What to Do When Iron Supplements Aren't Working

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Oral iron supplements are a common first-line strategy for addressing iron-deficiency anemia, a condition in which your body doesn’t have or doesn’t produce enough heathy red blood cells to carry oxygen throughout your body. Without enough iron, your red blood cells can’t produce enough hemoglobin, the substance that enables those cells to carry the oxygen to all your tissues. The goal of taking an oral supplement is to boost your body’s ability to produce that hemoglobin--and eventually your body’s iron stores.  

But oral iron supplements aren’t a silver bullet. At some point, you may find they’re not meeting your needs--and you may need to explore other options.

5 Things You Didn't Know About Anemia

The Benefits of Oral Iron Supplements … and the Drawbacks

When you have iron deficiency anemia, your doctor is likely to recommend a couple of strategies to address the problem:

  • Eat a diet rich in iron, which may include foods like legumes, leafy greens like collard greens and broccoli, certain types of fish, and meat (including organ meats like liver).

  • Take an oral iron supplement. Most people need 150-220 mg per day of elemental iron, according to the American Society of Hematology, but the recommended dose will vary for different people.

But this isn’t a perfect strategy. Your body only absorbs a small percentage of the iron in the food that you eat. (You’d have to eat a lot of kale and broccoli to get anywhere close to enough iron to make up for the difference.) And oral iron supplements aren’t a magic solution, either. 

Here are some of the reasons your doctor might want to look beyond oral iron supplements for your anemia treatment:

  • The supplement causes side effects. You might experience common side effects such as nausea, vomiting, abdominal discomfort, constipation and diarrhea, among others. At some point, this may become intolerable for you. In fact, many people stop taking their iron pills when the side effects become too much to bear.

  • Your body doesn’t absorb the iron from the supplements very well. To ward off some of those unpleasant gastrointestinal side effects, some doctors recommend enteric-coated iron pills. The trouble is, the coating can also decrease the effectiveness of the iron pills. You wind up not getting enough iron from the supplement to meet your needs.

  • You’re having trouble managing your med schedule. For example, some people need to take antacids, but then they have to stagger their schedule so they take the iron tablets a few hours before or after taking the antacids. Antacids can interfere with the body’s ability to absorb iron from the supplements, and some antacids contain calcium which also interefes. Depending on how much of the antacid they need to take, this could become hard to manage. Iron can also interact with other medication; for example, it’s been shown to reduce the efficacy of some medications to treat thyroid disorders.

  • You’re still suffering from iron deficiency. If you’re still suffering from anemia, despite faithfully taking your oral supplement, it may be time to try something else.

Next Step: Intravenous Iron

You and your doctor agree: oral iron supplements aren’t working for you. What’s next? In many circumstances, the next step is to try intravenous (IV) iron. With this treatment method, iron is delivered into a vein through a small tube known as a catheter. It may take several hours to complete the entire process, known as an infusion, in a hospital or clinic setting.  

IV iron treatment is often recommended for people who need to build up their body’s iron stores quickly. (The IV iron is delivered directly into the bloodstream much more rapidly than the iron in an oral supplement.) For example, doctors often suggest IV iron for people with iron-deficiency anemia as a result of bleeding in their gastrointestinal tract or have certain gastrointestinal disorders that prevent iron absorption.

But it may also be an option for you if you’ve tried the oral supplement route without success. The treatment regimen can vary, but you may need to receive several injections of iron to build up your body’s stores.

Another Option: Blood Transfusions

It takes time for the body to respond to iron supplementation and to start making healthy red blood cells. So, people who truly can’t wait, perhaps because of severe, life-threatening anemia, may be candidates for a blood transfusion because it shortens that time frame. The transfusion won’t cure the iron-deficiency anemia, but it will make sure the body receives that much-needed temporary influx of healthy red blood cells to carry oxygen throughout the body.

Ultimately, you and your doctor may have to monitor your iron levels to see what works for you. It could be that you could try going back to taking an oral iron supplement after receiving IV iron or a transfusion of red blood cells.

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2018 May 18
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