e is taken to determine the serum aluminium level once more.
An increase in serum aluminium above baseline of more than 150 ng/mL is suggestive of aluminium overload. It should be noted that a negative test does not completely exclude the possibility of aluminium overload.
Theoretically 100 mg Desferal can bind 4.1 mg Al+++.
Use in the elderly
No special dosage regime is necessary but concurrent renal insufficiency should be taken into account.
4.3 Contraindications
Hypersensitivity to desferrioxamine mesilate unless the patients can be desensitised.
4.4 Special warnings and precautions for use
Renal impairment
Desferal should be used with caution in patients with renal impairment since the metal complexes are excreted via the kidneys. In these patients, dialysis will increase the elimination of chelated iron and aluminium. Isolated cases of acute renal failure have been reported (see also section 4.8 Undesirable effects). Monitoring patients for changes in renal function (e.g. increased serum creatinine) should be considered.
Neurological impairment
Used alone Desferal may exacerbate neurological impairment in patients with aluminium-related encephalopathy. This deterioration (manifest as seizures) is probably related to an acute increase in brain aluminium secondary to elevated circulating levels. Pretreatment with clonazepam has been shown to afford protection against such impairment. Also, treatment of aluminium overload may result in decreased serum calcium and aggravation of hyperparathyroidism.
Rapid intravenous infusion
Treatment with Desferal by the intravenous route should only be administered in the form of slow infusions. Rapid intravenous infusion may lead to hypotension and shock (e.g. flushing, tachycardia, circulatory collapse and urticaria).
Instructions for use and handling
Desferal should not be administered s.c. in concentrations and/or doses higher than those recommended as local irritation at the site of administration may occur more frequently.
Infections
Patients suffering from iron overload are particularly susceptible to infection. There have been reports of Desferal promoting some infections such as Yersinia enterocolitica and Y. pseudotuberculosis. If patients develop fever with pharyngitis, diffuse abdominal pain or enteritis/enterocolitis, Desferal therapy should be stopped, and appropriate treatment with antibiotics should be instituted. Desferal therapy may be resumed once the infection has cleared.
In patients , receiving Desferal for aluminium and/or iron overload there have been rare reports of mucormycosis (a severe fungal infection), some with fatal outcome. If any characteristic signs or symptoms occur Desferal treatment should be discontinued, mycological tests carried out and appropriate treatment immediately instituted. Mucormycosis has been reported to occur in dialysis patients not receiving Desferal, thus no causal link with the use of the drug has been established.
Visual and hearing impairment
Disturbances of vision and hearing have been reported during prolonged Desferal therapy. In particular, this has occurred in patients on higher than recommended therapy or in patients with low serum ferritin levels. Patients with renal failure who are receiving maintenance dialysis and have low ferritin levels may be particularly prone to adverse reactions, visual symptoms having been reported after single doses of Desferal. T |
