calcium should not exceed 2,000 mg, which is approximately 12 tablets/capsules or 60 mL/day PO; however, higher doses have been reported.

    Adolescents

    Safety and efficacy have not been established; however, calcium acetate has been used off-label in pediatric patients. Generally, the maximum daily dose of elemental calcium should not exceed 2,000 mg, which is approximately 12 tablets/capsules or 60 mL/day PO; however, higher doses have been reported.

    Children

    Safety and efficacy have not been established; however, calcium acetate has been used off-label in pediatric patients. Generally, the maximum daily dose of elemental calcium should not exceed 2,000 mg, which is approximately 12 tablets/capsules or 60 mL/day PO; however, higher doses have been reported.

    Infants

    Safety and efficacy have not been established; however, calcium acetate has been used off-label in pediatric patients. Generally, the maximum daily dose of elemental calcium should not exceed 2,000 mg, which is approximately 60 mL/day PO; however, higher doses have been reported.

    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 needed. Adjust dosage based on patient response and serum phosphorus and calcium concentrations.

    Renal Impairment

    Specific guidelines for dosage adjustments in renal impairment are not available; it appears that no dosage adjustments are needed. Adjust dosage based on patient response and serum phosphorus and calcium concentrations.

    ADMINISTRATION

    Oral Administration

    Administer with each meal.
    If a potential drug interaction is to be avoided, administer the other drug at least 1 hour before or 3 hours after the dose of calcium acetate.

    Oral Solid Formulations

    Swallow tablets and capsules whole; do not chew.

    Oral Liquid Formulations

    Always administer using a calibrated oral dosing syringe or the provided dosing cup.

    STORAGE

    Generic:
    - Store at room temperature (between 59 to 86 degrees F)
    - Store in a cool, dry place
    Calphron:
    - Store between 68 to 77 degrees F, excursions permitted 59 to 86 degrees F
    Eliphos:
    - Store at controlled room temperature (between 68 and 77 degrees F)
    PhosLo:
    - Store at controlled room temperature (between 68 and 77 degrees F)
    Phoslyra:
    - Store at 77 degrees F; excursions permitted to 59-86 degrees F

    CONTRAINDICATIONS / PRECAUTIONS

    Hypercalcemia

    Calcium acetate is contraindicated in patients with hypercalcemia. If hypercalcemia develops during calcium acetate therapy, decrease the calcium acetate dose or discontinue therapy, depending on severity of hypercalcemia. Severe hypercalcemia may require acute hemodialysis.

    Digitalis toxicity

    Calcium acetate should be used cautiously in patients with digitalis toxicity because of an increased risk of developing arrhythmias. Cardiac glycosides and calcium salts both increase intracellular calcium, so calcium acetate can worsen digitalis toxicity. Cardiac glycoside therapy, however, does not preclude the use of calcium acetate.

    Hyperparathyroidism, vitamin D toxicity

    Calcium acetate should be used cautiously, if at all, in patients with vitamin D toxicity or hyperparathyroidism. Hypercalcemia is likely to occur in either of these conditions.

    Hypercalciuria, nephrolithiasis

    Calcium acetate should be used with caution in patients with preexisting hypercalciuria or nephrolithiasis, especially if renal calculi are present.

    Sarcoidosis

    Calcium acetate should be used with caution in patients with sarcoidosis as hypercalcemia is more likely to occur in these patients.

    Pregnancy

    There are no adequate, well-controlled studies of calcium acetate use in human pregnancy and animal reproduction studies have not been performed. Patients with end-stage renal disease may develop hypercalcemia with calcium acetate treatment. Maintenance of normal serum calcium concentrations is important for maternal and fetal well being. Hypercalcemia during pregnancy may increase the risk of maternal and neonatal complications, such as stillbirth, preterm delivery, and neonatal hypercalcemia and hypoparathyroidism. Calcium acetate treatment as recommended is not expected to cause fetal harm as long as maternal calcium concentrations are properly monitored and maintained during and following treatment.

    Breast-feeding

    Calcium acetate is excreted in human milk; however, breast-feeding by a woman receiving calcium acetate is not expected to cause infant harm, provided maternal serum calcium concentrations are appropriately monitored and maintained within the normal range.

