About iron supplements for chronic kidney disease
Iron is a mineral your body needs to make healthy red blood cells and maintain your overall health. Iron is found in a wide variety of foods. It is also available as a medication/supplement for people who don’t get enough in their diet. Not having enough iron in your body is also called “iron deficiency”. Iron deficiency is a common cause of anemia (low level of red blood cells) in people with chronic kidney disease (CKD).
Uses
Iron is used to help treat or prevent anemia. People living with CKD often have low levels of iron, especially if you:
- Live with stage 4 CKD or stage 5 CKD (kidney failure)
- Receive anemia treatments known as “erythropoietin-stimulating agents” (ESAs), such as Epogen, Procrit, Retacrit, Aranesp, or Mircera
- Receive hemodialysis treatments
- Have received a kidney transplant
- Experience blood loss not related to CKD, such as menstruation (having your period), colon polyps (fleshy growths on the lining of your colon), or hemorrhoids (swelling in your anus)
- Are not able to get enough iron from your diet
- Have pica [PIE-kuh] (a condition where people crave things that are not food, like paint chips, dirt, ice, paper, sand, or chalk)
CKD can make it hard for your body to absorb iron from your diet or eat foods that are high in iron. So, even if you feel you are getting enough iron in your meals, your healthcare professional may recommend iron treatment to boost your iron levels and help treat anemia.
How it works
Iron is an important ingredient your body needs to make hemoglobin (red blood cells). Red blood cells carry oxygen from your lungs to all parts of your body. They give you the energy needed for all your daily activities. Your kidneys play an important role in helping your body make red blood cells. Iron treatments work by helping make sure your body has enough iron to do this important work.
Types
Iron supplements come in two forms: tablets or liquids that are taken by mouth, and a liquid that is given through a vein (intravenously or IV).
Iron tablets/liquids taken by mouth
There are many different options to choose from, and most are available “over the counter” (without a prescription). Iron tablets/liquids usually need to be taken 2-4 times per day depending on the product.
Even though many iron products are available without a prescription, do not start one without talking with your healthcare professional first.
Some examples include (listed in order from highest to lowest iron content in each tablet):
- Ferric citrate (Auryxia)
- Ferrous fumarate (Ferretts, Ferrimin 150)
- Ferrous sulfate (Slow FE, Fer-In-Sol, Feosol, Feratab)
- Ferrous gluconate (Fergon, Ferate, Ferralet, Simron)
- Ferric maltol (Accrufer)
- Liposomal iron
- Heme iron polypeptide
Iron given through a vein (IV)
These are only available with a prescription and need to be given by a trained healthcare professional (usually at a doctor’s office, dialysis clinic, or infusion center).
Some examples include:
- Ferric carboxymaltose (Injectafer)
- Ferric derisomaltose (Monoferric)
- Ferric gluconate (Ferrlecit)
- Ferumoxytol (Feraheme)
- Iron dextran (INFeD)
- Iron sucrose (Venofer)
Fun fact: the Latin word for iron is “ferrum”. This is why many products containing iron include “ferr” in their names.
Effectiveness
Iron treatments can be very effective for treating low levels of iron. Iron taken by mouth will take longer to increase your iron levels, while IV iron works faster. As CKD progresses, it can lower your body’s ability to absorb (take in) iron from your stomach. So, IV iron may be more effective for people in later stages of CKD, especially if you are getting hemodialysis treatments. It may also be more convenient for people on hemodialysis because it can be given at the same time as your dialysis treatments.
Iron tablets/liquids also have other factors impacting their effectiveness. These include:
- Your body is limited by how much iron it can absorb from your stomach at the same time. So, it may be necessary to take multiple doses of iron throughout the day.
- Food can lower your body’s ability to absorb iron, especially foods that are high in calcium or fiber. Taking iron on an empty stomach can help your body absorb it but increases the risk of side effects.
- Some supplements can also block your body’s ability to absorb iron. These include calcium, zinc, and magnesium. So, iron should be taken at least 2 hours before or 2 hours after supplements for calcium, zinc, or magnesium.
- Iron is more easily digested in an acidic environment. So, people who are taking medicine for acid reflux (heart burn) like antacids, H2 blockers, or proton pump inhibitors (PPIs) may have difficulty absorbing iron. If you are taking an antacid, your healthcare professional may recommend separating your iron from your antacid by at least 4 hours. If you are taking an H2 blocker or PPI, you may be advised to take your iron with a vitamin C supplement or acidic drink (such as orange juice).
Side effects
The side effects of iron depend on how the treatment is given.
Iron taken by mouth can cause constipation, nausea, diarrhea, stomach cramping, and passing gas. Taking iron with food can lower the risk of these side effects but also lowers the amount of iron your body will absorb with each dose. It is also common for unabsorbed iron to cause dark or black stools. These are to be expected and usually not cause for concern.
Intravenous (IV) iron can cause dizziness, flushing (getting red in the face or neck), low blood pressure, chest tightness, itching, and muscle or joint pain. A sudden life-threatening allergic reaction is possible, though not very common. This is why IV iron treatments are given by a trained healthcare professional in a healthcare setting – to be ready to step in quickly. Fortunately, the risk is much lower with modern IV treatments when compared to older iron products that are no longer available in the United States.
While not common, it is possible to get too much iron - also known as “iron overload”. So, be sure to complete your regular lab monitoring (blood tests) as recommended by your healthcare professional.
Questions for your healthcare team
- What is my level of risk for iron deficiency (low iron levels)?
- Not everyone living with CKD is at high risk for iron deficiency. So, ask your healthcare professional what your level of risk is and whether you should be tested.
- Should I be taking iron supplements? If so, which one(s) do you think would be most effective for me?
- There are so many options for people who need treatment with iron supplements, including many different types of iron tablets/liquids and IV iron products. The “best” treatment for you will depend on your situation and personal preferences.
- How often should I get lab work done to monitor my anemia (including my iron-specific labs)?
- How often you should have your labs checked depends on many factors, including your stage of CKD, other health conditions, other medications/treatments you are taking, and how easy it is for you to get your labs drawn.
- Are there any special instructions I should follow when taking my iron supplement?
- Remember, some foods, supplements, and medications can lower your ability to absorb (take in) iron from your stomach. Iron can also interfere with other medications and decrease their effectiveness. How much this may affect you depends on your usual eating habits and other medications or supplements you are taking. The best approach to maximize the effectiveness of your iron supplement and lower the risk of drug interactions highly depends on your situation.
