Injectafer Linked to Hypophosphatemia
Medical research suggests that some patients receiving an iron injection treatment may develop hypophosphatemia, but a growing body of evidence shows that severe hypophosphatemia occurs more frequently in patients who receive Injectafer compared to other iron injection treatments. In one study published in 2018, researchers compared Injectafer to Feraheme, another IV injection indicated for the treatment of iron deficiency anemia. According to their findings, more than half of the patients treated with Injectafer developed severe hypophosphatemia and 10% developed extreme hypophosphatemia. Comparatively, less than 1% of those treated with Feraheme (ferumoxytol) developed severe hypophosphatemia and none developed extreme hypophosphatemia.
Another study published in the Journal of the American Medical Association in February 2020 found that 75% of patients who received Injectafer developed hypophosphatemia, compared to only 7.9% of patients given another iron infusion drug called Monoferric (ferric derisomaltose). Severe hypophosphatemia was reported in 11.3% of patients treated with Infectafer and in zero patients treated with Monoferric. The same month the JAMA study was released, the Injectafer label was updated to include the potential risk of symptomatic hypophosphatemia tied to Injectafer treatment. The Injectafer label warning now reads:
Symptomatic hypophosphatemia requiring clinical intervention has been reported in patients at risk of low serum phosphate in the postmarketing setting. These cases have occurred mostly after repeated exposure to Injectafer in patients with no reported history of renal impairment. Possible risk factors for hypophosphatemia include a history of gastrointestinal disorders associated with malabsorption of fat-soluble vitamins or phosphate, concurrent or prior use of medications that affect proximal renal tubular function, hyperparathyroidism, vitamin D deficiency and malnutrition. In most cases, hypophosphatemia resolved within three months.