regularly where intensive chelation (i.v.) is required, and the dose adjusted accordingly. Implanted intravenous systems can be used when intensive chelation is carried out.
Care should be taken when flushing the line to avoid a sudden infusion of residual Desferal which may be present in the dead space of the line, as this may lead to flushing, hypotension and circulatory collapse (see section 4.4 Special warnings and precautions for use).
Diagnosis of iron storage disease and certain anaemias
The Desferal test for iron overload is based on the principle that normal subjects do not excrete more than a fraction of a milligram of iron in their urine daily, and that a standard intramuscular injection of 500 mg of Desferal will not increase this above 1 mg of iron (18 micro mol). In iron storage diseases, however, the increase may be well over 1.5 mg (27 micro mol). It should be borne in mind that the test only yields reliable results when renal function is normal.
Desferal is administered as 500 mg intramuscular injection. Urine is then collected for a period of 6 hours and its iron content determined.
Excretion of 1-1.5 mg (18-27 micro mol) of iron during this 6-hour period is suggestive of iron overload; values greater than 1.5 mg (27 micro mol) can be regarded as pathological.
Treatment for aluminium overload in patients with end stage renal failure
Patients should receive Desferal if:
- they have symptoms or evidence of organ impairment due to aluminium overload
- they are asymptomatic but their serum aluminium levels are consistently above 60 ng/mL and associated with a positive Desferal test (see below), particularly if a bone biopsy provides evidence of aluminium related bone disease.
The iron and aluminium complexes of Desferal are dialysable. In patients with renal failure their elimination will be increased by dialysis.
Adults and children:
Patients on maintenance haemodialysis or haemofiltration: 5 mg/kg once a week. Patients with post-desferrioxamine test serum aluminium levels up to 300 ng/mL: Desferal should be given as a slow i.v. infusion during the last 60 minutes of a dialysis session (to reduce loss of free drug in the dialysate). Patients with a post-desferrioxamine test serum aluminium value above 300 ng/ml: Desferal should be administered by slow i.v. infusion 5 hours prior to the dialysis session.
Four weeks after the completion of a three month course of Desferal treatment a Desferal infusion test should be performed, followed by a second test 1 month later. Serum aluminium increases of less than 50ng/mL above baseline measured in 2 successive infusion tests indicate that further Desferal treatment is not necessary.
Patients on CAPD or CCPD:
5 mg/kg once a week prior to the final exchange of the day. It is recommended that the intraperitoneal route be used in these patients. However, Desferal can also be given i.m., by slow infusion i.v. or s.c.
Diagnosis of aluminium overload in patients with end stage renal failure
A Desferal infusion test is recommended in patients with serum aluminium levels > 60ng/mL associated with serum ferritin levels >100 ng/mL.
Just before starting the haemodialysis session, a blood sample is taken to determine the baseline level serum aluminium level.
During the last 60 minutes of the haemodialysis session a 5mg/kg dose is given as a slow intravenous infusion.
At the start of the next haemodialysis session (i.e. 44 hours after the aforementioned Desferal infusion) the second blood sampl |
