FDA Adds Boxed Warning to Labeling for Ferric Carboxymaltose Injection (Injectafer) to Describe Risk of Low Phosphate Levels FDA Drug Safety Communication – September 1, 2026

https://www.fda.gov/drugs/drug-safety-communications/fda-adds-boxed-warning-labeling-ferric-carboxymaltose-injection-injectafer-describe-risk-low?utm_medium=email&utm_source=govdelivery FDA Adds Boxed Warning to Labeling for Ferric Carboxymaltose Injection (Injectafer) to Describe Risk of Low Phosphate Levels The Food and Drug Administration has approved revisions to the labeling for ferric carboxymaltose injection (currently marketed as Injectafer) that adds a boxed warning, the agency’s most prominent safety warning. This boxed warning describes the risk for symptomatic hypophosphatemia (low levels of phosphate in the blood) associated with ferric carboxymaltose injection and recommends phosphate monitoring in patients at risk of hypophosphatemia and in any patient who receives a repeat course of therapy within three months of the prior course. Clinical manifestations depend on the severity and duration of hypophosphatemia. Symptoms may include muscle weakness or pain, fatigue, tremors, confusion, seizures, and cardiac arrhythmias. Chronic severe hypophosphatemia may lead to osteomalacia (bone softening) and bone fractures. FDA has previously approved other labeling updates for Injectafer that describe this risk. In 2019, FDA determined that ferric carboxymaltose injection can cause serious symptomatic hypophosphatemia. As a result, in February 2020, FDA approved labeling revisions that, along with other changes, added a warning about this risk. In 2023, the warning was revised to include recommendations for serum phosphate level monitoring in patients at risk for hypophosphatemia and in any patient who receives a repeat course of treatment within three months. The revised warning also included osteomalacia and fractures as potential long-term complications and added inflammatory bowel disease as a possible risk factor for hypophosphatemia. In 2025, the warning was further revised to include additional risk factors for hypophosphatemia. In 2026, FDA conducted an assessment of hypophosphatemia in association with ferric carboxymaltose injection using multiple data sources, including the FDA Adverse Event Reporting System (FAERS) database (which has been incorporated into the FDA Adverse Event Monitoring System [AEMS] database), literature reports, and FDA’s Sentinel System. FDA found that symptomatic hypophosphatemia continues to be reported with ferric carboxymaltose injection and serum phosphate testing levels are low despite labeling changes in February 2020 and May 2023.