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
Supplement
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
Diarrhea
Warnings
Contraindications
Hypersensitivity
Hypermagnesemia
Cautions
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.Pharmacology
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)
Pharmacokinetics
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
Nutrition
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
