8 Iron Supplement Interactions: Dairy, Coffee, Antibiotics, and More
Key takeaways:
Most oral iron supplements are available over the counter (OTC). Other iron products, such as infusions, are available with a prescription. Oral iron supplements can interact with several medications and foods.
Iron supplements can reduce the absorption of some medications, such as tetracycline antibiotics, levothyroxine, and bisphosphonates. Other items can lower your body’s absorption of iron, such as heartburn medications, dairy products, and coffee.
Oftentimes, iron supplement interactions can be managed by spacing out your iron supplement until at least 2 hours before or after certain medications and foods. Check with your pharmacist about your specific medication.
Your healthcare team can make recommendations to help you avoid potential iron supplement interactions. Make sure to check with them before starting OTC iron supplements, and provide a current medication list for their review.
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Table of contents
You’ve probably seen a variety of iron supplements available at your local pharmacy. Oral iron supplements come in several forms, such as ferrous sulfate, ferrous fumarate, and ferrous gluconate. You can find most of them over the counter (OTC). So, they’re easily accessible. Other forms of iron, such as iron infusions, are available with a prescription.
Iron supplements can help treat health conditions such as iron-deficiency anemia. But before you start taking one, there are several interactions to know about. That’s because iron supplements can affect how some medications work. And other medications, foods, and drinks can affect how well your body absorbs iron, too. In fact, it’s best to take your iron supplement first thing in the morning on an empty stomach, if possible.
Before you start taking an iron supplement, it’s a good idea to check with your healthcare team. Be sure to provide your current medication list for their review. That way, they can help ensure you’re getting the right amount of iron and taking it safely. Below, we cover eight notable iron supplement interactions and how to manage them.
1. Antibiotics such as tetracycline
Tetracycline antibiotics are a class of antibiotics. Examples of medications in this class include tetracycline, doxycycline (Vibramycin), and minocycline (Minocin). Iron can bind to these medications and prevent them from being absorbed. This can result in lower antibiotic levels in the body, making them less effective.
Spacing out tetracycline antibiotics and iron supplements can help prevent this interaction. It’s recommended that you take tetracycline antibiotics at least 2 hours before or 4 hours after taking iron.
2. Heartburn medications such as Tums, Pepcid, or Prilosec
Iron supplements are best absorbed when there’s enough acid in the stomach. But stomach acid sometimes causes unpleasant symptoms, such as heartburn, when it travels back into the esophagus. If you’re dealing with heartburn, you may turn to medications that lower or neutralize the acid. However, these medications also reduce the absorption of iron.
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Examples of heartburn medications that can interact with iron supplements include:
Antacids such as Tums (calcium carbonate)
H2 blockers such as famotidine (Pepcid)
Proton pump inhibitors (PPIs) such as omeprazole (Prilosec) or pantoprazole (Protonix)
If you need heartburn treatment, your healthcare team can make recommendations to help you relieve your symptoms safely while taking iron. They may suggest taking iron up to 2 hours before heartburn medication so there’s more acid in your stomach. Or, they may adjust your oral iron dose to make sure you’re getting enough.
3. Bisphosphonates such as Fosamax
Oral bisphosphonates such as Fosamax (alendronate) help treat osteoporosis. But you must follow specific instructions to maximize their effectiveness. For example, you need to take them with a full glass of water at least 30 or 60 minutes before your first food or drink of the day. You should also avoid taking bisphosphonates at the same time as iron. Iron lowers the absorption of bisphosphonates, which can make them less effective.
The solution is timing your bisphosphonate dose and your iron supplement. You could take your iron at a different time of day than your bisphosphonate. Or, your healthcare team can advise how far apart you should separate iron from your bisphosphonate, depending on the medication. They can help you find a dosage schedule to get the most benefit out of both medications.
4. Levothyroxine
Levothyroxine (Synthroid) is a common and effective treatment for hypothyroidism. It’s also notorious for having many interactions. Iron is one of them. Taking iron supplements too close to your levothyroxine dose can lower how much levothyroxine you absorb.
If you need to take levothyroxine and iron supplements, your healthcare team will likely suggest taking levothyroxine at least 4 hours apart from iron.
5. NSAIDs such as ibuprofen
Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Advil, Motrin) can help manage pain and inflammation. But they also carry risks, including stomach ulcers and bleeding, which can lead to iron deficiency and anemia. This can counteract the benefits you may get from taking iron. What’s more, iron can also irritate the stomach or intestines.
Since both iron and NSAIDs can be hard on the stomach, it’s a good idea to avoid the combination if possible. Your healthcare team may suggest an alternative pain reliever that’s safer to use with iron, such as acetaminophen (Tylenol).
6. Captopril
Captopril is an angiotensin-converting enzyme (ACE) inhibitor. It’s used to treat health conditions such as high blood pressure. Food, as well as iron, can decrease the amount of captopril your body absorbs.
Taking iron at least 2 hours before or 2 hours after captopril can help you get the most benefit from both medications.
7. Dairy products
Dairy products are common foods in most diets. Milk, yogurt, and cheese, among other dairy products, can be part of a healthy diet. But they can also interact with several medications, including iron. This is because dairy products are often rich in calcium. And calcium binds to iron in the stomach and prevents it from being absorbed.
Fortunately, spacing out your iron supplement away from dairy products can help you avoid this problem. It’s recommended that you take iron either 2 hours before or 2 hours after consuming dairy products.
8. Coffee
Coffee is another culprit that can interfere with how much iron you absorb. This is because it contains certain chemicals, such as polyphenols, that bind to iron. Tea also contains these chemicals, so it may also reduce iron absorption. Orange juice is a better drink option due to its ascorbic acid content, which can help you absorb more iron from your dose.
Does this mean you need to avoid coffee altogether? Not necessarily. But after you’ve taken your iron supplement, it may be a good idea to hold off on coffee or tea for a couple hours.
The bottom line
Iron supplements are common and widely available over the counter (OTC). But iron has lots of possible drug interactions. Examples include tetracycline antibiotics, bisphosphonates, and levothyroxine. Nonsteroidal anti-inflammatory drugs (NSAIDs), stomach acid-lowering medications, and dairy products also commonly interact with iron supplements.
Generally, iron supplement interactions either lower the amount of iron your body absorbs or lower the amount of the other medications you absorb. In some cases, spacing out iron either 2 hours before or after the interacting product can help minimize interactions. Talk with your healthcare team or pharmacist if you have questions about taking iron supplements safely.
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