magnesium hydroxide/aluminum hydroxide

REMS

Useful in a variety of GI complaints, including:
- Hyperacidity,
- Indigestion,
- GERD,
- Heartburn.

Contraind./Precautions ⬆ ⬇

Contraindicated in:

Severe abdominal pain of unknown cause, especially if accompanied by fever
Renal failure (CrCl <30 mL/min)
Products containing tartrazine or sugar in patients with known intolerance.

Use Cautiously in:

Antacids containing magnesium in patients with any degree of renal insufficiency
↓bowel motility
Dehydration
Upper GI hemorrhage
Children <12 yr (safety not established).

Adv. Reactions/Side Effects ⬆ ⬇

GI: aluminum salts: constipation.
magnesium salts: diarrhea.

F and E: magnesium salts: hypermagnesemia.
aluminum salts: hypophosphatemia.

Interactions ⬆ ⬇

Drug-Drug:

Absorption of tetracyclines, phenothiazines, ketoconazole, itraconazole, iron salts, fluoroquinolones, and isoniazid may be ↓ (separate by at least 2 hr).

Availability ⬆ ⬇

(Generic available)

Chewable Tablets: 300 mg aluminum hydroxide/150 mg magnesium hydroxide^OTC;
Suspension: 225 mg aluminum hydroxide/200 mg magnesium hydroxide/5 mL^OTC; 500 mg aluminum hydroxide/500 mg magnesium hydroxide/5 mL^OTC;
In combination with: simethicone^OTC. See Appendix [not included in this PDA edition].

Route/Dosage ⬆ ⬇

PO (Adults and Children 12 yr): 5–30 mL or 1–2 tablets 1–3 hr after meals and at bedtime.

US Brand Names ⬆ ⬇

Alamag, Maalox, Mylanta Ultimate, Rulox

Action ⬆ ⬇

Neutralize gastric acid following dissolution in gastric contents.
Inactivate pepsin if pH is raised to 4.

Therapeutic Effects:

Neutralization of gastric acid with healing of ulcers and decrease in associated pain.

Classifications ⬆ ⬇

Therapeutic Classification: antiulcer agents

Pharmacologic Classification: antacids

Pharmacokinetics ⬆ ⬇

Absorption: During routine use, antacids are nonabsorbable. With chronic use, 15–30% of magnesium and smaller amounts of aluminum may be absorbed.

Distribution: Small amounts absorbed are widely distributed, cross the placenta, and appear in breast milk. Aluminum concentrates in the CNS.

Metabolism/Excretion: Excreted by the kidneys.

Half-life: Unknown.

Canadian Brand Names ⬆ ⬇

Time/Action Profile ⬆ ⬇

ROUTE	ONSET	PEAK	DURATION
Aluminum PO	slightly delayed	30 min	30 min-1 hr (empty stomach); 3 hr (after meals)
Magnesium PO	slightly delayed	30 min	30 min-1 hr (empty stomach); 3 hr (after meals)

Patient/Family Teaching ⬆ ⬇

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.
Advise patient not to take this medication within 2 hr of taking other medications.
Pedi: Aluminum- or magnesium-containing medicines can cause serious side effects in children, especially when given to children with renal disease or dehydration. Advise parents or caregivers not to administer OTC antacids to children without consulting health care professional.

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Indications ⬇