    ADVERSE REACTIONS

    Severe

    coma / Early / Incidence not known
    milk-alkali syndrome / Delayed / Incidence not known

    Moderate

    hypercalcemia / Delayed / 7.0-16.0
    constipation / Delayed / Incidence not known
    hypertension / Early / Incidence not known
    delirium / Early / Incidence not known
    confusion / Early / Incidence not known
    premature ventricular contractions (PVCs) / Early / Incidence not known
    edema / Delayed / Incidence not known
    nephrolithiasis / Delayed / Incidence not known

    Mild

    nausea / Early / 3.0-6.0
    vomiting / Early / 2.0-4.0
    drowsiness / Early / Incidence not known
    polyuria / Early / Incidence not known
    anorexia / Delayed / Incidence not known
    diarrhea / Early / Incidence not known
    pruritus / Rapid / Incidence not known
    asthenia / Delayed / Incidence not known
    weakness / Early / Incidence not known
    dizziness / Early / Incidence not known
    muscle cramps / Delayed / Incidence not known

    DRUG INTERACTIONS

    Abacavir; Dolutegravir; Lamivudine: (Moderate) Administer dolutegravir 2 hours before or 6 hours after taking supplements containing calcium if given under fasting conditions. When taken with food, dolutegravir and supplements containing calcium can be taken at the same time. Simultaneous administration under fasted conditions may result in reduced bioavailability of dolutegravir.
    Alendronate: (Moderate) Separate administration of alendronate and calcium-containing supplements by at least 30 minutes. Calcium will interfere with the absorption of alendronate.
    Alendronate; Cholecalciferol: (Moderate) Separate administration of alendronate and calcium-containing supplements by at least 30 minutes. Calcium will interfere with the absorption of alendronate.
    Aliskiren; Amlodipine; Hydrochlorothiazide, HCTZ: (Moderate) Monitor serum calcium concentration during concomitant calcium and thiazide diuretic use due to the risk for hypercalcemia. Thiazide diuretics may decrease urinary calcium excretion and cause intermittent and slight increases in serum calcium.
    Aliskiren; Hydrochlorothiazide, HCTZ: (Moderate) Monitor serum calcium concentration during concomitant calcium and thiazide diuretic use due to the risk for hypercalcemia. Thiazide diuretics may decrease urinary calcium excretion and cause intermittent and slight increases in serum calcium.
    Amiloride; Hydrochlorothiazide, HCTZ: (Moderate) Monitor serum calcium concentration during concomitant calcium and thiazide diuretic use due to the risk for hypercalcemia. Thiazide diuretics may decrease urinary calcium excretion and cause intermittent and slight increases in serum calcium.
    Amlodipine; Valsartan; Hydrochlorothiazide, HCTZ: (Moderate) Monitor serum calcium concentration during concomitant calcium and thiazide diuretic use due to the risk for hypercalcemia. Thiazide diuretics may decrease urinary calcium excretion and cause intermittent and slight increases in serum calcium.
    Atenolol: (Minor) Calcium antacids (e.g., calcium carbonate) and supplements (e.g., other oral calcium salts) have been reported to reduce the mean peak concentrations by 51% and the AUC of atenolol by 32%. In another study, antacids reduced the AUC of atenolol by 33%. Separate doses of atenolol and calcium-containing antacids or supplements by at least 2 hours to minimize this potential interaction,. However, most clinicians consider the interaction of atenolol with antacids to be of minor clinical significance, since clinical efficacy (heart rate and blood pressure parameters) appear to be unchanged under usual intermittent clinical use.
    Atenolol; Chlorthalidone: (Moderate) Monitor serum calcium concentration during concomitant calcium and thiazide diuretic use due to the risk for hypercalcemia. Thiazide diuretics may decrease urinary calcium excretion and cause intermittent and slight increases in serum calcium. (Minor) Calcium antacids (e.g., calcium carbonate) and supplements (e.g., other oral calcium salts) have been reported to reduce the mean peak concentrations by 51% and the AUC of atenolol by 32%. In another study, antacids reduced the AUC of atenolol by 33%. Separate doses of atenolol and calcium-containing antacids or supplements by at least 2 hours to minimize this potential interaction,. However, most clinicians consider the interaction of atenolol with antacids to be of minor clinical significance, since clinical efficacy (heart rate and blood pressure parameters) appear to be unchanged under usual intermittent clinical use.
    Azilsartan; Chlorthalidone: (Moderate) Monitor serum calcium concentration during concomitant calcium and thiazide diuretic use due to the risk for hypercalcemia. Thiazide diuretics may decrease urinary calcium excretion and cause intermittent and slight increases in serum calcium.
    Baloxavir Marboxil: (Major) Do not administer baloxavir with products that contain calcium. Polyvalent cations, such as calcium, can chelate with baloxavir, reducing its absorption.
    Benazepril; Hydrochlorothiazide, HCTZ: (Moderate) Monitor serum calcium concentration during concomitant calcium and thiazide diuretic use due to the risk for hypercalcemia. Thiazide diuretics may decrease urinary calcium excretion and cause intermittent and slight increases in serum calcium.
    Bendroflumethiazide; Nadolol: (Moderate) Monitor serum calcium concentration during concomitant calcium and thiazide diuretic use due to the risk for hypercalcemia. Thiazide diuretics may decrease urinary calcium excretion and cause intermittent and slight increases in serum calcium.
