magnesium supplements (oral)

Contraindicated in:

Hypermagnesemia;
Hypocalcemia;
Anuria;
Heart block;
Active labor or within 2 hr of delivery (unless used for preterm labor).

Use Cautiously in:

Any degree of renal insufficiency.

Adv. Reactions/Side Effects ⬆ ⬇

Derm: flushing, sweating

GI: diarrhea

Interactions ⬆ ⬇

Drug-drug:

Potentiates neuromuscular blocking agents.
May decrease absorption of fluoroquinolones, nitrofurantoin, tetracyclines, and penicillamine.

Availability ⬆ ⬇

Magnesium Chloride

Sustained-release tablets: 535 mg (64 mg magnesium)^OTC
Enteric-coated tablets: 833 mg (100 mg magnesium)^OTC

Magnesium Gluconate

Tablets: 500 mg^OTC
Liquid: 54 mg/5 mL^OTC

Magnesium Oxide

(Generic available)

Tablets: 400 mg (241.3 mg magnesium)^OTC
Capsules: 140 mg (84.5 mg magnesium)^OTC

Route/Dosage ⬆ ⬇

500 mg magnesium chloride = 59 mg elemental magnesium = 4.9 mEq magnesium. 500 mg magnesium gluconate = 27 mg elemental magnesium = 2.4 mEq magnesium. 500 mg magnesium oxide = 302 mg elemental magnesium = 25 mEq magnesium.

Hypomagnesemia

PO (Adults ): Magnesium gluconate: 500–1000 mg 3 times/day;Magnesium oxide: 400–800 mg daily (Mag-Ox 400) or 140–280 mg 3 times daily (Uro-Mag);Magnesium chloride: 54–483 mg/day in divided doses.
PO (Children ): 10–20 mg/kg elemental magnesium per dose 4 times/day.

Recommended Daily Allowance

PO (Adults and Children >9 yr): Males: 200–400 mg elemental magnesium/day; Females: 200–310 mg elemental magnesium/day;pregnant women: 320 mg elemental magnesium/day; breastfeeding women: 340–355 mg elemental magnesium/day.
PO (Children 4–8 yr): 110–130 mg elemental magnesium/day.
PO (Children 1–3 yr): 65–80 mg elemental magnesium/day.
PO (Infants 6–12 mo): 60–75 mg elemental magnesium/day.
PO (Infants <6 mo): 30–40 mg elemental magnesium/day.

US Brand Names ⬆ ⬇

magnesium chloride : Mag Delay, Mag-SR, Slo-Mag,

magnesium gluconate : Almoate, Magtrate, Magonate,

magnesium oxide : Mag-Ox 400, Uro-Mag

Action ⬆ ⬇

Essential for the activity of many enzymes.
Play an important role in neurotransmission and muscular excitability.

Therapeutic effects:

Replacement in deficiency states.

Classifications ⬆ ⬇

Therapeutic Classification: mineral and electrolyte replacements/supplements

Pharmacokinetics ⬆ ⬇

Absorption: Up to 30% may be absorbed orally.

Distribution: Widely distributed. Cross the placenta and are present in breast milk.

Metabolism/Excretion: Excreted primarily by the kidneys.

Half-Life: Unknown.

Time/Action Profile ⬆ ⬇

ROUTE	ONSET	PEAK	DURATION
PO	3–6 hr	unknown	unknown

Patient/Family Teaching ⬆ ⬇

Advise patient not to take this medication within 2 hr of taking other medications, especially fluoroquinolones, nitrofurantoin, and tetracyclines.

Pronunciation ⬆

magnesium chloride : mag-NEE-zhum KLOR -ide

magnesium gluconate : mag-NEE-zhum GLOO-con-ate

magnesium oxide : mag-NEE-zhum OX-ide

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Indications ⬇

Contraind./Precautions ⬆ ⬇