magnesium citrate (OTC)

Brand and Other Names:
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Dosing & Uses

AdultPediatric

Dosage Forms & Strengths

liquid

  • 290mg/5mL

tablet

  • 100mg (elemental)

Nutritional Supplementation

19-30 years: Men, 400 mg/day; women, 310 mg/day; pregnant women (≤50 years), 350 mg/day; breastfeeding women (≤50 years), 310 mg/day

>30 years: Men, 420 mg/day; women, 320 mg/day; pregnant women (≤50 years), 360 mg/day; breastfeeding women (≤50 years), 320 mg/day

Constipation/Laxative

195-300 mL PO in single daily dose or in divided doses with full glass of water

Alternative: 2-4 tablets PO at bedtime

Acid Indigestion

1 tablet twice daily or as directed by healthcare provider

Dosing Considerations

Should be refrigerated to maintain potency and palatability

Dosage Forms & Strengths

liquid

  • 290mg/5mL

tablet

  • 100mg (elemental)

Constipation/Laxative

<2 years: Safety and efficacy not established

2-6 years: 60-90 mL PO once or divided doses; not to exceed 90 mL/24hr

6-12 years: 90-210 mL in single dose or in divided doses with full glass of water

>12 years: 195-300 mL PO in single daily dose or in divided doses with full glass of water; alternatively, may administer 2-4 tablets PO at bedtime

Dosing Considerations

Should be refrigerated to maintain potency and palatability

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Interactions

Interaction Checker

and magnesium citrate

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      Serious - Use Alternative

        Significant - Monitor Closely

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            Contraindicated (0)

              Serious - Use Alternative (9)

              • baloxavir marboxil

                magnesium citrate will decrease the level or effect of baloxavir marboxil by cation binding in GI tract. Avoid or Use Alternate Drug. Baloxavir may bind to polyvalent cations resulting in decreased absorption. Studies in monkeys showed concurrent use with calcium, aluminum, or iron caused significantly decreased plasma levels. Human studies not conducted.

              • demeclocycline

                magnesium citrate decreases levels of demeclocycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

              • dolutegravir

                magnesium citrate will decrease the level or effect of dolutegravir by cation binding in GI tract. Avoid or Use Alternate Drug. Administer dolutegravir 2 hr before or 6 hr after taking medications containing polyvalent cations

              • doxycycline

                magnesium citrate decreases levels of doxycycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

              • eltrombopag

                magnesium citrate decreases levels of eltrombopag by inhibition of GI absorption. Applies only to oral form of both agents. Contraindicated. Separate by at least 4 hours.

              • minocycline

                magnesium citrate decreases levels of minocycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

              • oxytetracycline

                magnesium citrate decreases levels of oxytetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

              • potassium phosphates, IV

                magnesium citrate decreases effects of potassium phosphates, IV by cation binding in GI tract. Avoid or Use Alternate Drug. Magnesium decreases serum phosphate concentration by binding dietary phosphate. Use alternatives if available.

              • tetracycline

                magnesium citrate decreases levels of tetracycline by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

              Monitor Closely (16)

              • bictegravir

                magnesium citrate will decrease the level or effect of bictegravir by cation binding in GI tract. Modify Therapy/Monitor Closely. Bictegravir can be taken under fasting conditions 2 hr before antacids containing Al, Mg, or Ca. Routine administration of bictegravir simultaneously with, or 2 hr after, antacids containing Al, Mg, or Ca is not recommended.

              • cabotegravir

                magnesium citrate will decrease the level or effect of cabotegravir by cation binding in GI tract. Modify Therapy/Monitor Closely. Administer polyvalent cation products at least 2 hr before or 4 hr after taking oral cabotegravir.

              • ciprofloxacin

                magnesium citrate decreases levels of ciprofloxacin by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Coadministration of ciprofloxacin with multivalent cation-containing products may reduce the bioavailability of ciprofloxacin by 90%. Administer ciprofloxacin at least 2 hours before or 6 hours after using these products. Use alternatives if available.

              • deferiprone

                magnesium citrate decreases levels of deferiprone by enhancing GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Deferiprone may bind polyvalent cations (eg, iron, aluminum, and zinc), separate administration by at least 4 hr between deferiprone and other medications (eg, antacids), or supplements containing these polyvalent cations.

              • deflazacort

                magnesium citrate and deflazacort both decrease serum potassium. Use Caution/Monitor.

