Abstract
Dear Editor:
Block et al. (p. 1269) respond to an earlier Letter that we had published in the February 2009 issue of the Journal. 1 Block et al. state that the liver failure in our patient might have been caused by her previous chemotherapy. They question whether the patient used other hepatotoxic drugs and express their doubt concerning the hepatotoxicity of Anvirzel (Nerium Biotechnology, San Antonio, TX), especially with regard to its being “natural.” They also mention that there have been no human cases of hepatotoxicity caused by oleander-based products. We would like to respond to these statements. Prior to her presentation with hepatic failure, our patient's liver-function tests were within normal limits even during her six courses of ifosfamide–etoposide chemotherapy throughout her 1-year regimen. We believe that the alleged hepatotoxicity of either drug would have been observed during this time period. We agree that it was still possible for her last chemotherapy dose to cause a delayed idiosycnratic hepatotoxic reaction. In the literature, the most delayed case of hepatotoxicity related to these drugs was observed within the first 3 months after the administration of the last dose. 2 –4 However, our patient's liver-function tests showed deterioration nearly 5 months after her last chemotherapy session. She did not use any other medications except 50-mg tramadol tablets t.i.d. for the last year and Anvirzel for the last 2 months. We reasonably assumed that the most recently added “medication” was responsible for her liver failure.
Block et al. (p. 1269) suggest that there were no data indicating hepatotoxicity of oleander extract in rodents or canines. As we mentioned in our original Letter, we wish to reiterate the data cited by by Adam et al. 5 regarding hepotocyte necrosis in sheep poisoned by oleander leaves. Admittedly, up to now, there have been no reported human cases of hepatotoxicity by oleander-based products. However, their use remains rare and outside the established clinical practice, which might explain the lack of such data.
We are entirely in agreement with Block et al. (p. 1269) that such drugs or “natural products” should be thoroughly researched and their side-effect profiles established before they are prescribed to patients who have cancer.