    Bictegravir; Emtricitabine; Tenofovir Alafenamide: (Moderate) Administer bictegravir with food at the same time as oral calcium supplements. Routine administration of bictegravir under fasting conditions simultaneously with, or 2 hours after, calcium supplements is not recommended. Calcium is a polyvalent cation that can bind bictegravir in the GI tract. Taking these drugs simultaneously without food results in reduced bioavailability of bictegravir. In drug interaction studies, simultaneous administration of bictegravir with another calcium supplement under fasted conditions decreased the mean AUC of bictegravir by approximately 33%.
    Bisoprolol; Hydrochlorothiazide, HCTZ: (Moderate) Monitor serum calcium concentration during concomitant calcium and thiazide diuretic use due to the risk for hypercalcemia. Thiazide diuretics may decrease urinary calcium excretion and cause intermittent and slight increases in serum calcium.
    Cabotegravir: (Moderate) Administer oral calcium at least two hours before or four hours after taking oral cabotegravir. Calcium is a polyvalent cation that can bind cabotegravir in the GI tract. Taking these drugs simultaneously may result in reduced oral bioavailability of cabotegravir.
    Cabotegravir; Rilpivirine: (Moderate) Administer oral calcium at least two hours before or four hours after taking oral cabotegravir. Calcium is a polyvalent cation that can bind cabotegravir in the GI tract. Taking these drugs simultaneously may result in reduced oral bioavailability of cabotegravir.
    Calcipotriene: (Minor) There is evidence that calcipotriene can be absorbed in amounts that are sufficient to produce systemic effects, including elevated serum calcium; hypercalcemia has been observed in normal prescription use. Use calcipotriene cautiously with other agents that can produce hypercalcemia (e.g., calcium salts or supplements including calcium carbonate).
    Calcipotriene; Betamethasone: (Minor) There is evidence that calcipotriene can be absorbed in amounts that are sufficient to produce systemic effects, including elevated serum calcium; hypercalcemia has been observed in normal prescription use. Use calcipotriene cautiously with other agents that can produce hypercalcemia (e.g., calcium salts or supplements including calcium carbonate).
    Calcitonin: (Moderate) Calcitonin is given to hypercalcemic patients to reduce serum calcium concentrations. For the treatment of hypercalcemia, calcium supplements should be avoided. Calcium salts, including calcium carbonate, can elevate serum calcium concentrations and antagonize the effects of the calcitonin for this condition. For the treatment of osteoporosis adequate intake of calcium salts are necessary in conjunction with calcitonin. An increase in serum calcium concentrations helps to reduce bone resorption and loss of bone mass, and offsets the effect of calcitonin in lowering serum calcium levels.
    Calcium Carbonate; Risedronate: (Moderate) Separate administration of oral risedronate and calcium-containing supplements by at least 2 hours. Calcium will interfere with the absorption of oral risedronate.
    Calcium Phosphate, Supersaturated: (Moderate) The concomitant use of oral sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous preparations in conjunction with antacids containing calcium (e.g., calcium carbonate, calcium salts) may bind the phosphate in the stomach and reduce its absorption. If the patient requires multiple mineral supplements or concurrent use of antacids, it is prudent to separate the administration of sodium phosphate salts from calcium containing products by at least one hour.
    Candesartan; Hydrochlorothiazide, HCTZ: (Moderate) Monitor serum calcium concentration during concomitant calcium and thiazide diuretic use due to the risk for hypercalcemia. Thiazide diuretics may decrease urinary calcium excretion and cause intermittent and slight increases in serum calcium.
    Captopril; Hydrochlorothiazide, HCTZ: (Moderate) Monitor serum calcium concentration during concomitant calcium and thiazide diuretic use due to the risk for hypercalcemia. Thiazide diuretics may decrease urinary calcium excretion and cause intermittent and slight increases in serum calcium.
    Cardiac glycosides: (Moderate) Monitor for signs and symptoms of digoxin toxicity during concomitant calcium use. Sporadic case reports have suggested that hypercalcemia may predispose persons to digoxin toxicity. If calcium is administered intravenously rapidly in a person receiving digoxin, serious arrhythmias may occur.
    Ceftriaxone: (Major) Ceftriaxone is contraindicated in neonates who are receiving or are expected to receive IV calcium-containing solutions, including calcium-containing parenteral nutrition. Cases of fatal pulmonary and renal precipitate embolism in neonates have been described. There have been no reports of an interaction between ceftriaxone and oral calcium-containing products or between intramuscular ceftriaxone and calcium-containing products. Precipitation of ceftriaxone and calcium can occur when mixed. In patients other than neonates, the risk for precipitate embolism may be adequately addressed by separating administrations or administering each medication sequentially if IV infusion lines are thoroughly flushed between infusions with a compatible fluid.
    Chlorothiazide: (Moderate) Monitor serum calcium concentration during concomitant calcium and thiazide diuretic use due to the risk for hypercalcemia. Thiazide diuretics may decrease urinary calcium excretion and cause intermittent and slight increases in serum calcium.
    Chlorthalidone: (Moderate) Monitor serum calcium concentration during concomitant calcium and thiazide diuretic use due to the risk for hypercalcemia. Thiazide diuretics may decrease urinary calcium excretion and cause intermittent and slight increases in serum calcium.
