The manufacturer of deferasirox (Exjade) has received postmarketing reports of cases of sometimes fatal acute renal failure. The labeling of the iron-chelating agent, which is used in the treatment of chronic iron overload attributable to blood transfusion in patients two years of age or older, has been revised to reflect information obtained from ongoing clinical trials and data reported by practitioners.

Deaths have occurred most often in patients with several comorbidities who are in an advanced stage of a hematologic disorder. Although deferasirox's prior labeling noted that the drug could elevate the serum creatinine level, the revised label conveys a much stronger warning of the possible consequences of that risk.

Nurses should be aware that patients who are to receive deferasirox should have a second baseline serum creatinine level determined (to confirm the results) and monthly assessment of that level during therapy. If the patient has risk factors for renal disease (such as concurrent administration of drugs that depress renal function, older age, or the presence of comorbidity), she or he should be monitored weekly for the first month of treatment (or after modification of it) and then monthly. If nurses identify elevations in the serum creatinine level, they should contact the prescriber for new orders-the drug should be withheld for a period of time, the dose reduced, or the therapy discontinued. If the drug is reintroduced after the serum creatinine level has returned to within the normal range, an initial dose lower than the one previously prescribed should first be used and gradually increased.

Deferasirox's labeling also advises of reports of another sometimes fatal adverse effect: cytopenia, which can appear as agranulocytosis, neutropenia, or thrombocytopenia. At present, the relationship between deferasirox and the development of cytopenia has not been established; most of the afflicted patients had existing hematologic disorders and bone marrow failure, but the contributive effect of the drug cannot be excluded. Because of that possible adverse effect, nurses should confirm that complete blood counts are assessed regularly (the label information is not specific about the interval). Patients who develop an inexplicable cytopenia should suspend deferasirox until blood counts return to normal or the cause of the cytopenia is identified.

Also added to the deferasirox warning is the fact that serious hypersensitivity reactions, such as anaphylaxis and angioedema, have been reported in the use of the drug, most within the first month of treatment. The warning of possible liver damage is not new, but it's important to note that levels of serum transaminase-also known as serum glutamic-pyruvic transaminase (SGPT) and alanine transaminase (ALT)-might rise significantly with use of the drug. Blood work for those liver enzymes should be performed monthly throughout deferasirox therapy, which should be discontinued in the event of extremely or persistently elevated levels. Nurses should emphasize to patients the importance of follow-up blood work for all of the possible adverse effects of deferasirox.