Thalassaemia drug. Bottle of the chelating agent Desferal (deferoxamine). A chelating agent removes heavy metals. In this case it removes excess iron from the blood. This is a common condition in patients who have to undergo regular blood transfusions, for example patients with thalassaemia. Thalassaemia is an inherited condition where the red blood cells are fragile and easily damaged. For chronic conditions like thalassaemia, the drug is infused gradually over several hours daily, by subcutaneous injection. Desferal can also be used to treat iron and aluminium poisoning. The use of Desferal is preferred to other chelating agents, due to fewer side-effects.