Does Maalox (aluminum hydroxide/magnesium hydroxide) cause QTc (corrected QT) interval widening?

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From the Guidelines

Maalox (aluminum hydroxide/magnesium hydroxide) does not cause QTc interval widening. This antacid combination is generally considered safe from a cardiac perspective and has no known direct effects on cardiac conduction or repolarization. Unlike some medications such as certain antibiotics (macrolides, fluoroquinolones), antipsychotics, and antiarrhythmics that can prolong the QT interval, Maalox works locally in the gastrointestinal tract by neutralizing stomach acid and has minimal systemic absorption. The small amounts of aluminum and magnesium that are absorbed do not affect cardiac ion channels responsible for QT interval regulation, as supported by the lack of mention in guidelines regarding QT-prolonging medications 1.

Some key points to consider:

  • Maalox can affect the absorption of other medications when taken simultaneously, so it should generally be separated by at least 2 hours from other drugs, especially those with known QT-prolonging effects.
  • If you have underlying cardiac conditions or are taking multiple medications, it's always advisable to consult with your healthcare provider, but Maalox itself is not a concern for QTc prolongation.
  • Maintaining normal potassium and magnesium balance is important, especially when medications or situations that promote depletion are encountered, as noted in the management of long QT syndrome 1.
  • The most recent guidelines emphasize the importance of avoiding QT-prolonging medications in patients with long QT syndrome unless there is no suitable alternative, and careful monitoring of the QTc during therapy is recommended 1.

Given the information provided and the current understanding of QT interval prolongation, Maalox does not pose a risk for QTc interval widening and can be used as needed for its intended purpose without concern for this specific cardiac risk.

From the Research

Maalox and QTc Interval Widening

  • There is no direct evidence in the provided studies that Maalox (aluminum hydroxide/magnesium hydroxide) causes QTc interval widening 2, 3, 4, 5, 6.
  • However, it is known that electrolyte disturbances, such as hypokalemia and hypomagnesemia, can contribute to QT interval prolongation 5, 6.
  • Maalox contains magnesium hydroxide, which can affect magnesium levels in the body, but there is no clear evidence that it can cause QTc interval widening.
  • The studies provided focus on the risks of QT interval prolongation associated with various drugs, including proton pump inhibitors 4, and the importance of considering patient-related risk factors and potential drug interactions 2, 3.
  • To determine the potential risk of QTc interval widening with Maalox, it would be necessary to consider individual patient factors, such as underlying medical conditions and concomitant medications, as well as monitor electrolyte levels and electrocardiogram (ECG) results.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Managing drug-induced QT prolongation in clinical practice.

Postgraduate medical journal, 2021

Research

Risk factors for QTc-prolongation: systematic review of the evidence.

International journal of clinical pharmacy, 2017

Research

Multifactorial QT interval prolongation.

Cardiology journal, 2010

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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