What are the recommended doses of Maalox (aluminum hydroxide/magnesium hydroxide) for adults and children, for both liquid suspension and chewable tablet forms, and what precautions should be observed?

Maalox Dosing Guidelines

Adult Dosing

For adults, Maalox (aluminum hydroxide/magnesium hydroxide) suspension is typically administered at 30 mL doses, given four times daily—1 hour after each main meal and at bedtime—though this regimen should be limited to short-term use due to aluminum toxicity risks. 1

Standard Liquid Suspension Regimen

• 30 mL per dose administered four times daily (after breakfast, lunch, dinner, and at bedtime) 1
• Doses should be taken 1 hour after meals and at bedtime for optimal acid neutralization 1
• This provides approximately 280 mEq of antacid per day when using standard formulations 2

Acid-Neutralizing Capacity

• Maalox suspensions demonstrate rapid onset of action, with most products neutralizing >90% of theoretical acid capacity within the estimated 15-minute gastric residence time 2
• The aluminum-to-magnesium ratio in commercial products ranges from 1:0.6 to 1:3.5, allowing selection based on desired balance between magnesium's laxative effect and aluminum's constipating effect 2

Pediatric Dosing

For children with gastroesophageal reflux, a dose of 700 mmol/1.73 m² body surface area per day has demonstrated clinical efficacy over an 8-week treatment period. 3

• This higher pediatric dose was effective in curing 12 of 15 children and improving symptoms in the remaining 3 patients 3
• Treatment significantly reduced total time with pH <4, number of reflux episodes, and episodes lasting >5 minutes on 24-hour pH monitoring 3

Critical Safety Precautions

Aluminum Toxicity Risk

• Chronic use of aluminum-containing antacids carries significant risk of aluminum accumulation, particularly in patients with renal impairment 4
• A cumulative dose difference of just 1 kg of aluminum hydroxide (equivalent to 2 capsules three times daily for 1 year) significantly predicts risk of aluminum bone disease 4
• Among dialysis patients ingesting aluminum hydroxide, 93% with serum aluminum >60 μg/L had bone aluminum content >60 μg/kg dry weight 4
• Avoid concomitant intake of citrate-containing compounds (e.g., Alka-Seltzer, Citracal), as citrate profoundly enhances aluminum absorption 4

Drug Interactions

• Administer Maalox at least 2 hours before or 4 hours after fluoroquinolone antibiotics to avoid severe reduction in antibiotic absorption 5, 6
• Concurrent administration with trovafloxacin reduced bioavailability by 66% when given simultaneously, but only 28% when Maalox was given 2 hours after the antibiotic 5
• Rufloxacin bioavailability decreased to 64% when Maalox was given 5 minutes before the antibiotic, versus 87% when given 4 hours after 6
• Ciprofloxacin absorption is reduced when taken with aluminum-containing antacids; separate administration by 1–2 hours before or 4 hours after Maalox 4

Sodium Content Considerations

• Sodium content varies widely among Maalox formulations, ranging from <2% to approximately 45% of the 500 mg daily sodium allowance for sodium-restricted diets 2
• Select low-sodium formulations for patients requiring sodium restriction 2

Formulation Considerations

Chewable Tablets

• While the evidence primarily addresses liquid suspensions, chewable tablet formulations are available 2
• Tablets should be thoroughly chewed before swallowing to maximize surface area for acid neutralization
• Liquid suspensions generally provide more rapid and complete acid neutralization compared to tablets within the 15-minute gastric residence time 2

Product Quality

• Approximately 4% of antacid suspension samples contain unacceptable bacterial counts 2
• Ensure products demonstrate content uniformity across lots, as this affects consistent therapeutic effect 2

Clinical Monitoring

When to Avoid Long-Term Use

• Limit duration of therapy due to cumulative aluminum toxicity risk, especially in patients with any degree of renal impairment 4
• Consider alternative acid-suppression strategies (H2-blockers, proton pump inhibitors) for chronic management 1
• In dialysis patients, even "low doses" of aluminum gels caused aluminum accumulation after only 1 year of use 4

No Acid Rebound Effect

• Despite historical concerns, standard doses of Maalox do not cause clinically relevant gastric acid rebound during the 2nd and 3rd post-dose hours or at night 1
• Both Maalox and calcium-containing antacids achieved identical increases in intragastric pH over 24 hours without rebound acidity 1