Oral iron supplements are the best way to restore iron levels for people who are iron deficient, but they should be used only when dietary measures have failed. Iron supplements cannot correct anemias that are not due to iron deficiency.
Iron replacement therapy can cause gastrointestinal problems, sometimes severe ones. Excess iron may also contribute to heart disease, diabetes, and certain cancers. Experts generally advise against iron supplements in anyone with a healthy diet and no indications of iron deficiency anemia.
Treatment of Anemia of Chronic Disease
In general, the best treatment for anemia of chronic diseases is treating the disease itself. In some cases, iron deficiency accompanies the condition and requires iron replacement. Erythropoietin, most often administered with intravenous iron, is used for some people.
Oral Iron Supplements
There are two forms of supplemental iron: ferrous and ferric. Ferrous iron is better absorbed and is the preferred form of iron tablets. Ferrous iron is available in 3 forms:
- Ferrous fumarate
- Ferrous sulfate
- Ferrous gluconate
The label of an iron supplement contains information both on the tablet size (which is typically 325 mg) and the amount of elemental iron contained in the tablet (the amount of iron that is available for absorption by the body.) When selecting an iron supplement, it is important to look at the amount of elemental iron.
A 325 mg iron supplement contains the following amounts of elemental iron depending on the type of iron:
- Ferrous fumarate. 108 mg of elemental iron
- Ferrous sulfate. 65 mg of elemental iron
- Ferrous gluconate. 35 mg of elemental iron
Depending on the severity of your anemia, as well as your age and weight, your health care provider will recommend a dosage of 60 to 200 mg of elemental iron per day. This means taking 1 iron pill 2 to 3 times during the day. Make sure your provider explains to you how many pills you should take in a day and when you should take them. Never take a double dose of iron.
Side Effects and Safety
Common side effects of iron supplements include:
- Constipation and diarrhea are very common. They are rarely severe, although iron tablets can aggravate existing gastrointestinal problems such as ulcers and ulcerative colitis.
- Nausea and vomiting may occur with high doses, but taking smaller amounts of medicine can control the problem. Switching to ferrous gluconate may help some people with severe gastrointestinal problems.
- Black stools are normal when taking iron tablets. In fact, if they do not turn black, the tablets may not be working effectively. This problem tends to be more common with coated or long-acting iron tablets.
- If the stools are tarry looking as well as black, if they have red streaks, or if cramps, sharp pains, or soreness in the stomach occur, gastrointestinal bleeding may be causing the iron deficiency. You should contact your health care provider right away.
- Acute iron poisoning is rare in adults but can be fatal in children who take adult-strength tablets. Keep iron supplements out of the reach of children. If your child swallows an iron pill, immediately contact a poison control center.
Other Tips for Safety and Effectiveness
Other tips for taking iron are as follows:
- For best absorption, iron should be taken between meals. Iron may cause stomach and intestinal disturbances, however. Low doses of ferrous sulfate can be taken with food and are still absorbed but with fewer side effects.
- Drink a full 8 ounces of fluid with an iron pill. Taking orange juice with an iron pill can help increase iron absorption. (Some providers also recommend taking a vitamin C supplement with the iron pill.)
- If constipation becomes a problem, take a stool softener such as docusate sodium (Colace).
- Certain medications, including antacids, can reduce iron absorption. Iron tablets may also reduce the effectiveness of other drugs, including the antibiotics tetracycline, penicillin, and ciprofloxacin and the Parkinson disease drugs methyldopa, levodopa, and carbidopa. At least 2 hours should elapse between doses of these drugs and iron supplements.
- Avoid taking milk, caffeine, antacids, or calcium supplements at the same time as an iron pill because they can interfere with iron absorption.
- Tablets should be kept in a cool place. (Bathroom medicine cabinets may be too warm and humid, which may cause the pills to disintegrate.)
An increase in hemoglobin of 1 g/dL after one month of iron therapy confirms the diagnosis and indicates that the treatment is working. However, iron therapy should be continued for 3 months after the anemia is corrected to replenish the body's iron stores in the bone marrow.
