Yet Another Injectafer Study Links Iron Infusions to Severely Low Phosphorus Levels

Published on August 12, 2019 by Sandy Liebhard

A new study appears to confirm previous research linking Injectafer to severe hypophosphatemia, a potentially life-threatening condition marked by dangerously low levels of phosphorus in the blood.

How the Injectafer Study Was Conducted

Injectafer (ferric carboxymaltose) is an intravenous medication for adults with iron deficiency anemia who can’t tolerate or otherwise use oral iron supplements. Because Injectafer is administered directly into the blood stream, it works faster and eliminates issues associated with malabsorption and gastrointestinal toxicity. But while any iron infusion drug can cause hypophosphatemia, a growing body of research that Injectafer is more likely to cause severely low phosphorous levels.

The latest Injectafer study, which appeared this month in Alimentary Pharmacology & Therapeutics, involved 130 patients with inflammatory bowel disease, all of whom suffered from iron deficiency/iron deficiency anemia. Fifty-two where treated with Injectafer, while 64 received another iron infusion drug called Monofer (isomaltoside).

Blood and fecal samples were obtained from each patient prior to their first infusion, and again at 2-weeks and 6-weeks post-treatment.

What the Study Found

According to the study authors, patients who received Injectafer infusions had a significantly higher incidence of moderate‐to‐severe hypophosphatemia compared with Monofer at week 2 (56.9% vs 5.7%, P < 0.001) and a higher incidence at week 6 (13.7% vs 1.9%, P = 0.054). The overall incidence of hypophosphatemia was also significantly higher with Injectafer compared to Monofer treatment at weeks 2 (72.5% vs 11.3%, P < 0.001) and 6 (21.6% vs 3.7%, P = 0.013).

“In IBD patients with iron deficiency/iron deficiency anaemia, ferric carboxymaltose was associated with higher incidence, severity and persistence of hypophosphatemia compared with iron isomaltoside,” they concluded. “The presence of moderate‐to‐severe hypophosphatemia beyond 6 weeks is a clinical concern that requires further investigation.”

What is Hypophosphatemia?

Individuals who suffer from persistent, severe hypophosphatemia (phosphorus levels below 1mg/dL) may experience:

• Muscle weakness
• Fatigue
• Bone pain
• Bone fractures
• Loss of appetite
• Irritability
• Numbness, tingling, or tremors
• Confusion

If allowed to remain untreated, this dangerous condition can also result in respiratory failure, muscle weakness, cardiac arrest, seizures, coma, and even death.

Injectafer and Hypophosphatemia: The Evidence

Unfortunately, this is not the first Injectafer study to link the iron infusions to dangerously low levels of phosphorus. In 2016,  Austrian researchers reported that hypophosphatemia had occurred in 45% of those treated with Injectafer, while 32% developed severely low phosphorous levels.

Just last December, findings  published in the Journal of Clinical Investigation suggested over half of those treated with Injectafer will develop severe hypophosphatemia.

A growing number of Injectafer lawsuits that blame the iron infusions for causing severe, persistent hypophosphatemia have since been filed in courts around the United States.