magnesium antacids

magnesium hydroxide : mag-NEE-zhum hye-DROX-ide

magnesium oxide: mag-NEE-zhum OX-ide

Classifications ⬆ ⬇

Therapeutic Classification: mineral and electrolyte replacements/supplements, laxatives

Pharmacologic Classification: salines

Indications ⬆ ⬇

REMS

Treatment/prevention of hypomagnesemia.
As a:
- Laxative,
- Bowel evacuant in preparation for surgical/radiographic procedures.
Milk of Magnesia has also been used as an antacid.

Action ⬆ ⬇

Essential for the activity of many enzymes.
Play an important role in neurotransmission and muscular excitability.
Are osmotically active in GI tract, drawing water into the lumen and causing peristalsis.

Therapeutic effects:

Replacement in deficiency states.
Evacuation of the colon.

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 ⬆ ⬇

( laxative effect)

ROUTE	ONSET	PEAK	DURATION
PO	3–6 hr	unknown	unknown

Contraind./Precautions ⬆ ⬇

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, and tetracyclines and penicillamine.

Route/Dosage ⬆ ⬇

Antacid

PO (Adults ): Magnesium oxide: 140 mg 3–4 times/day or 400–840 mg/day; Magnesium hydroxide (Milk of Magnesia): 5–15 mL/dose up to 4 times/day as liquid or 2.5–7.5 mL/dose up to 4 times/day as liquid concentrate mg/dose or 622–1244 mg/dose (2–4 tabs) up to 4 times/day.
PO (Children ): Magnesium hydroxide (Milk of Magnesia): 2.5–5 mL/dose up to 4 times/day as liquid or 311 mg (1 tab) up to 4 times/day.

Availability ⬆ ⬇

Magnesium Hydroxide

(Generic available)

Liquid: 400 mg/5 mL (164 mg magnesium/5 mL)^OTC
Concentrated liquid: 800 mg/5 mL (328 mg magnesium/5 mL)^OTC
Chewable tablets: 300 mg (130 mg magnesium)^OTC; 600 mg (260 mg magnesium)^OTC

Magnesium Oxide

(Generic available)

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

Assessment ⬆ ⬇

Antacid: Assess for heartburn and indigestion as well as location, duration, character, and precipitating factors of gastric pain.

Implementation ⬆ ⬇

PO: To prevent tablets entering small intestine in undissolved form, they must be chewed thoroughly before swallowing. Follow with ½ glass of water.
- Magnesium hydroxide: Shake solution well before administration.
Antacid: Administer 1–3 hr after meals and at bedtime.
- Powder and liquid forms are considered more effective than tablets.

Patient/Family Teaching ⬆ ⬇

Advise patient not to take this medication within 2 hr of taking other medications, especially fluoroquinolones, nitrofurantoin, and tetracyclines.
Antacids: Caution patient to consult health care professional before taking antacids for more than 2 wk if problem is recurring, if relief is not obtained, or if symptoms of gastric bleeding (black, tarry stools; coffee-ground emesis) occur.

Evaluation/Desired Outcomes ⬆ ⬇

Relief of gastric pain and irritation.

US Brand Names ⬆

magnesium hydroxide : Dulcolax Magnesia Tablets, Phillips Magnesia Tablets, Phillips Milk of Magnesia, MOM,

magnesium oxide: Mag-Ox 400, Uro-Mag

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Pronunciation ⬇