What is the appropriate dosage and frequency of Maalox (aluminum hydroxide/magnesium hydroxide) for a patient requiring antacid therapy?

Maalox Dosing for Antacid Therapy

For adults requiring antacid therapy with Maalox (aluminum hydroxide/magnesium hydroxide), the standard prescription is 2 teaspoonfuls (approximately 10 mL) taken 5-6 times daily after meals and at bedtime, not exceeding 12 teaspoonfuls in 24 hours, with maximum dosage duration limited to 2 weeks. 1

Standard Dosing Regimen

• Shake the suspension well before each use to ensure proper distribution of active ingredients 1
• Administer 2 teaspoonfuls (10 mL) per dose, taken 5-6 times throughout the day 1
• Timing: After each meal and at bedtime to neutralize postprandial acid and provide overnight protection 1
• Follow each dose with a sip of water if needed to aid swallowing and distribution 1

Maximum Dosage Limits

• Do not exceed 12 teaspoonfuls (60 mL) in any 24-hour period 1
• Maximum duration at full dosage: 2 weeks 1
• If symptoms persist beyond 2 weeks, re-evaluation for alternative therapy (H2-receptor antagonists or proton pump inhibitors) is warranted 2

Clinical Context and Evidence

The 2022 AGA guidelines position antacids, including aluminum/magnesium hydroxide combinations, as adjunctive therapy for breakthrough GERD symptoms rather than primary treatment 2. Alginate-containing antacids are particularly useful for neutralizing the postprandial acid pocket and may be especially beneficial for patients with post-prandial or nighttime symptoms and those with hiatal hernia 2.

Research demonstrates that Maalox at higher doses (81-162 mmol daily) can be effective for duodenal ulcer maintenance, with 162 mmol daily (approximately 3 tablets twice daily in tablet formulation) showing efficacy comparable to cimetidine 400 mg at bedtime 3. However, the liquid formulation prescribed at standard FDA-approved doses provides symptomatic relief rather than ulcer healing 1.

Critical Safety Considerations

Hypermagnesemia Risk

• Patients with bowel obstruction, renal impairment, or those taking multiple magnesium-containing products are at significant risk for life-threatening hypermagnesemia 4
• Even patients with normal renal function can develop severe hypermagnesemia (>9 mEq/L) when gastrointestinal motility is impaired 4
• Monitor for confusion, hypotension, hypothermia, and cardiac conduction abnormalities in at-risk patients 4

Aluminum Accumulation

• Chronic use can lead to aluminum accumulation, though clinical significance at standard doses for 2 weeks is minimal 3
• Avoid prolonged use beyond 2 weeks at maximum dosage 1

Drug Interactions

• Antacids can significantly impair absorption of many medications including tetracyclines, fluoroquinolones, and iron supplements 2
• Administer other medications at least 2 hours before or after antacid doses to minimize interactions

When to Transition to Alternative Therapy

If symptoms require continuous antacid use beyond 2 weeks, transition to acid suppression therapy:

• H2-receptor antagonists for mild-moderate symptoms 2
• Proton pump inhibitors for erosive esophagitis or severe GERD 2
• The 2022 AGA guidelines emphasize that antacids should not be used as monotherapy for confirmed GERD requiring long-term management 2

Pediatric Considerations

For pediatric GERD, antacids provide limited historical evidence of symptom relief but are not recommended as primary therapy 2. The 2013 AAP guidelines note concerns about overprescription and recommend considering acid suppressants (H2RAs or PPIs) for documented GERD in children rather than relying on antacids 2.

In children with gastroesophageal reflux, high-dose antacid therapy (700 mmol/1.73 m²/day) has shown efficacy, but this far exceeds standard adult dosing and requires specialized monitoring 5.