    Chlorthalidone; Clonidine: (Moderate) Monitor serum calcium concentration during concomitant calcium and thiazide diuretic use due to the risk for hypercalcemia. Thiazide diuretics may decrease urinary calcium excretion and cause intermittent and slight increases in serum calcium.
    Ciprofloxacin: (Moderate) Administer oral ciprofloxacin at least 2 hours before or 6 hours after oral products that contain calcium. Ciprofloxacin absorption may be reduced as quinolone antibiotics can chelate with divalent or trivalent cations. Examples of compounds that may interfere with quinolone bioavailability include antacids and multivitamins that contain calcium.
    Conjugated Estrogens: (Minor) Estrogens can increase calcium absorption. Use caution in patients predisposed to hypercalcemia or nephrolithiasis.
    Conjugated Estrogens; Bazedoxifene: (Minor) Estrogens can increase calcium absorption. Use caution in patients predisposed to hypercalcemia or nephrolithiasis.
    Conjugated Estrogens; Medroxyprogesterone: (Minor) Estrogens can increase calcium absorption. Use caution in patients predisposed to hypercalcemia or nephrolithiasis.
    Delafloxacin: (Major) Administer oral delafloxacin at least 2 hours before or 6 hours after oral products that contain calcium. Delafloxacin absorption may be reduced as quinolone antibiotics can chelate with divalent or trivalent cations. Examples of compounds that may interfere with fluoroquinolone bioavailability include antacids and multivitamins that contain calcium.
    Desogestrel; Ethinyl Estradiol: (Minor) Estrogens can increase calcium absorption. Use caution in patients predisposed to hypercalcemia or nephrolithiasis.
    Dienogest; Estradiol valerate: (Minor) Estrogens can increase calcium absorption. Use caution in patients predisposed to hypercalcemia or nephrolithiasis.
    Diethylstilbestrol, DES: (Minor) Estrogens can increase calcium absorption. Use caution in patients predisposed to hypercalcemia or nephrolithiasis.
    Dolutegravir: (Moderate) Administer dolutegravir 2 hours before or 6 hours after taking supplements containing calcium if given under fasting conditions. When taken with food, dolutegravir and supplements containing calcium can be taken at the same time. Simultaneous administration under fasted conditions may result in reduced bioavailability of dolutegravir.
    Dolutegravir; Lamivudine: (Moderate) Administer dolutegravir 2 hours before or 6 hours after taking supplements containing calcium if given under fasting conditions. When taken with food, dolutegravir and supplements containing calcium can be taken at the same time. Simultaneous administration under fasted conditions may result in reduced bioavailability of dolutegravir.
    Dolutegravir; Rilpivirine: (Moderate) Administer dolutegravir 2 hours before or 6 hours after taking supplements containing calcium if given under fasting conditions. When taken with food, dolutegravir and supplements containing calcium can be taken at the same time. Simultaneous administration under fasted conditions may result in reduced bioavailability of dolutegravir.
    Drospirenone; Estetrol: (Minor) Estrogens can increase calcium absorption. Use caution in patients predisposed to hypercalcemia or nephrolithiasis.
    Drospirenone; Estradiol: (Minor) Estrogens can increase calcium absorption. Use caution in patients predisposed to hypercalcemia or nephrolithiasis.
    Drospirenone; Ethinyl Estradiol: (Minor) Estrogens can increase calcium absorption. Use caution in patients predisposed to hypercalcemia or nephrolithiasis.
    Drospirenone; Ethinyl Estradiol; Levomefolate: (Minor) Estrogens can increase calcium absorption. Use caution in patients predisposed to hypercalcemia or nephrolithiasis.
    Edetate Calcium Disodium, Calcium EDTA: (Major) Because edetate disodium chelates and lowers serum calcium, oral or parenteral calcium salts should not be administered concomitantly.
    Edetate Disodium, Disodium EDTA: (Major) Because edetate disodium chelates and lowers serum calcium, oral or parenteral calcium salts should not be administered concomitantly.
    Elagolix; Estradiol; Norethindrone acetate: (Minor) Estrogens can increase calcium absorption. Use caution in patients predisposed to hypercalcemia or nephrolithiasis.
    Eltrombopag: (Major) Eltrombopag chelates polyvalent cations (e.g., calcium, aluminum, and magnesium) in food, mineral supplements, and antacids. In a clinical study, systemic exposure to eltrombopag was decreased by 70% when it was administered with a polyvalent cation-containing antacid. Administer eltrombopag at least 2 hours before or 4 hours after any oral products containing polyvalent cations, such as aluminum salts, (like aluminum hydroxide), calcium salts, (including calcium carbonate), and magnesium salts.
    Elvitegravir: (Moderate) Separate administration of elvitegravir and calcium by at least 2 hours. Due to the formation of ionic complexes in the gastrointestinal tract, simultaneous administration results in lower elvitegravir plasma concentrations.
    Elvitegravir; Cobicistat; Emtricitabine; Tenofovir Alafenamide: (Moderate) Separate administration of elvitegravir and calcium by at least 2 hours. Due to the formation of ionic complexes in the gastrointestinal tract, simultaneous administration results in lower elvitegravir plasma concentrations.
    Elvitegravir; Cobicistat; Emtricitabine; Tenofovir Disoproxil Fumarate: (Moderate) Separate administration of elvitegravir and calcium by at least 2 hours. Due to the formation of ionic complexes in the gastrointestinal tract, simultaneous administration results in lower elvitegravir plasma concentrations.
