Iron Preparations

Iron Deficiency​​​​​​​

There are two types of iron preparations that support the treatment of iron deficiency anemia. Ferrous sulfate is an oral form of iron. Iron dextran is an intramuscular and intravenous form of iron.

Give iron preparations to treat iron-deficiency anemia secondary to blood loss or an inadequate intake of iron-containing foods. Also, give iron preparations to prevent iron-deficiency anemia in clients at risk, such as infants, children, women who are pregnant, or clients experiencing acute or ongoing blood loss. Occult or microscopic bleeding from the gastrointestinal tract is one reason for ongoing blood loss. 

Prototype and Other Medications

Classification: Antianemics

Ferrous sulfate is the prototype for iron preparations. Iron dextran is the injectable form of iron and is made up of ferric hydroxide and dextran. Other related iron preparations include ferrous gluconate and ferrous fumarate. ​​​​​​​

Expected Pharmacologic Action

While red blood cells, or erythrocytes, are developing, they synthesize hemoglobin in the cell. Hemoglobin is a necessary component for erythrocytes to carry oxygen from the lungs to the entire body. Hemoglobin is made up of four heme groups and one globin group. The heme part contains iron. The globin part is a protein that binds the heme groups together, making a molecule of hemoglobin. Hemoglobin cannot carry oxygen without iron. Clients who are iron deficient experience weakness, fatigue, and shortness of breath. Iron preparations are given to replace iron deficiency and restore the body’s ability to carry oxygen. 

Adverse Drug Reactions

Gastrointestinal side effects are the most common with iron preparations. These include nausea, epigastric pain, and diarrhea or constipation. Iron dextran, the parenteral form, can cause a metallic taste in the mouth. Iron dextran has also been associated with seizures and/or anaphylactic reactions ending in death. Take proper precautions with the liquid form of iron to avoid the risk of stained teeth. Fatal iron toxicity can also occur if clients consume too much. This happens most frequently in children who overdose on iron-containing vitamins because they mistake them for candy. Because children’s vitamins are available in gummy and chewable forms, this is a real danger. To prevent iron poisoning in children, iron should be kept in a childproof container, out of reach from young children.

Safety Alert

Iron toxicity occurs secondary to an acute accidental or intentional overdose. Iron poisoning in children is one of the leading causes of fatalities related to poisoning. As mentioned above, all iron-containing products should be kept in childproof containers and out of reach of children. Early manifestations of iron toxicity include stomach pain, nausea, vomiting (may contain blood), diarrhea, and shock. If treatment is not sought, clients may die because of multiple organ failure or gradually improve with varying degrees of permanent damage to the gastrointestinal tract and other organs. Gastric lavage with sodium bicarbonate treats acute poisoning in an effort to remove as much iron that is still in the stomach as possible. Bowel irrigations may also be done to prevent additional absorption of iron from the intestinal tract. A chelating agent, such as deferoxamine, binds with iron in the blood and promotes its excretion. 

Interventions

Give an iron preparation with food if the client has severe gastrointestinal manifestations. While the ideal way to take an iron preparation is on an empty stomach because taking it with food reduces absorption, many clients cannot tolerate taking iron in this manner because of gastric irritation. If clients aren’t tolerating the form and dose of iron prescribed, consider recommending a lower dosage. Monitor bowel patterns because diarrhea or constipation is a common side effect. Also, monitor for staining of the teeth with iron dextran, the liquid form of iron, and give clients hard candy to suck on or gum to chew for the metallic taste it leaves in the mouth. Ensure dosage for children is according to specific iron preparation. Follow the manufacturer’s recommendations regarding appropriate dosages for children. Monitor all clients for toxicity. Manifestations of toxicity include severe gastrointestinal findings and shock, which, if not treated, can evolve into acidosis and liver and heart failure. If a client is diagnosed with iron toxicity, expect to parenterally administer a chelating agent, such as deferoxamine. A chelating agent binds with a particular metal, creating an inactive complex that is excreted from the body. 

