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Ocular and auditory disturbances have been reported when Desferal was administered over prolonged periods of time, at high doses, or in patients with low ferritin levels. The ocular disturbances observed have been blurring of vision; cataracts after prolonged administration in chronic iron overload; decreased visual acuity including visual loss, visual defects, scotoma; impaired peripheral, color, and night vision; optic neuritis, cataracts, corneal opacities, and retinal pigmentary abnormalities. The auditory abnormalities reported have been tinnitus and hearing loss including high frequency sensorineural hearing loss. In most cases, both ocular and auditory disturbances were reversible upon immediate cessation of treatment (see PATIENT INFORMATION and ADVERSE REACTIONS/Special Senses).
Visual acuity tests, slit-lamp examinations, funduscopy and audiometry are recommended periodically in patients treated for prolonged periods of time. Toxicity is more likely to be reversed if symptoms or test abnormalities are detected early.
Increases in serum creatinine (possibly dose-related), acute renal failure and renal tubular disorders, associated with the administration of deferoxamine, have been reported in postmarketing experience (see ADVERSE REACTIONS). Monitor patients for changes in renal function.
High doses of Desferal and concomitant low ferritin levels have also been associated with growth retardation. After reduction of Desferal dose, growth velocity may partially resume to pretreatment rates (see PRECAUTIONS/Pediatric Use).
Adult respiratory distress syndrome, also reported in children, has been described following treatment with excessively high intravenous doses of Desferal in patients with acute iron intoxication or thalassemia.
Flushing of the skin, urticaria, hypotension, and shock have occurred in a few patients when Desferal was administered by rapid intravenous injection. THEREFORE, DESFERAL SHOULD BE GIVEN INTRAMUSCULARLY OR BY SLOW SUBCUTANEOUS OR INTRAVENOUS INFUSION.
Iron overload increases susceptibility of patients to Yersinia enterocolitica and Yersinia pseudotuberculosis infections. In some rare cases, treatment with Desferal has enhanced this susceptibility, resulting in generalized infections by providing these bacteria with a siderophore otherwise missing. In such cases, Desferal treatment should be discontinued until the infection is resolved.
In patients receiving Desferal, rare cases of mucormycosis, some with a fatal outcome, have been reported. If any of the suspected signs or symptoms occur, Desferal should be discontinued, mycological tests carried out and appropriate treatment instituted immediately.
In patients with severe chronic iron overload, impairment of cardiac function has been reported following concomitant treatment with Desferal and high doses of vitamin C (more than 500 mg daily in adults). The cardiac dysfunction was reversible when vitamin C was discontinued. The following precautions should be taken when vitamin C and Desferal are to be used concomitantly:
- Vitamin C supplements should not be given to patients with cardiac failure.
- Start supplemental vitamin C only after an initial month of regular treatment with Desferal.
- Give vitamin C only if the patient is receiving Desferal regularly, ideally soon after setting up the infusion pump.
- Do not exceed a daily vitamin C dose of 200 mg in adults, given in divided doses.
- Clinical monitoring of cardiac function is advisable during such combined therapy.
In patients with aluminum-related encephalopathy and receiving dialysis, Desferal may cause neurological dysfunction (seizures), possibly due to an acute increase in circulating aluminum (see ADVERSE REACTIONS). Desferal may precipitate the onset of dialysis dementia. Treatment with Desferal in the presence of aluminum overload may result in decreased serum calcium and aggravation of hyperparathyroidism.
Carcinogenesis, Mutagenesis, Impairment of Fertility
Long-term carcinogenicity studies in animals have not been performed with Desferal.
Cytotoxicity may occur, since Desferal has been shown to inhibit DNA synthesis in vitro .
Pregnancy Category C
Delayed ossification in mice and skeletal anomalies in rabbits were observed after Desferal was administered in daily doses up to 4.5 times the maximum daily human dose. No adverse effects were observed in similar studies in rats.
There are no adequate and well-controlled studies in pregnant women. Desferal should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when Desferal is administered to a nursing woman.
Pediatric patients receiving Desferal should be monitored for body weight and growth every 3 months.
Safety and effectiveness in pediatric patients under the age of 3 years have not been established (see INDICATIONS AND USAGE, WARNINGS, PRECAUTIONS: DRUG INTERACTIONS/Vitamin C, and ADVERSE REACTIONS).
Clinical Studies of Desferal did not include sufficient numbers of subjects aged 65 years and over to determine whether they respond differently from the younger subjects. Postmarketing reports suggest a possible trend for an increased risk of eye disorders in the geriatric population, specifically the occurrence of color blindness, maculopathy, and scotoma. However, it is unclear if these eye disorders were dose related. Although the number of reports was very small, certain elderly patients may be predisposed to eye disorders when taking Desferal. Postmarketing reports also suggest that there may be an increased risk of deafness and hearing loss in the geriatric population. (see ADVERSE REACTIONS). In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.
No studies have been performed in patients with hepatic impairment.This monograph has been modified to include the generic and brand name in many instances.
Last reviewed on RxList: 1/5/2012
Additional Desferal Information
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