    Enalapril; Hydrochlorothiazide, HCTZ: (Moderate) Monitor serum calcium concentration during concomitant calcium and thiazide diuretic use due to the risk for hypercalcemia. Thiazide diuretics may decrease urinary calcium excretion and cause intermittent and slight increases in serum calcium.
    Eprosartan; Hydrochlorothiazide, HCTZ: (Moderate) Monitor serum calcium concentration during concomitant calcium and thiazide diuretic use due to the risk for hypercalcemia. Thiazide diuretics may decrease urinary calcium excretion and cause intermittent and slight increases in serum calcium.
    Erdafitinib: (Major) Avoid coadministration of calcium acetate with erdafitinib before the initial dose increase period (days 14 to 21) which is based on serum phosphate levels. Calcium acetate decreases serum phosphate levels. The initial dose increase of erdafitinib on days 14 to 21 is based on serum phosphate levels; changes in serum phosphate levels by calcium acetate may interfere with the determination of this initial dose increase.
    Esterified Estrogens: (Minor) Estrogens can increase calcium absorption. Use caution in patients predisposed to hypercalcemia or nephrolithiasis.
    Esterified Estrogens; Methyltestosterone: (Minor) Estrogens can increase calcium absorption. Use caution in patients predisposed to hypercalcemia or nephrolithiasis.
    Estradiol Cypionate; Medroxyprogesterone: (Minor) Estrogens can increase calcium absorption. Use caution in patients predisposed to hypercalcemia or nephrolithiasis.
    Estradiol: (Minor) Estrogens can increase calcium absorption. Use caution in patients predisposed to hypercalcemia or nephrolithiasis.
    Estradiol; Levonorgestrel: (Minor) Estrogens can increase calcium absorption. Use caution in patients predisposed to hypercalcemia or nephrolithiasis.
    Estradiol; Norethindrone: (Minor) Estrogens can increase calcium absorption. Use caution in patients predisposed to hypercalcemia or nephrolithiasis.
    Estradiol; Norgestimate: (Minor) Estrogens can increase calcium absorption. Use caution in patients predisposed to hypercalcemia or nephrolithiasis.
    Estradiol; Progesterone: (Minor) Estrogens can increase calcium absorption. Use caution in patients predisposed to hypercalcemia or nephrolithiasis.
    Estramustine: (Major) Administration of estramustine with calcium impairs the oral absorption of estramustine significantly, due to formation of a calcium-phosphate complex. Calcium-containing drugs must not be taken simultaneously with estramustine. Patients should be instructed to take estramustine with water at least 1 hour before or 2 hours after calcium supplements.
    Estrogens: (Minor) Estrogens can increase calcium absorption. Use caution in patients predisposed to hypercalcemia or nephrolithiasis.
    Estropipate: (Minor) Estrogens can increase calcium absorption. Use caution in patients predisposed to hypercalcemia or nephrolithiasis.
    Ethinyl Estradiol: (Minor) Estrogens can increase calcium absorption. Use caution in patients predisposed to hypercalcemia or nephrolithiasis.
    Ethinyl Estradiol; Levonorgestrel; Folic Acid; Levomefolate: (Minor) Estrogens can increase calcium absorption. Use caution in patients predisposed to hypercalcemia or nephrolithiasis.
    Ethinyl Estradiol; Norelgestromin: (Minor) Estrogens can increase calcium absorption. Use caution in patients predisposed to hypercalcemia or nephrolithiasis.
    Ethinyl Estradiol; Norethindrone Acetate: (Minor) Estrogens can increase calcium absorption. Use caution in patients predisposed to hypercalcemia or nephrolithiasis.
    Ethinyl Estradiol; Norgestrel: (Minor) Estrogens can increase calcium absorption. Use caution in patients predisposed to hypercalcemia or nephrolithiasis.
    Ethotoin: (Major) Oral absorption of phenytoin can be reduced by calcium salts. Calcium salts can form complexes that are nonabsorbable. Separating the administration of phenytoin and calcium salts by at least 2 hours to help avoid this interaction. A similar interaction may occur with ethotoin.
    Ethynodiol Diacetate; Ethinyl Estradiol: (Minor) Estrogens can increase calcium absorption. Use caution in patients predisposed to hypercalcemia or nephrolithiasis.
    Etidronate: (Moderate) Separate administration of oral etidronate and calcium-containing supplements by at least 2 hours. Calcium will interfere with the absorption of oral etidronate.
    Etonogestrel; Ethinyl Estradiol: (Minor) Estrogens can increase calcium absorption. Use caution in patients predisposed to hypercalcemia or nephrolithiasis.
    Fosinopril; Hydrochlorothiazide, HCTZ: (Moderate) Monitor serum calcium concentration during concomitant calcium and thiazide diuretic use due to the risk for hypercalcemia. Thiazide diuretics may decrease urinary calcium excretion and cause intermittent and slight increases in serum calcium.
    Hydralazine; Hydrochlorothiazide, HCTZ: (Moderate) Monitor serum calcium concentration during concomitant calcium and thiazide diuretic use due to the risk for hypercalcemia. Thiazide diuretics may decrease urinary calcium excretion and cause intermittent and slight increases in serum calcium.
    Hydrochlorothiazide, HCTZ: (Moderate) Monitor serum calcium concentration during concomitant calcium and thiazide diuretic use due to the risk for hypercalcemia. Thiazide diuretics may decrease urinary calcium excretion and cause intermittent and slight increases in serum calcium.
    Hydrochlorothiazide, HCTZ; Methyldopa: (Moderate) Monitor serum calcium concentration during concomitant calcium and thiazide diuretic use due to the risk for hypercalcemia. Thiazide diuretics may decrease urinary calcium excretion and cause intermittent and slight increases in serum calcium.