Administration

When administering the injectable form, give a test dose of 25 mg first to determine if the client is sensitive to iron. Have epinephrine available in case of a hypersensitivity reaction. If the client tolerates the test dose without adverse effects, follow with the prescribed dose 1 hr later. Do not give the prescribed dose sooner because sensitivity reactions can occur up to 1 hr after injection. Administer the intramuscular form with a syringe that has a 2- to 3-inch-long needle and use a Z-track injection technique to avoid staining the skin if the iron leaks out of the insertion site. Give prescribed intravenous doses no faster than 50 mg/min or dilute the dose for intermittent infusion in 200 to 1,000 mL of 0.9% sodium chloride and infuse over 1 to 6 hr, depending upon the concentration. Monitor blood pressure for hypotension. Be sure that clients are not also taking an oral form of iron when receiving iron dextran due to the risk of toxicity. When administering a liquid form of iron, first dilute it in another compatible liquid and then give it through a straw. Have clients rinse their mouths with plain water and suck on hard candy or chew gum to get rid of the bad taste and prevent tooth staining.

Spread oral doses of ferrous sulfate evenly over the waking hours to maximize the production of red blood cells (RBCs). For best absorption, give the medication on an empty stomach; however, give the medication with food if this enhances compliance. Check with the provider to see if an increase in dose is needed because food decreases the medication’s absorption. Make sure clients do not crush or chew the sustained-release forms due to the potential for stained teeth. Discontinue the medication when anemia resolves, as evidenced by hemoglobin (Hgb), hematocrit (Hct), and reticulocyte (RBC) counts returning to the expected reference range. This usually takes 1 to 2 months of therapy. However, place women who are pregnant on iron therapy for several months. If clients have difficulty tolerating iron or have just completed their prescribed length of therapy, recommend foods high in iron such as liver, egg yolks, muscle meats, whole grain cereals, and leafy green vegetables. Clients can avoid future iron therapy by eating such foods. Similar to calcium, the amount of iron ingested does not equal the amount of elemental iron made available to the body. Be sure the dose of the selected preparation is adequate in regard to providing the needed amount of elemental iron.​​​​​​​  

Client Instructions

During client instruction regarding iron preparations such as ferrous sulfate, encourage clients to take the medication on an empty stomach first. If gastrointestinal effects are too disturbing, tell the client to take it with food to minimize discomfort but to understand that food reduces absorption. Many gastrointestinal effects diminish as therapy continues; however, tell clients to report continued gastric irritation. Warn clients that stools may become dark green or black, which is a harmless discoloration that occurs secondary to the iron. As for constipation, instruct clients to increase exercise as well as fluid and fiber intake. Tell clients who are taking a liquid form of iron to dilute it with water and drink it through a straw. If the taste is unpalatable, check the label about diluting the iron in another liquid. For example, some liquid forms are compatible with milk and juice while others are not. Recommend clients suck on hard candy or chew gum to relieve a metallic taste in the mouth. When giving the liquid form to infants, use a dropper placed towards the back of the tongue. Instruct clients to rinse their mouths after taking it to prevent stained teeth and get rid of the bad taste. Instruct caregivers of children to store iron preparations in childproof containers, in locked cabinets, out of children’s reach.

Contraindications and Precautions

Do not give iron preparations to clients who have anemias that are not caused by a lack of iron in the body, such as hemolytic anemia or hemochromatosis. Caution should be used in clients with liver disease, alcohol use disorder, or severe renal impairment. Oral iron preparations are contraindicated for clients who have gastrointestinal disorders, such as peptic ulcer disease, ulcerative colitis, and regional enteritis. 

Interactions

Antacids reduce the absorption of oral iron. Vitamin C increases the absorption but also increases the risk of gastrointestinal effects. When administered concurrently with tetracyclines, fluoroquinolones, bisphosphonates, and penicillamine, iron supplements will decrease their absorption, so they should be avoided. Concurrent use with ACE inhibitors may increase the risk of anaphylactic reaction with iron dextran.