Injectable Iron “Injectafer” Linked to Increased Severe Hypophosphatemia

Infectafer is one of two major forms of an injectable iron complex used to treat iron deficiency anemia (IDA) in adult patients who cannot take iron supplements or who have had a poor response to them.

Injectafer has gained in popularity in recent years over iron isomaltoside (IIM)as a rapid treatment for IDA, but clinical studies have concluded that the drug may have serious side effects for some people and that it carries a much greater risk of causing HPP than its competitor, IIM. These side effects include severe hypophosphatemia (HPP), a dangerously low level of phosphorus in the blood that can cause life-threatening complications.

Treatment for Adult Iron Deficiency Anemia

Iron deficiency anemia is a condition in which the body stops producing enough hemoglobin because of a shortage of the essential mineral iron. The body uses iron to produce hemoglobin, a protein in red blood cells that is responsible for carrying oxygen around the body. If a person suffers from a deficiency of iron, the production of hemoglobin suffers. Soon there is not enough oxygen in the body to meet daily demands, and organs may not function as they should.

Symptoms of iron deficiency anemia include:

• excessive fatigue
• pale skin
• muscle weakness
• cold hands and feet
• shortness of breath
• lightheadedness
• unusual cravings for things like dirt and ice.

The condition is often treated with oral iron supplements, but recovery takes time—usually three months or more before iron levels are restored to normal.

Some patients don’t respond well to treatment with oral supplements, however, either because they can’t absorb the iron well or because they can’t tolerate it, often as a result of digestive problems. These patients are sometimes treated with an injectable iron treatment, like Injectafer which is a ferric carboxymaltose (FCM) iron or iron isomaltoside (IIM) such as Monofer, which can alleviate symptoms quickly.

Studies Show Injectafer Increases Risk of Severe Hypophosphatemia

HPP is a condition in which blood levels of phosphate drop to such a low level that a person begins to experience symptoms and potential complications. Severe HPP is the most extreme and dangerous type of HPP. Severe HPP can result in alarming health problems when phosphate levels drop and remain untreated. Injuries that may result include seizures, muscle wasting, respiratory failure, acute hemolytic anemia (in which red blood cells are destroyed), arrhythmias, bone pain and fractures, confusion, delirium, coma, and even death.

A number of clinical studies have shown that Injectafer increases the risk of HPP and severe HPP substantially more than the alternative, IIM iron injections. In 2016, for example, researchers in Austria reported in a PLoS One research article that the risk of HPP was substantially greater after an injection of ferric carboxymaltose (FCM), the type of iron used in Injectafer, than following treatment using iron isomaltoside (IIM), an alternative intravenous iron supplement used in Monofer. More specifically, 45.5% of patients injected with FCM developed HHP, and 32.7% developed severe HPP. In sharp contrast, none of the patients who received an IIM injection developed severe HPP.

Other studies have shown similar results, but American Regent, Inc., a subsidiary of Luitpold Pharmaceuticals, Inc. and the manufacturer of Injectafer, has failed to adequately warn patients and their doctors about the serious risk. To date, American Regent of Shirley, New York has only revealed to the public that Injectafer may result in mild side effects like headaches, nausea, and “low levels of phosphorus in the blood.”

American Regent and its related companies including Daiichi Sankyo, Inc. of Basking Ridge, New Jersey and Luitpold Pharmaceuticals, Inc. of Norristown, Pennsylvania, have failed to warn patients and doctors of the risk of severe HPP.