Desferal usage as per Body weight

Hello,

This is a question regarding how much Desferal should be used as per body weight, my daugther is 32lbs and she is using one vile six nights a week, we were told soon she will be on two viles when her body weight increase. Any suggestion how much body weight she has to be in order to use two viles.

Thanks and regards

Taken from the Norvatis web site: http://www.novartis.com.au

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DOSAGE AND ADMINISTRATION

The presence of iron overload, preferably quantified, should be established before initiating
therapy with Desferal.

Treatment for Chronic Iron Overload

Commencement of therapy:

The main aim of chelation therapy in iron overload in young patients is to achieve an iron balance and to prevent haemosiderosis, while in older patients a negative iron balance is desirable in order to reduce slowly the increased iron stores and to prevent the toxic effects of iron. It is recommended that therapy with Desferal be started after the first 10 - 20 blood transfusions or when the serum ferritin level has reached 1000 microgram/L. In children, the earliest age at which therapy with Desferal should be undertaken is 2 to 3 years (see “PRECAUTIONS”).

Dosage:

The lowest effective dose should be used.

In most patients average daily doses of 20 to 60 mg/kg body weight are adequate. Patients with a serum ferritin level of less than 2000 microgram/L require about 25 mg/kg/day. Patients with a serum ferritin level between 2000 and 3000 microgram/L require about 35 mg/kg/day. Patients with higher serum ferritin levels may require up to 55 mg/kg/day. It is inadvisable to regularly exceed an average daily dose of 50 mg/kg/day except when very intensive chelation is needed in patients who are no longer growing. If ferritin values fall below 1000 microgram/L, the risk of Desferal toxicity increases. Therefore, it is important to monitor these patients particularly carefully and to consider lowering the total weekly dose.

Note that the doses recommended represent the average daily dose. Since most patients receive the drug on less than 7 days per week, the actual dose per infusion usually differs from the average daily dose (e.g. if an average daily dose of 40 mg/kg is required and the patient receives the drug on 5 days per week, each infusion should contain 56 mg/kg).

To assess the chelation therapy, individual iron balance can be calculated based upon the amount of iron excreted in the urine. Negative iron balance is considered to be achieved when the total amount of iron excreted in the urine, plus a further 50% (which corresponds roughly to the mean iron excretion in the stools), exceeds the total iron received from blood transfusions (each 100 mL of pure red blood cells contains 116 mg of iron). The expected rate of excretion of iron lies in the range of 10 to 20 mg/day. To assess the response to chelation therapy, 24-hour urinary iron excretion should be monitored daily initially and the response to increasing doses of Desferal established. The lowest effective dose of Desferal resulting in a negative iron balance should be used. Once the appropriate dosage has been established, urinary iron excretion rates should be assessed at intervals of a few weeks.

Alternatively, the mean daily dose may be adjusted according to the ferritin value to keep the therapeutic index less than 0.025 (i.e. mean daily dose of Desferal in mg/kg divided by the serum ferritin level in microgram/L is below 0.025)[see “PRECAUTIONS”].

My daily dose is 3 grams (6 vials of 500 mg = 3000 mg ). 

Which means I'm using 50 mg/kg body weight (which is 60 kgs)/per day. (I use it 6 nights a week)
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If your daughter is using one vile (which I'm assuming it's a 500 mg vial) to (14.515 kg which is about 32lb)/per day

Then her average daily dose is 34.5 mg/kg body weight/day.

So they may just increase her daily dose to more then 34.5 mg/kg body weight/day.

However if they still use the same mg.  Then she will need to weigh about 29 kg's (63.9341 lb) to go on 1000 mg (Which is 2 vials of 500 mg). 

By the sounds of these calculations it seems they may just increase her daily dose because she needs to double her weight to stay on 34.5 mg/kg body weight/day


Converstions:

1 gram = 1000 mg
1 kg = 2.2046 lb

P.s. Please correct me if I'm wrong.