Ud over faldet i antal blodceller, som er lægemidlets tilsigtede virkning, er de alvorligste bivirkninger af Busilvex infektioner, leversygdom, herunder tillukning af en levervene, transplantat- mod- vært - reaktion (når de transplanterede celler angriber kroppen) og luftvejssygdomme.
Apart from the decrease in blood cell counts, which this is the intended effect of the medicine, the most serious side effects of Busilvex are infection, liver disorders including blocking of a liver vein, graft versus host disease (when the transplanted cells attack the body) and respiratory (lung) disorders.