Ferumoxytol, known as Feraheme or Rienso was approved by the FDA in 2009, is an intravenous drug formulation with neutral pH for treatment of anemia. It is prescribed for adult patients with evidence of iron overload. Clinical studies have shown that an intravenous injection of 510 mg of ferumoxytol is well tolerated. According to the AMAG label for Feraheme, 0.2 and 1.9% of patients who received it experienced hypersensitivity reactions and hypotension respectively. In clinical trials, some serious side effects of Feraheme were nausea, diarrhea, hypotension, constipation, dizziness and peripheral edema. Feraheme, an iron replacement product, is a non-stoichiometric magnetite (superparamagnetic iron oxide) coated with polyglucose sorbitol carboxymethylether. The overall colloidal particle size is 17-31 nm in diameter.