Maalox: Uses and Applications
Maalox (aluminum hydroxide/magnesium hydroxide) is primarily used as an antacid to neutralize stomach acid for treating heartburn, acid indigestion, and upset stomach, and can also function as a laxative in certain formulations.
Primary Uses of Maalox
- Maalox functions as an antacid that neutralizes stomach acid by combining aluminum hydroxide and magnesium hydroxide 1
- It provides faster relief of heartburn than H2-receptor antagonists like ranitidine, with meaningful heartburn relief occurring within 19 minutes versus 70 minutes for ranitidine 1
- Maalox is effective in treating duodenal ulcers, with high-dose regimens (three tablets twice daily) showing comparable efficacy to cimetidine in preventing duodenal ulcer relapse 2
- It can be used in treating gastric ulcers, with effectiveness comparable to H2-blockers, though healing time may be approximately 2 weeks longer 3
- Maalox is also effective for treating erosive gastroduodenitis and erosive reflux-esophagitis 4
Mechanism of Action
- Aluminum hydroxide and magnesium hydroxide in Maalox neutralize stomach acid, raising the gastric pH 4
- Beyond acid neutralization, Maalox may have cytoprotective effects on the gastroduodenal mucosa by increasing production of prostanoids and sulphydryl-containing compounds 3
- The aluminum component may stimulate endogenous prostaglandin synthesis, contributing to mucosal protection 5
Dosing Considerations
- For duodenal ulcer prevention, three tablets twice daily (morning and bedtime) has shown superior efficacy compared to bedtime-only dosing 2
- For heartburn relief, Maalox suspension provides rapid onset of action when used on-demand for acute symptoms 1
Special Populations and Precautions
- Magnesium-containing antacids like Maalox should be used with extreme caution or avoided in elderly patients with impaired renal function due to risk of hypermagnesemia 6
- In elderly patients with constipation, saline laxatives containing magnesium (including Maalox formulations with magnesium hydroxide) should be used cautiously, particularly in those with renal impairment 7
- For elderly patients with constipation, polyethylene glycol (PEG) at 17 g/day is generally recommended as a first-line treatment over magnesium-containing products 7
Potential Side Effects
- The most common side effect is diarrhea, which can occur due to the magnesium component 2
- Aluminum hydroxide in Maalox can be absorbed in small amounts by human gastric mucosa and accumulate in lysosomes, though studies have not observed histological damage to gastric mucosa 5
- Long-term use requires monitoring of serum magnesium and aluminum levels, though studies show no significant changes in these levels with regular use 2
Drug Interactions
- Maalox does not appear to affect the pharmacokinetics of certain medications like rivaroxaban, as studies show that aluminum-magnesium hydroxide antacids had no effect on plasma concentrations or pharmacodynamics of this anticoagulant 8
- Maalox should not be taken at the same time as other medications as it may affect their absorption 8