> ## Content Index
> Fetch the complete content index at: https://www.fdaweb.com/llms.txt
> Use this file to discover other available public pages before exploring further.

# Boxed Warning for Injectafer on Low Phosphate Levels
- URL: https://www.fdaweb.com/boxed-warning-for-injectafer-on-low-phosphate-levels/
- Published: 2026-09-02T12:00:00.000Z
- Updated: 2026-09-14T12:05:19.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5161723

FDA has ordered a [Boxed Warning](https://www.fda.gov/drugs/drug-safety-communications/fda-adds-boxed-warning-labeling-ferric-carboxymaltose-injection-injectafer-describe-risk-low?ref=fdaweb.com) for American Regent’s Injectafer (ferric carboxymaltose injection) over the risk of symptomatic hypophosphatemia, a potentially serious condition in which phosphate levels in the blood become abnormally low.

The warning recommends monitoring blood phosphate levels in patients considered at risk for the condition, as well as in any patient who receives a repeat course of Injectafer within three months of a previous course.

Hypophosphatemia can cause symptoms ranging from muscle weakness or pain and fatigue to tremors, confusion and, in severe cases, seizures and abnormal heart rhythms. Prolonged, severe phosphate deficiency can cause osteomalacia, or softening of the bones, and may lead to fractures.

FDA says it decided to strengthen the drug’s warning after a 2026 review of reports involving ferric carboxymaltose injection. The agency examined multiple sources of safety data, including its adverse-event reporting system, published medical literature and its Sentinel System.

That assessment found that cases of symptomatic hypophosphatemia continue to be reported among patients receiving ferric carboxymaltose, despite earlier changes to the drug’s labeling intended to address the risk. FDA first determined in 2019 that ferric carboxymaltose injection could cause serious symptomatic hypophosphatemia. In February 2020, the agency approved labeling changes that included a warning about the condition.