What should you not take Mylanta with?

October 14, 2025 •

4 min read

Antacids containing magnesium trisilicate and magnesium hydroxide can bind to drugs like tetracycline and fluoroquinolone antibiotics, impeding their absorption and therapeutic effects [1.9.4]. Understanding what you should not take Mylanta with is vital for avoiding negative health outcomes and ensuring your treatments work as intended.

Quick Summary

Mylanta can interact with numerous prescription and over-the-counter drugs, reducing their absorption and effectiveness. Key interactions include antibiotics, thyroid medication, and bisphosphonates.

Key Points

Primary Interaction Mechanism: Mylanta's active ingredients, aluminum and magnesium hydroxide, can bind to other drugs (chelation), significantly reducing their absorption and effectiveness [1.4.5].
Antibiotics: Do not take Mylanta with tetracycline or fluoroquinolone antibiotics, as it can lower their absorption by over 90% [1.4.5]. Separate doses by several hours [1.5.5].
Thyroid Medication: Mylanta interferes with the absorption of levothyroxine. Take thyroid medication at least 4 hours apart from Mylanta [1.6.2].
Osteoporosis Drugs: Bisphosphonates like alendronate are poorly absorbed and should be taken at least 30-60 minutes before Mylanta [1.7.1, 1.7.2].
General Dosing Rule: To minimize risks, take any other medication at least 2 hours before or 2 hours after taking Mylanta [1.8.5].
pH Alteration: By neutralizing stomach acid, Mylanta changes the stomach's pH, which can impair the absorption of drugs that require an acidic environment [1.9.4].
Consult a Professional: Always inform your doctor or pharmacist of all medications you are taking, including OTC products like Mylanta, to check for potential interactions [1.3.3].

Understanding Mylanta and Its Active Ingredients

Mylanta is a popular over-the-counter (OTC) medication used to treat symptoms of excess stomach acid, such as heartburn, acid indigestion, and upset stomach [1.8.3]. Its effectiveness comes from a combination of active ingredients: aluminum hydroxide, magnesium hydroxide, and simethicone. Aluminum hydroxide and magnesium hydroxide are antacids that work by neutralizing existing stomach acid [1.9.4]. They do not prevent acid production but provide rapid relief from its effects. Simethicone is an anti-gas agent that helps break up gas bubbles in the gut, relieving bloating and discomfort [1.6.2]. While effective for occasional relief, the components of Mylanta can interact with many other medications, which is why it's crucial to know what you should not take Mylanta with [1.8.5].

How Mylanta Causes Drug Interactions

The primary ways Mylanta interferes with other drugs are through two mechanisms: chelation and changing stomach pH.

Chelation and Reduced Absorption

The aluminum and magnesium in Mylanta are polyvalent cations, which can bind to other drugs in the gastrointestinal tract. This binding process, known as chelation, forms an insoluble complex that the body cannot absorb easily [1.4.5, 1.5.6]. When a drug is chelated, its journey into the bloodstream is halted, significantly reducing its bioavailability and effectiveness [1.4.1]. This means you may not get the therapeutic effect you need from your medication, which can lead to treatment failure [1.4.6].

Altering Stomach and Urinary pH

By neutralizing stomach acid, antacids increase the stomach's pH, making it less acidic. The absorption of many drugs depends on a specific pH environment [1.9.4]. For some medications, a less acidic stomach impairs their dissolution and subsequent absorption. Furthermore, changes in urinary pH can affect how quickly certain drugs are eliminated from the body by the kidneys, potentially leading to either reduced efficacy or increased risk of toxicity [1.9.4].

Key Medications That Interact with Mylanta

It is essential to space out doses of Mylanta and other medications to avoid interactions. A general rule is to take other medications at least 2 hours before or 2 hours after taking Mylanta, though some drugs may require a longer interval [1.8.1, 1.5.4].

Antibiotics: Tetracyclines and Fluoroquinolones

This is one of the most significant interactions. Both tetracycline antibiotics (e.g., doxycycline, tetracycline) and fluoroquinolone antibiotics (e.g., ciprofloxacin, levofloxacin) are prone to chelation by the aluminum and magnesium in Mylanta [1.4.3, 1.5.5]. This interaction can decrease the absorption of these antibiotics by more than 90%, rendering them ineffective against bacterial infections [1.4.5]. To prevent this, antibiotics should be taken 2 to 4 hours before or 4 to 6 hours after a dose of Mylanta [1.5.5].

Thyroid Medications

Levothyroxine (Synthroid), a medication used to treat hypothyroidism, requires an acidic environment for proper absorption. Antacids like Mylanta reduce stomach acid and can also bind to the medication, decreasing its absorption and effectiveness [1.6.3, 1.6.4]. This can lead to symptoms of an underactive thyroid, such as fatigue, weight gain, and depression [1.6.1]. It is recommended to take levothyroxine at least 4 hours before or after taking Mylanta to minimize this interaction [1.6.2, 1.6.5].