              • fleroxacin

                magnesium citrate decreases levels of fleroxacin by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

              • gemifloxacin

                magnesium citrate decreases levels of gemifloxacin by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

              • ifosfamide

                ifosfamide, magnesium citrate. Either increases toxicity of the other by nephrotoxicity and/or ototoxicity. Modify Therapy/Monitor Closely. Monitor electrolytes and renal function.

              • levofloxacin

                magnesium citrate decreases levels of levofloxacin by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

              • moxifloxacin

                magnesium citrate decreases levels of moxifloxacin by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

              • ofloxacin

                magnesium citrate decreases levels of ofloxacin by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

              • omadacycline

                magnesium citrate will decrease the level or effect of omadacycline by inhibition of GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Multivalent cation-containing products may impair absorption of tetracyclines, which may decrease its efficacy. Separate dosing of tetracyclines from these products.

              • penicillamine

                magnesium citrate decreases levels of penicillamine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

              • sarecycline

                magnesium citrate will decrease the level or effect of sarecycline by inhibition of GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Multivalent cation-containing products may impair absorption of tetracyclines, which may decrease its efficacy. Separate dosing of tetracyclines from these products.

              • sodium phosphates, IV

                magnesium citrate decreases effects of sodium phosphates, IV by cation binding in GI tract. Modify Therapy/Monitor Closely. Magnesium decreases serum phosphate concentration by binding dietary phosphate. Use alternatives if available.

              • vitamin D

                vitamin D increases levels of magnesium citrate by Other (see comment). Use Caution/Monitor. Comment: Vitamin D can increase serum magnesium concentrations, particularly in the presence of renal impairment. The combined use of vitamin D and magnesium-containing products should be avoided, if possible, in patients with chronic renal failure.

              Minor (41)

              • amikacin

                amikacin decreases levels of magnesium citrate by increasing renal clearance. Minor/Significance Unknown.

              • amiloride

                amiloride increases levels of magnesium citrate by decreasing renal clearance. Minor/Significance Unknown.

              • amphotericin B deoxycholate

                amphotericin B deoxycholate decreases levels of magnesium citrate by increasing renal clearance. Minor/Significance Unknown.

              • bazedoxifene/conjugated estrogens

                bazedoxifene/conjugated estrogens decreases levels of magnesium citrate by Other (see comment). Minor/Significance Unknown. Comment: Magnesium shifted from blood to tissue storage.

              • bendroflumethiazide

                bendroflumethiazide decreases levels of magnesium citrate by increasing renal clearance. Minor/Significance Unknown.

              • bumetanide

                bumetanide decreases levels of magnesium citrate by increasing renal clearance. Minor/Significance Unknown.

              • calcitonin salmon

                calcitonin salmon increases levels of magnesium citrate by decreasing renal clearance. Minor/Significance Unknown.

              • chlorothiazide

                chlorothiazide decreases levels of magnesium citrate by increasing renal clearance. Minor/Significance Unknown.

              • chlorthalidone

                chlorthalidone decreases levels of magnesium citrate by increasing renal clearance. Minor/Significance Unknown.

              • conjugated estrogens

                conjugated estrogens decreases levels of magnesium citrate by Other (see comment). Minor/Significance Unknown. Comment: Magnesium shifted from blood to tissue storage.

              • conjugated estrogens, vaginal

                conjugated estrogens, vaginal decreases levels of magnesium citrate by Other (see comment). Minor/Significance Unknown. Comment: Magnesium shifted from blood to tissue storage.

              • cyclopenthiazide

                cyclopenthiazide decreases levels of magnesium citrate by increasing renal clearance. Minor/Significance Unknown.

              • dextrose

                dextrose decreases levels of magnesium citrate by increasing renal clearance. Minor/Significance Unknown.

              • dextrose (Antidote)

                dextrose (Antidote) decreases levels of magnesium citrate by increasing renal clearance. Minor/Significance Unknown.

              • digoxin

                digoxin decreases levels of magnesium citrate by increasing renal clearance. Minor/Significance Unknown.

              • doxercalciferol

                doxercalciferol increases levels of magnesium citrate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

              • drospirenone

                drospirenone increases levels of magnesium citrate by decreasing renal clearance. Minor/Significance Unknown.

              • estradiol

                estradiol decreases levels of magnesium citrate by Other (see comment). Minor/Significance Unknown. Comment: Magnesium shifted from blood to tissue storage.