    Hydrochlorothiazide, HCTZ; Moexipril: (Moderate) Monitor serum calcium concentration during concomitant calcium and thiazide diuretic use due to the risk for hypercalcemia. Thiazide diuretics may decrease urinary calcium excretion and cause intermittent and slight increases in serum calcium.
    Ibandronate: (Moderate) Separate administration of oral ibandronate and calcium-containing supplements by at least 1 hour. Calcium will interfere with the absorption of oral ibandronate.
    Ibritumomab Tiuxetan: (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.
    Irbesartan; Hydrochlorothiazide, HCTZ: (Moderate) Monitor serum calcium concentration during concomitant calcium and thiazide diuretic use due to the risk for hypercalcemia. Thiazide diuretics may decrease urinary calcium excretion and cause intermittent and slight increases in serum calcium.
    Levofloxacin: (Moderate) Administer oral products that contain calcium at least 2 hours before or 2 hours after orally administered levofloxacin. Levofloxacin absorption may be reduced as quinolone antibiotics can chelate with divalent or trivalent cations. Chelation of divalent cations with levofloxacin is less than with other quinolones. Examples of compounds that may interfere with quinolone bioavailability include antacids and multivitamins that contain calcium.
    Levonorgestrel; Ethinyl Estradiol: (Minor) Estrogens can increase calcium absorption. Use caution in patients predisposed to hypercalcemia or nephrolithiasis.
    Levonorgestrel; Ethinyl Estradiol; Ferrous Bisglycinate: (Minor) Estrogens can increase calcium absorption. Use caution in patients predisposed to hypercalcemia or nephrolithiasis.
    Lisinopril; Hydrochlorothiazide, HCTZ: (Moderate) Monitor serum calcium concentration during concomitant calcium and thiazide diuretic use due to the risk for hypercalcemia. Thiazide diuretics may decrease urinary calcium excretion and cause intermittent and slight increases in serum calcium.
    Losartan; Hydrochlorothiazide, HCTZ: (Moderate) Monitor serum calcium concentration during concomitant calcium and thiazide diuretic use due to the risk for hypercalcemia. Thiazide diuretics may decrease urinary calcium excretion and cause intermittent and slight increases in serum calcium.
    Mestranol; Norethindrone: (Minor) Estrogens can increase calcium absorption. Use caution in patients predisposed to hypercalcemia or nephrolithiasis.
    Methyclothiazide: (Moderate) Monitor serum calcium concentration during concomitant calcium and thiazide diuretic use due to the risk for hypercalcemia. Thiazide diuretics may decrease urinary calcium excretion and cause intermittent and slight increases in serum calcium.
    Metolazone: (Moderate) Monitor serum calcium concentration during concomitant calcium and thiazide diuretic use due to the risk for hypercalcemia. Thiazide diuretics may decrease urinary calcium excretion and cause intermittent and slight increases in serum calcium.
    Metoprolol; Hydrochlorothiazide, HCTZ: (Moderate) Monitor serum calcium concentration during concomitant calcium and thiazide diuretic use due to the risk for hypercalcemia. Thiazide diuretics may decrease urinary calcium excretion and cause intermittent and slight increases in serum calcium.
    Moxifloxacin: (Major) Administer oral moxifloxacin at least 4 hours before or 8 hours after oral products that contain calcium. Moxifloxacin absorption may be reduced as quinolone antibiotics can chelate with divalent or trivalent cations. Examples of compounds that may interfere with quinolone bioavailability include antacids and multivitamins that contain calcium.
    Neuromuscular blockers: (Moderate) Concomitant use of neuromuscular blockers and calcium may result in resistance to neuromuscular blockade. Calcium antagonizes the potentiating effect of magnesium on neuromuscular blockade. Also, calcium triggers acetylcholine release, and therefore, may both reduce the sensitivity to neuromuscular blockers and decrease the duration of neuromuscular blockade.
    Norethindrone Acetate; Ethinyl Estradiol; Ferrous fumarate: (Minor) Estrogens can increase calcium absorption. Use caution in patients predisposed to hypercalcemia or nephrolithiasis.
    Norethindrone; Ethinyl Estradiol: (Minor) Estrogens can increase calcium absorption. Use caution in patients predisposed to hypercalcemia or nephrolithiasis.
    Norethindrone; Ethinyl Estradiol; Ferrous fumarate: (Minor) Estrogens can increase calcium absorption. Use caution in patients predisposed to hypercalcemia or nephrolithiasis.
    Norgestimate; Ethinyl Estradiol: (Minor) Estrogens can increase calcium absorption. Use caution in patients predisposed to hypercalcemia or nephrolithiasis.
    Ofloxacin: (Moderate) Administer oral products that contain calcium at least 2 hours before or 2 hours after ofloxacin. Ofloxacin absorption may be reduced as quinolone antibiotics can chelate with divalent or trivalent cations. Examples of compounds that may interfere with quinolone bioavailability include antacids and multivitamins that contain calcium.
    Olmesartan; Amlodipine; Hydrochlorothiazide, HCTZ: (Moderate) Monitor serum calcium concentration during concomitant calcium and thiazide diuretic use due to the risk for hypercalcemia. Thiazide diuretics may decrease urinary calcium excretion and cause intermittent and slight increases in serum calcium.
    Olmesartan; Hydrochlorothiazide, HCTZ: (Moderate) Monitor serum calcium concentration during concomitant calcium and thiazide diuretic use due to the risk for hypercalcemia. Thiazide diuretics may decrease urinary calcium excretion and cause intermittent and slight increases in serum calcium.