In some cases, supplemental iron is administered intravenously. Intravenous iron is used to treat iron-deficiency anemia. It may be recommended for people who:
- Are unable to absorb oral iron or have anemia that has continued to worsen after taking oral iron
- Have very severe iron deficiency or blood loss
- Have serious gastrointestinal disorders, such as severe inflammatory bowel disease, or have had stomach or intestine surgery and cannot take iron therapy by mouth
- Are receiving supplemental erythropoietin therapy
Intravenous iron may be given in the form of iron dextran (Dexferrum, INFeD), iron sucrose (Venofer), ferric gluconate (Ferrlecit), ferumoxytol (Feraheme), or ferric carboxymaltose (Injectafer). Your provider may refer you to a hematologist (a doctor who specializes in blood disorders) to oversee this treatment.
Some intravenous iron can cause an allergic reaction. It might be important to administer a test dose before you receive your first infusion. The risk for allergic reactions is higher with iron dextran than with other forms of intravenous iron. Intravenous iron should never be given at the same time as oral iron supplements.
Transfusions are used to replace blood loss due to injuries and during certain surgeries. They are also commonly used to treat people who have thalassemia, sickle cell disease, myelodysplastic syndromes, or other severe types of anemia. In certain cases, blood transfusions may be used to treat severe anemia associated with heart disease.
Some people require frequent blood transfusions, which can cause a side effect of iron overload. If left untreated, iron overload can lead to liver and heart damage.
Iron chelation therapy is used to remove the excess iron caused by blood transfusions. It uses a drug that binds to the iron in the blood. The bound form of excess iron is then removed from the body by the kidneys. Deferasirox (Jadenu) is an example of medicine for iron overload due to blood transfusions.
Erythropoietin is the hormone that acts in the bone marrow to increase the production of red blood cells. It has been genetically engineered as recombinant human erythropoietin (rHuEPO) and is available as epoetin alfa (Epogen, Procrit, Retacrit). Novel erythropoiesis stimulating protein (NESP), also called darbepoetin alfa (Aranesp), lasts longer in the blood than epoetin alfa and requires fewer injections. These medications are also called "erythropoiesis-stimulating drugs."
Levels of erythropoietin are reduced in anemia of chronic disease. Injections of synthetic erythropoietin can help increase the number of red blood cells in order to avoid receiving blood transfusions.
Synthetic erythropoietin can cause serious side effects, including blood clots, and is approved only for treating select people with anemia related to certain conditions such as anemia caused by chronic kidney disease, cancer chemotherapy, and HIV/AIDS treatment with zidovudine.
Erythropoiesis-Stimulating Drugs and Cancer
Erythropoietin may be used to treat anemia caused by chemotherapy. Erythropoietin treatment does not help prolong survival, but can improve quality of life during cancer treatment by improving anemia.
However, these drugs may shorten lifespan and may cause some tumors to grow faster. The American Society of Clinical Oncology and the American Society of Hematology recommend starting erythropoietin for chemotherapy-associated anemia only if the hemoglobin level is less than 10 g/dL. These drugs should not be used when the goal of the chemotherapy is to cure the cancer.
Erythropoiesis-Stimulating Drugs and Chronic Kidney Disease
For people with chronic kidney disease or kidney failure, the FDA currently recommends that erythropoiesis-stimulating drugs be considered when hemoglobin levels are lower than 10 g/dL.
Contact your provider if you have any of the following symptoms while being treated with an erythropoiesis-stimulating drug:
- Pain or swelling in the legs
- Worsening in shortness of breath
- Increases in blood pressure (be sure to regularly monitor your blood pressure)
- Dizziness or loss of consciousness
- Extreme fatigue
- Blood clots in hemodialysis vascular access ports
Guidelines for Treating Anemia in People with Heart Problems
The American College of Physicians (ACP) has clinical practice guidelines for treating anemia in people with heart failure, coronary artery disease, or heart attack. According to the ACP, current evidence suggests as best practice for people with heart conditions:
- Blood transfusions may be effective for severe anemia, but are not helpful for milder anemia.
- Erythropoiesis-stimulating drugs should not be used to treat mild-to-moderate anemia; these drugs can increase the risk for blood clots and other problems.
- There is insufficient evidence to determine if intravenous iron is beneficial for people with heart conditions who have iron-deficiency anemia.
Vitamin Replacement for Megaloblastic Anemia
If folate deficiency is responsible, treatment usually involves taking a daily oral folic acid supplement until laboratory tests show levels have returned to normal, as well as increasing intake of foods rich in folate. When vitamin B12 deficiency is responsible, vitamin B12 supplementation may be administered in tablets, injections of cyanocobalamin (Cobal 1000) or hydroxocobalamin (Cyanokit), or as a nasal spray. Often both folate and vitamin B12 are needed to treat megaloblastic anemia.