              • estrogens conjugated synthetic

                estrogens conjugated synthetic decreases levels of magnesium citrate by Other (see comment). Minor/Significance Unknown. Comment: Magnesium shifted from blood to tissue storage.

              • estrogens esterified

                estrogens esterified decreases levels of magnesium citrate by Other (see comment). Minor/Significance Unknown. Comment: Magnesium shifted from blood to tissue storage.

              • estropipate

                estropipate decreases levels of magnesium citrate by Other (see comment). Minor/Significance Unknown. Comment: Magnesium shifted from blood to tissue storage.

              • ethacrynic acid

                ethacrynic acid decreases levels of magnesium citrate by increasing renal clearance. Minor/Significance Unknown.

              • furosemide

                furosemide decreases levels of magnesium citrate by increasing renal clearance. Minor/Significance Unknown.

              • gentamicin

                gentamicin decreases levels of magnesium citrate by increasing renal clearance. Minor/Significance Unknown.

              • glucagon intranasal

                glucagon intranasal increases levels of magnesium citrate by decreasing renal clearance. Minor/Significance Unknown.

              • hydrochlorothiazide

                hydrochlorothiazide decreases levels of magnesium citrate by increasing renal clearance. Minor/Significance Unknown.

              • ibandronate

                magnesium citrate decreases levels of ibandronate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

              • indapamide

                indapamide decreases levels of magnesium citrate by increasing renal clearance. Minor/Significance Unknown.

              • mannitol

                mannitol decreases levels of magnesium citrate by increasing renal clearance. Minor/Significance Unknown.

              • mestranol

                mestranol decreases levels of magnesium citrate by Other (see comment). Minor/Significance Unknown. Comment: Magnesium shifted from blood to tissue storage.

              • methyclothiazide

                methyclothiazide decreases levels of magnesium citrate by increasing renal clearance. Minor/Significance Unknown.

              • metolazone

                metolazone decreases levels of magnesium citrate by increasing renal clearance. Minor/Significance Unknown.

              • neomycin PO

                neomycin PO decreases levels of magnesium citrate by increasing renal clearance. Minor/Significance Unknown.

              • nitrofurantoin

                magnesium citrate decreases levels of nitrofurantoin by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

              • paromomycin

                paromomycin decreases levels of magnesium citrate by increasing renal clearance. Minor/Significance Unknown.

              • sodium polystyrene sulfonate

                sodium polystyrene sulfonate increases levels of magnesium citrate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis.

              • spironolactone

                spironolactone increases levels of magnesium citrate by decreasing renal clearance. Minor/Significance Unknown.

              • streptomycin

                streptomycin decreases levels of magnesium citrate by increasing renal clearance. Minor/Significance Unknown.

              • tobramycin

                tobramycin decreases levels of magnesium citrate by increasing renal clearance. Minor/Significance Unknown.

              • torsemide

                torsemide decreases levels of magnesium citrate by increasing renal clearance. Minor/Significance Unknown.

              • triamterene

                triamterene increases levels of magnesium citrate by decreasing renal clearance. Minor/Significance Unknown.

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              Adverse Effects

              Frequency Not Defined

              Abdominal cramping

              Diarrhea

              Electrolyte imbalance

              Hypermagnesemia

              Gas formation

              Nausea/vomiting

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              Warnings

              Contraindications

              Low sodium diet

              Cautions

              For occasional use only in treatment of constipation; prolonged use for constipation may cause serious adverse effects

              To be used under the supervision of a physician when administered to patients with sodium or manesium restricted diet, kidney dysfunction, nausea/vomiting/abdominal pain with sudden change in bowel habits persisting over 2 weeks

              Use with caution in patients with myasthenia gravis or other neuromuscular disease

              Avoid use in renal failure, existing electrolyte imbalance, appendicitis or acute surgical abdomen, myocardial damage or heart block, fecal impaction or rectal fissures, intestinal obstruction or perforation, dehydration

              Discontinue use and consult healthcare provider if bowel movement does not occur or rectal bleeding develops

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              Pregnancy & Lactation

              Pregnancy category: A

              Lactation: Use in nursing mothers appears to be safe

              Pregnancy Categories

              A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

              B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

              C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

              D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

              X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

              NA: Information not available.

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              Pharmacology

              Mechanism of Action

              Increases peristaltic activity of the colon; promotes bowel evacuation by causing osmotic retention of fluid

              Absorption

              15-30% absorbed

              Onset: 0.5-6 hr or less

              Elimination

              Excretion: Urine (mainly)

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              Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.