    Phenytoin: (Moderate) Oral absorption of phenytoin can be reduced by calcium salts. Calcium salts can form complexes that are nonabsorbable. Separating the administration of phenytoin and calcium salts by at least 2 hours will help avoid this interaction. A similar interaction may occur with ethotoin.
    Phosphorated Carbohydrate Solution: (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.
    Phosphorus: (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.
    Potassium Phosphate: (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.
    Potassium Phosphate; Sodium Phosphate: (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.
    Propranolol; Hydrochlorothiazide, HCTZ: (Moderate) Monitor serum calcium concentration during concomitant calcium and thiazide diuretic use due to the risk for hypercalcemia. Thiazide diuretics may decrease urinary calcium excretion and cause intermittent and slight increases in serum calcium.
    Quinapril; Hydrochlorothiazide, HCTZ: (Moderate) Monitor serum calcium concentration during concomitant calcium and thiazide diuretic use due to the risk for hypercalcemia. Thiazide diuretics may decrease urinary calcium excretion and cause intermittent and slight increases in serum calcium.
    Relugolix; Estradiol; Norethindrone acetate: (Minor) Estrogens can increase calcium absorption. Use caution in patients predisposed to hypercalcemia or nephrolithiasis.
    Risedronate: (Moderate) Separate administration of oral risedronate and calcium-containing supplements by at least 2 hours. Calcium will interfere with the absorption of oral risedronate.
    Segesterone Acetate; Ethinyl Estradiol: (Minor) Estrogens can increase calcium absorption. Use caution in patients predisposed to hypercalcemia or nephrolithiasis.
    Sodium Fluoride: (Moderate) Absorption of sodium fluoride may be reduced by concomitant use of antacids that contain magnesium, aluminum, or calcium. An interval of at least 2 hours is advisable between administration of sodium fluoride and antacids.
    Sodium Phosphate Monobasic Monohydrate; Sodium Phosphate Dibasic Anhydrous: (Moderate) The concomitant use of oral sodium phosphate monobasic monohydrate; sodium phosphate dibasic anhydrous preparations in conjunction with antacids containing calcium (e.g., calcium carbonate, calcium salts) may bind the phosphate in the stomach and reduce its absorption. If the patient requires multiple mineral supplements or concurrent use of antacids, it is prudent to separate the administration of sodium phosphate salts from calcium containing products by at least one hour.
    Spironolactone; Hydrochlorothiazide, HCTZ: (Moderate) Monitor serum calcium concentration during concomitant calcium and thiazide diuretic use due to the risk for hypercalcemia. Thiazide diuretics may decrease urinary calcium excretion and cause intermittent and slight increases in serum calcium.
    Sucralfate: (Moderate) Oral antacids, including calcium salts, potentially interfere with gastric mucosal binding of sucralfate. This interaction can be minimized by staggering the doses of these agents as much as possible.
    Telmisartan; Hydrochlorothiazide, HCTZ: (Moderate) Monitor serum calcium concentration during concomitant calcium and thiazide diuretic use due to the risk for hypercalcemia. Thiazide diuretics may decrease urinary calcium excretion and cause intermittent and slight increases in serum calcium.
    Tetracyclines: (Moderate) Divalent or trivalent cations readily chelate with tetracycline antibiotics, forming insoluble compounds. The oral absorption of these antibiotics will be significantly reduced by other orally administered compounds that contain calcium salts, particularly if the time of administration is within 60 minutes of each other. Calcium salts and tetracyclines should not be administered within 1 to 2 hours of each other, although doxycycline chelates less with calcium than other tetracyclines.
    Thiazide diuretics: (Moderate) Monitor serum calcium concentration during concomitant calcium and thiazide diuretic use due to the risk for hypercalcemia. Thiazide diuretics may decrease urinary calcium excretion and cause intermittent and slight increases in serum calcium.
    Thyroid hormones: (Moderate) Thyroid hormones should be administered at least 4 hours before or after the ingestion of oral calcium supplements. Calcium salts have been reported to chelate oral thyroid hormones within the GI tract when administered simultaneously, leading to decreased thyroid hormone absorption. Some case reports have described clinical hypothyroidism resulting from coadministration of thyroid hormones with oral calcium supplements.
    Triamterene; Hydrochlorothiazide, HCTZ: (Moderate) Monitor serum calcium concentration during concomitant calcium and thiazide diuretic use due to the risk for hypercalcemia. Thiazide diuretics may decrease urinary calcium excretion and cause intermittent and slight increases in serum calcium.
    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.
    Valsartan; Hydrochlorothiazide, HCTZ: (Moderate) Monitor serum calcium concentration during concomitant calcium and thiazide diuretic use due to the risk for hypercalcemia. Thiazide diuretics may decrease urinary calcium excretion and cause intermittent and slight increases in serum calcium.
    Vitamin A: (Minor) Doses in excess of 1,500 to 2,000 mcg per day of Vitamin A may lead to bone loss and will counteract the effects of supplementation with calcium salts.
    Vitamin D analogs: (Moderate) Monitor serum calcium concentrations during concomitant use of high doses of calcium and vitamin D analogs; a dosage adjustment of the vitamin D analog may be needed. Hypercalcemia may be exacerbated by concomitant administration.