Bisphosphonates

Bisphosphonates, such as alendronate (Fosamax), are used to treat osteoporosis. Their oral absorption is already very low, and taking them with Mylanta can reduce it even further due to chelation [1.7.1, 1.7.5]. To ensure the medication is effective, you should take bisphosphonates at least 30 to 60 minutes before any other food, drink, or medication, including Mylanta [1.7.1, 1.7.2].

Other Significant Interactions

Iron Supplements: The aluminum and magnesium in antacids can decrease the absorption of iron supplements [1.3.3, 1.2.5]. Doses should be separated by at least 2 hours.
Certain Antifungals: Medications like ketoconazole and itraconazole require an acidic stomach to be absorbed properly. Mylanta can reduce their effectiveness.
Digoxin: Used for heart conditions, digoxin absorption can be reduced by antacids [1.2.2].
Pazopanib: An interaction with pazopanib, a cancer medication, is listed as severe [1.3.1].

Comparison Table of Mylanta Drug Interactions


Medication Class/Drug	Nature of Interaction	Recommended Management
Tetracycline Antibiotics	Chelation reduces antibiotic absorption by up to 90% [1.4.5].	Separate doses by at least 2-4 hours [1.4.1].
Fluoroquinolone Antibiotics	Chelation significantly inhibits antibiotic absorption [1.5.2].	Take antibiotic 2-4 hours before or 4-6 hours after Mylanta [1.5.5].
Thyroid Medications	Reduced absorption due to higher pH and binding [1.6.3].	Separate doses by at least 4 hours [1.6.2].
Bisphosphonates	Chelation severely decreases absorption [1.7.1].	Take bisphosphonate at least 30-60 minutes before Mylanta [1.7.2].
Iron Supplements	Reduced absorption of iron [1.3.3, 1.2.5].	Separate doses by at least 2 hours.

Conclusion: Safe Use of Mylanta

Mylanta is a helpful remedy for occasional acid indigestion, but its potential for drug interactions cannot be overlooked. The aluminum and magnesium hydroxides it contains can significantly impair the absorption and effectiveness of many critical medications by binding to them or altering stomach pH. The most critical interactions involve certain antibiotics, thyroid medications, and bisphosphonates, where the consequence of reduced drug efficacy can be severe [1.3.1, 1.4.5]. Always consult with a doctor or pharmacist about your complete medication list before using Mylanta [1.3.3]. To prevent issues, a general strategy is to separate the administration of Mylanta from other drugs by at least two to four hours [1.8.1, 1.6.5]. By being informed about what you should not take Mylanta with, you can use this antacid safely and effectively without compromising your other treatments.

For more detailed information on specific drug interactions, you can consult resources like the Drugs.com Interaction Checker.

Frequently Asked Questions

No, you should not take certain antibiotics like tetracyclines (e.g., doxycycline) and fluoroquinolones (e.g., ciprofloxacin) at the same time as Mylanta. Mylanta can bind to these antibiotics and severely reduce their absorption, making them ineffective. You should separate the doses by several hours [1.4.5, 1.5.5].

You should wait at least 4 hours after taking your thyroid medication, such as levothyroxine, before you take Mylanta. This waiting period is necessary because Mylanta can decrease the absorption of the thyroid hormone [1.6.2, 1.6.5].

While major interactions are less common, antacids can sometimes affect the absorption of other drugs. For instance, taking aspirin with certain antacids may reduce its absorption [1.2.5]. It's always best to check with your pharmacist, but generally, separating the doses by 2 hours is a safe practice [1.8.5].

Mylanta can interfere with the absorption of minerals like iron, zinc, and calcium found in multivitamins [1.2.5, 1.3.3]. To ensure you get the full benefit of your supplement, you should take your multivitamin at least 2 hours before or after taking Mylanta.

Taking Mylanta with food is generally acceptable. However, certain foods high in citrate (like citrus fruits and juices) can increase the absorption of aluminum from the antacid, which could be a concern for individuals with kidney problems [1.4.1]. The liquid form of Mylanta is often recommended to be taken without other fluids, but can be mixed with water if needed [1.2.2].

Mylanta contains aluminum hydroxide and magnesium hydroxide, which are antacids that neutralize stomach acid. It also contains simethicone, which helps to break down gas bubbles, relieving bloating and pressure [1.6.2].

To avoid potential interactions where Mylanta can make other medicines less effective, you should avoid taking any other medication within 2 hours before or 2 hours after you take Mylanta [1.8.5].