Common Mistakes in Iron Chelation Therapy

Submitted by sankalp on Tue, 07/15/2014 - 13:24

Iron chelation is an important and very costly part of thalassemia management. Over last 3 years we have been monitoring and helping make better the chelation therapy for children with thalassemia. We share here the common mistakes which often go unnoticed.

Dosage

We came across several children who believed that they were on proper chelation for quite some time. However, often we find that children are taking sub-optimal dosage. The following doses are recommended for thalassemia children:

  • Defariserox: 20-30 mg/kg/day going up-to 40mg/kg/day in case of children who have heavy iron overload and which is not coming under control with dose up-to 30mg/kg/day.
  • Deferiprone: 75-150 mg/kg/day.

At the initiation the chelator dose should be started at the lower dose because there may be problems related to tolerance of the medicine.

Review of Chelation Dose

Several children continue to be on the same dose for chelator for long periods of time without adequate attention being given to review of dosage. Quarterly ferritin test must be done to see if the chelator is helping control serum iron level. If the iron level is increasing the dose should be increased. If the child is put on aggressive chelation dose and the ferritin falls into the acceptable range, the dosage should be decreased.

Some children need to be started on lowed dose of medicine because they don't tolerate higher doses well. For such children the dose should be gradually increased.

Complications associated with Chelation

Chelation therapy is not without it's own side effects. Chelation therapy is known to influence the mineral balance in the body, affect the kidney and the liver functions and cause neutropenia beside several other complications. While some of these complications are noticeable by the child/family other need proper periodic haematological and biochemical tests to identify. It is necessary that quarterly investigations be done to keep a check on the complications that may arise out of chelation therapy.

The more important aspect is the knee jerking response families tend to have in the event of complications associated with chelation. It is a known fact that some complication may occur. When this happens, there are better management strategies prescribed in literature than simply reject the chelator for therapy. There are mechanisms by which tolerance can be improved.

Sometimes it may be required to withdraw the chelator for a while. However, we have seen events when children stopped taking chelator altogether because they suspected the chelator to be the cause of complications rather than work their way through managing chelation therapy with improved tolerance.

Rejection of chelation therapy by children

Sometimes it has been seen that certain children claim that their child does not want to take a particular chelator at all. The problem becomes more intense in younger kids. Since chelator is to be taken in suspension, the medium in which it is dissolved may play a major role in enabling acceptance of a chelator to the child. It is advisable to try different juices, flavoured glucose etc. to make the chelator more acceptable to the kids.

Proper administration

We have realised that several parents are not adequately informed about how the chelator should be taken. Patients are often found to make the suspension of the chelator in metal glasses stirring it with metal spoons. They are found to take chelator at different times in the day. These are all small mistakes which reduce the efficacy of the drug. The guidelines from the supplier should be strictly followed.

In-adequate and improper information about available options for chelation

With several manufacturers offering their products in the market for iron chelation therapy it should be only justified that unbiased information about available options be made available to the patients. Commercial interests of particular organisations or individuals must not influence access to and accuracy of information available to the patients about the alternatives. When comparing offerings from different sources nothing but the published scientific outcome should hold ground.

Ferritin is not enough

It must be noted that serum ferritin may not be the best marker of the iron overload in the body especially when it comes to iron absorption in the organs. T2 MRI is the gold standard. However, it must be noted that not all T2 MRI operators are trained to be able to accurately access the iron overload. Annual MRI helps maintain accurate picture of the degree of iron overload.

Having said this, the fact that MRI is expensive, and access to it is difficult, MRI could be used to improve the picture of iron overload as shown by serum ferritin rather than reject the later altogether. In a situation like ours where most kids are badly under chelated, it should make no difference whether MRI is done or not if adequate chelation is not organised for regularly. Only when the logistical and economic difficulty to organise for chelator is taken care of, the option to fine tune and make more accurate the therapy comes into picture.

Liver iron concentration (LIC) is also more accurate than ferritin but it still continued to be less accurate than MRI.

Adherence

The final and most important aspect is to monitor the adherence of the child to the dose prescribed by the doctors. It has been seen that for financial reasons the parents make independent decisions to reduce the dose of chelation being offered to the child. There are issues of non-compliance associated with the medicines especially when the dose has to be taken twice or thrice daily. The centers must track all the purchases of chelators so as to maintain a clear view of adherence to the therapy.