Iron Overload and Chelation Therapy (2)

Why are accurate measurements of iron important for transfused patients?
Dr. Nancy Olivieri of Toronto and Dr. Gary Brittenham of Cleveland studied several patients and found that after a specific threshold - 7 mg of hepatic (liver) iron per gram dry weight - a patient will experience increased risk of illness and death. Those with iron levels over 15 mg/g dry weight experience substantial risk for death. Conversely, levels under 3 mg/g dry weight, while considered normal for non-transfused people, should be avoided for transfused patients because of the associated risks of Desferal toxicity. These include growth problems, pulmonary toxicity, kidney dysfunction, spinal and bony changes (crucial for the growing child), auditory problems (tinitus or ringing in the ears), and ocular abnormalities. Thus it is important for thal patients to keep their body iron levels between a specific range of 3 - 7 mg/g dry weight for optimal health. Dr. Olivieri recommends annual liver biopsies at the same time every year. For patients with steady levels, the time between biopsies can increase 1 1/2 to 2 years.

Currently, the best way to rid the body of extra iron is through daily infusions of desferrioxamine or Desferal. Desferal actively binds iron that it encounters in the body and excretes it in urine and stool. A study conducted by Sir David Weatherall et al showed that optimal iron chelation occurred when Desferal was infused 24 hours a day every day, while 12 hours of infusion was 80% as effective as a 24-hour infusion. For most patients' lifestyles, though, this amount of therapy is inconvenient. Many people do not allot twelve hours every evening for Desferal therapy. However, the longer a patient uses Desferal, the better for their health. If, for example, a person returns home at two in the morning, he should not forego the night because of reduced treatment time. Nor should he double the amount of Desferal, since concentrated doses are irritating to the body. Dr. Olivieri suggests patients think about maximizing the amount of Desferal time over a week rather than day to day. This way, hours clocked in, no matter when or where, work toward chelating iron. Read more about Desferal in the next section. <next>

<page 1> <page 2> <page 3> <page 4>

To learn more about Iron Overload, including treatment recommendations and systems effected by iron-overload, please see pages 7-11 of our Standard of Care Guidelines.