What is the recommended dose of Maalox (aluminum hydroxide/magnesium hydroxide) for a patient with heartburn or acid reflux symptoms, considering impaired renal function and potential interactions with other medications?

Maalox Dosing for Heartburn and Acid Reflux

Direct Answer

For symptomatic relief of heartburn, the standard dose of Maalox (aluminum hydroxide/magnesium hydroxide) is 2 teaspoonfuls (10 mL) taken 5-6 times daily after meals and at bedtime, not exceeding 12 teaspoonfuls (60 mL) in 24 hours, with maximum dosage duration limited to 2 weeks. 1

However, you should not be using Maalox as primary therapy for GERD—switch immediately to a proton pump inhibitor (PPI), which is significantly more effective than antacids for treating esophageal GERD syndromes. 2, 3

Why PPIs Are Superior to Antacids

• PPIs are more effective than H2-receptor antagonists (H2RAs), which are more effective than antacids, which are more effective than placebo for healing esophagitis and providing symptomatic relief in GERD. 2

• Antacids like Maalox provide rapid but short-lived relief (onset within 15-19 minutes but duration typically under 4 hours), making them suitable only for on-demand breakthrough symptom relief, not maintenance therapy. 4, 5

• The American Gastroenterological Association gives Grade A recommendation (strongly recommended based on good evidence) for antisecretory drugs (PPIs/H2RAs) over antacids for treating esophageal GERD syndromes. 2

Appropriate Use of Maalox

When Antacids Are Acceptable:

• For rapid on-demand relief of breakthrough heartburn while on PPI therapy—antacids work within 15-20 minutes compared to 60-70 minutes for H2RAs. 5

• As adjunctive therapy to PPIs for immediate symptom control, particularly alginate-containing antacids which provide mechanical barrier effects. 2, 3

Standard Dosing Protocol:

• Shake well before using 1

• 2 teaspoonfuls (10 mL) taken 5-6 times daily after meals and at bedtime 1

• Follow with a sip of water if needed 1

• Maximum: 12 teaspoonfuls (60 mL) in 24 hours 1

• Do not use maximum dosage for more than 2 weeks 1

Critical Considerations for Renal Impairment

In patients with impaired renal function, aluminum-containing antacids like Maalox pose significant risks:

• Aluminum is cleared almost exclusively by the kidneys, leading to accumulation and potential aluminum toxicity in renal insufficiency. 2

• While the tuberculosis guideline discusses streptomycin dosing in renal disease, the principle of reduced clearance of renally-eliminated medications applies equally to aluminum-containing antacids. 2

• Avoid chronic use of Maalox in patients with creatinine clearance <30 mL/min or those on dialysis due to aluminum accumulation risk.

• If antacid therapy is necessary in renal impairment, consider calcium carbonate-based antacids instead, though these also require monitoring for hypercalcemia.

Drug Interactions

Maalox significantly impairs absorption of multiple medications:

• Fluoroquinolone antibiotics: Concurrent administration with Maalox reduces trovafloxacin bioavailability by 66%, with relative bioavailability of only 50%. 6

• Spacing strategy: If Maalox must be used with interacting medications, administer Maalox 2 hours after the other medication to minimize interaction (reduces impact to 28% decrease in bioavailability versus 66% with concurrent dosing). 6

• Other commonly affected drugs include tetracyclines, iron supplements, levothyroxine, and certain cardiac medications—always check for interactions.

Recommended Treatment Algorithm

Step 1: Initial Therapy

• Start standard-dose PPI once daily (e.g., omeprazole 20 mg, lansoprazole 30 mg) taken 30-60 minutes before breakfast. 2, 3

• Allow 4-8 weeks for full therapeutic effect. 2, 3

Step 2: If Symptoms Persist

• Verify PPI compliance and timing (must be taken 30-60 minutes before meals, not with or after). 3

• Escalate to twice-daily PPI dosing (before breakfast and dinner). 2, 3

• Continue for 8 weeks. 3

Step 3: If Still Refractory

• Patient is a treatment failure—proceed to diagnostic workup with upper endoscopy and biopsies. 2, 3

• If endoscopy normal, perform esophageal manometry followed by ambulatory pH monitoring (withhold PPI for 7 days). 2

Adjunctive Maalox Use Throughout:

• Use Maalox 2 teaspoonfuls as needed for breakthrough symptoms while optimizing PPI therapy. 1, 5

• Limit to 2 weeks maximum at full dosing. 1

Common Pitfalls to Avoid

• Do NOT use Maalox as monotherapy for chronic GERD—this is inadequate treatment and delays appropriate PPI therapy. 2

• Do NOT exceed 12 teaspoonfuls (60 mL) in 24 hours or use maximum dosing beyond 2 weeks due to risk of electrolyte disturbances and aluminum accumulation. 1

• Do NOT use Maalox chronically in renal impairment (CrCl <30 mL/min) without close monitoring of aluminum levels. 2

• Do NOT administer Maalox concurrently with fluoroquinolones or other interacting medications—space by at least 2 hours. 6

• Do NOT continue empiric antacid therapy without establishing a diagnosis if symptoms persist despite appropriate PPI therapy—proceed to endoscopy. 2, 3

Monitoring Parameters

• Serum magnesium and aluminum levels if using Maalox for >2 weeks, especially in elderly or renally impaired patients. 7

• Renal function (creatinine, BUN) at baseline and periodically if chronic use is necessary. 2

• Watch for diarrhea (occurs in approximately 12% of patients on chronic antacid therapy). 7