magnesium gluconate (OTC)

Brand and Other Names:Mag-G, Magonate, more...Magtrate

Dosing & Uses


RDA (Elemental Magnesium)

Males: 400-420 mg PO qDay

18-30 (Females)

  • 310 mg PO qDay
  • Pregnancy: 350 mg PO qDay
  • Lactation: 310 mg PO qDay

>30 years (Females)

  • 320mg/day
  • Pregnant women: 360 mg/day
  • Lactating women: 320 mg/day


Liquid: 5-10 mL initially (first day)

Tablet: 2-4 tab initially (first day)

Titrate to higher dose until stool softens and remains soft; reduce intake if loose stool

Renal Impairment

CrCl <30 mL/min: Caution; reduce dose and monitor for hypermagnesemia

Magnesium Supplementation

Dietary reference for PO intake of elemental magnesium varies in children according to age

<6 months: 30 mg/day

6-12 months: 75 mg/day

1-3 years: 80 mg/day

3-8 years: 130 mg/day

8-13 years: 240 mg/day

Adolescent boys 13-18 years: 410 mg/day

Adolescent girls (13-18 years)

  • 360 mg/day
  • Pregnant: 400 mg/day
  • Lactating: 360 mg/day

Renal Impairment

CrCl <30 mL/min: Reduce dose and monitor for hypermagnesemia


Adverse Effects

Frequency Not Defined








Use caution in severe renal impairment

Use extreme caution in patients with myasthenia gravis or other neuromuscular diseases

May use for the treatment of constipation occasionally; prolonged use may result in serious side effects

Patient should inform physician about prescription nonprescription medications being taken, especially other products with magnesium or tetracycline

Inform physician about having or ever having kidney disease, intestinal disease, or stomach problems

If pregnant or planning to become pregnant or breastfeeding, discuss these with physician


Pregnancy & Lactation

Pregnancy Category: A; elemental magnesium dietary reference intake during pregnancy is 350-400 mg/day for adult women

Lactation: Distributed in breast milk, elemental magnesium dietary reference intake for breast feeding women is 310-360 mg/day for adult women

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.



Mechanism of Action

Cofactor for many enzymatic pathways involved in phosphate transfer reactions that use ATP and other nucleotides as substrates (eg, oxidative phosphorylation, oxygen radical reduction)


Absorption: 40-60% under controlled dietary conditions; 15-36% at higher doses; inversely proportional to amount ingested

Distribution: 50-60% bone; 1-2% extracellular fluid

Protein Bound: 30%

Excretion: Urine


Sources: meats, fish, poultry, eggs, dairy, nuts, legumes, cereals/grain

Functions: DNA/RNA synthesis; provides high energy phosphate bonds to ATP, CP, CHMP; cell membrane structure; cellular messenger; enzyme function; phosphate buffer system in IOF/renal tubules; part of hydroxyapatite structure in bone matrix

Deficiency: rare, can occur as phosphate binder reaction; ATP synthesis: abnormal neuromuscular, skeletal hematological and renal function

Toxicity: ion calcium: phosphorus from dietary intake; nutritional and hyperparathyroidism, increased bone turnover, decreased bone density/osteoporosis/fracture



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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.