Is leukopenia a described side-effect of bicalutamide (Casodex)?/nBackground: A 76-year-old man wit

Fråga: Is leukopenia a described side-effect of bicalutamide (Casodex)? Background: A 76-year-old man with prostate cancer received bicalutamide as monotherapy. The treatment started in September 1999 with 150 mg bicalutamide per day, in February 2000 the dose was lowered to 100 mg/day. Controls of blood-samples during the period of treatment showed a decrease in the white cell count. The lowest value was found in March 2000 when the white cell count was 3.0 x 10(9) /L. The normal range is 4.0 - 10.0 x 10(9) /L. Before treatment with bicalutamide the value of the white cell count was normal and when treatment with bicalutamide was discontinued in March the white cell count became normalised again. The patient began treatment with goserelin (Zoladex) instead.

Sammanfattning: The literature concerning bicalutamide and leukopenia as an adverse effect is limited. The occasional cases which have been reported after administration of an androgen antagonist suggest that it might be possible for this group of substances to exert negative effects on the blood cells. Further studies and evaluations are needed to conclude if there is a casual relationship.

Svar: Bicalutamide is a non-steroidal antiandrogen (1). It exerts its effect by binding to androgen receptors and thereby blocking the effect of androgen stimulation, which leads to regression of prostatic tumours.

There are articles in which the risk of developing anaemia while treated with bicalutamide and similar compounds (ex flutamide) are discussed (2). There is also one case report in Drugline concerning anaemia during bicalutamide treatment (3).

A thorough literature search including Medline, Drugline, Embase and common pharmacological handbooks has only revealed little information about leukopenia as an adverse reaction to bicalutamide treatment. No cases of hematological adverse effects have been reported to SADRAC (The Swedish Adverse Drug Reactions Advisory Committee) in relation to bicalutamide treatment. However, three cases have been reported for the group androgen antagonists (4). These three cases concern thrombocytopenia, aplastic anaemia, and pancytopenia. The WHO adverse drug reaction monitoring centre has only received two reported cases of leukopenia for bicalutamide. However, these reports are not evaluated due to the different reporting systems in the participating countries (5). The literature study resulted in one case report describing a patient with prostatic cancer, who developed a severe reversible neutropenia following treatment of flutamide, which is related to bicalutamide. Neutrophil count returned to normal after discontinuation of flutamide; this indicates that flutamide may have contributed to neutropenia (6).