A prescription treatment for anemia has been around for years, but recent lawsuits claim it can cause serious and potentially deadly side effects.

Two lawsuits filed in Philadelphia by Teresa J. Edwards and Barbara Kessler earlier this year claim Injectafer (ferric carboxymaltose injection), a drug used to treat iron deficiency anemia in adults, led plaintiffs to develop abnormally low levels of phosphorus — a condition known as hypophosphatemia, or HPP.

Hypophosphatemia can occur after severe burns, alcoholism, diabetic ketoacidosis, poor diet, sepsis and other medical conditions.

Mild HPP doesn’t typically have symptoms, but severe cases can lead to symptoms including: muscle weakening, bone and joint pain, seizures, breathing problems, heart problems and even death.

Edwards received 10 infusions over several months in 2018, 2019 and 2020. She suffered symptoms of HPP including: Severe muscle fatigue and weakness, severe fatigue, and severe and extended pain.

Kessler received several infusions of Injectafer from 2016 to 2019. She suffered from bone pain, severe fatigue and weakness, and shortness of breath and was later diagnosed with HPP.

Despite knowing that the drug could cause severe HPP, Injectafer lawsuits allege drug makers failed to include adequate warnings for physicians and the public.

Labels Don’t Adequately Warn of Risk

Lawsuits allege the U.S. Food and Drug Administration denied Luitpold’s new drug application for Injectafer several times before it finally approved the drug in 2013.

The FDA found clinical safety issues including an “unacceptable risk for death, serious adverse reactions, and clinically important hypophosphatemia,” court documents say.

Despite these clinical findings, Luitpold released Injectafer in the US without adequate warnings, according to lawsuits. The July 2013 label at the drug’s launch “did not warn of severe hypophosphatemia and downplayed the risk, severity, and prevalence of low phosphorus levels.”

It wasn’t until February 2020 that the label warned of hypophosphatemia, but lawsuits say it isn’t enough and the risk is still downplayed.

Studies Link Injectafer to Hypophosphatemia

Originally approved in 2013, Injectafer is the only treatment for iron deficiency anemia made with ferric carboxymaltose (FCM).

In several studies, researchers found hypophosphatemia occurred more often in anemia patients treated with FCM versus other treatments.

For example, in one 2020 study published in BMC Medicine, researchers found 75 percent of the women treated with FCM in the study suffered from hypophosphatemia compared to only eight percent of those treated with ferric derisomaltose.

These two recent lawsuits join a growing number of cases filed over the last several months, and lawyers expect more lawsuits to be filed.