Infed is a brand name for iron dextran, an intravenous, or IV form, of supplemental iron. Iron is required to produce hemoglobin, the oxygen-carrying protein in red blood cells. Depletion of the body’s iron stores results in iron deficiency anemia, which is diagnosed by a low level of hemoglobin in the blood. The goals of treatment are to correct anemia and replace storage iron. Although oral iron tablets are the most commonly prescribed therapy, IV iron is often necessary.
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Infed is recommended when oral iron supplements are either not tolerated or are ineffective. Iron pills frequently have gastrointestinal side effects that are sometimes severe enough to interrupt treatment. Intravenous iron is also used when oral iron cannot be absorbed due to intestinal surgery or disease. It is the optimal therapy for severe anemia, and when continued iron losses from gastrointestinal bleeding exceed iron absorption by the small intestine.
Infed is infused slowly through a tube directly into a vein, usually in the arm. The total dose of Infed required to correct anemia and replace iron stores is often given as a series of infusions. For example, a typical total dose of 1000 mg may be divided into five weekly infusions of 200 milligrams.
Alternatively, the total dose of Infed can be given as a single infusion over four to six hours. Injection into a muscle is not recommended because it is painful and iron is poorly absorbed.
The number of newly produced red blood cells, called reticulocytes, increases four or five days after an Infed infusion. The hemoglobin level rises within seven to 14 days, reaching a normal value by six to eight weeks. It increases more rapidly after a single total dose infusion than when the same dose is divided into multiple infusions. Approximately 50 percent of the infused iron is incorporated into hemoglobin within three to four weeks. The rest is stored in a protein called ferritin, available for future use. Symptoms of anemia such as fatigue and weakness often improve during the first week, even before correction of anemia.
Infed reverses iron deficiency anemia more rapidly than oral iron supplements. Intravenous iron is a more reliable treatment since the full dose is delivered directly to the bone marrow, bypassing the need for intestinal absorption.
Infed can be given as a single total dose infusion when severe anemia requires urgent treatment, which often avoids the need for a blood transfusion. For some people, an Infed infusion is more convenient than a daily iron supplement, since it shortens the duration of therapy.
Side effects from Infed may be immediate or delayed, and most are mild and transient. A rapid infusion causes pain at the injection site, flushing and a metallic taste. Slowing the infusion rate relieves these symptoms. Other immediate side effects include nausea, headache, rash, chills, a rapid heart rate and chest tightness.
Severe life-threatening reactions occur in less than 1 percent of people. The symptoms include chest and back pain, difficulty breathing, wheezing, throat swelling and fainting. This rare allergic reaction develops within a few minutes after starting the infusion and may be fatal. According to a study in "Nephrology Dialysis Transplantation" in 2006, approximately three life-threatening reactions and one death occur per million doses of Infed infused.
Muscle and joint pain, backache, fever, headache and nausea or vomiting may develop 24 to 48 hours after an Infed infusion. This delayed reaction is more common after a single total dose infusion, and usually resolves within three to seven days. Repeated infusions of Infed can cause a brown discoloration of the skin that disappears after several months.
Because of the risk of a serious allergic reaction, an initial test dose is required when Infed is given for the first time. A small portion of the dose is infused slowly. If no reaction occurs over the next hour, the remaining dose is given. Infed must be administered in a hospital or other medical facility by health care providers trained to handle serious reactions. Medications are often given before the infusion to prevent side effects.