    PREGNANCY AND LACTATION

    Pregnancy

    There are no adequate, well-controlled studies of calcium acetate use in human pregnancy and animal reproduction studies have not been performed. Patients with end-stage renal disease may develop hypercalcemia with calcium acetate treatment. Maintenance of normal serum calcium concentrations is important for maternal and fetal well being. Hypercalcemia during pregnancy may increase the risk of maternal and neonatal complications, such as stillbirth, preterm delivery, and neonatal hypercalcemia and hypoparathyroidism. Calcium acetate treatment as recommended is not expected to cause fetal harm as long as maternal calcium concentrations are properly monitored and maintained during and following treatment.

    Calcium acetate is excreted in human milk; however, breast-feeding by a woman receiving calcium acetate is not expected to cause infant harm, provided maternal serum calcium concentrations are appropriately monitored and maintained within the normal range.

    MECHANISM OF ACTION

    Calcium acetate when taken with meals, combines with dietary phosphate to form an insoluble calcium phosphate complex, which is excreted in the feces, resulting in decreased phosphorus concentrations.

    PHARMACOKINETICS

    Calcium acetate is administered orally. Approximately 1.04 mg of phosphate is bound per mg of calcium absorbed when given with meals and 1 mg of phosphate is bound per 2.9 mg of calcium absorbed when given between meals. Approximately 45 mg of phosphate is bound per 1 gram of calcium acetate. Calcium is primarily excreted in the feces and bile (80%). Urinary excretion accounts for the remainder (20%). However, approximately 99% of filtered calcium is reabsorbed by the kidney with less than 1% excreted. Parathyroid hormone, calcitonin, and 1,25 dihydroxycholecalciferol are primarily responsible for controlling calcium equilibrium. Insulin, thyroxine, growth hormone, androgens, estrogens, adrenal corticosteroids, and inorganic phosphate also contribute.
     
    Affected cytochrome P450 isoenzymes: none

    Oral Route

    Calcium acetate absorption is approximately 40% and 30% under fasting and non-fasting conditions, respectively. Similar changes in serum calcium and phosphorus concentrations have been observed with calcium acetate, whether given as the oral solution, tablets, or gelcaps.