Minimal incidence of neurotoxicity without prophylaxis during busulfan-based conditioning regimen in patients undergoing stem cell transplantation

Busulfan (Bu), an alkylating agent, has been used in pre-transplant conditioning regimens since the 1950s, due to its potent myeloablative effect. Questions have been raised regarding oral or intravenous formulations, although both are known to be associated with serious side effects, including hepatic veno-occlusive disease, and neurotoxicity. The administration of anticonvulsant prophylaxis has become more common during high-dose Bu-based conditioning regimen; however, anticonvulsants can interfere with Bu pharmacokinetics and may have their own side effects, which can affect the outcome of the transplant. Our objective was to analyze the incidence of neurotoxicity in patients who underwent stem cell transplantation with high-dose Bu-based conditioning regimens without anticonvulsant prophylaxis. Ninety-seven patients were included, either having received a dose of 12 mg/kg (n = 73) for allogeneic transplantation or 16 mg/kg (n = 24) for autologous transplantation. The incidence of seizures was 0.01 %. We conclude that anticonvulsant prophylactic regimens may be unnecessary, and reduction of their use may help to avoid potential drug interactions and undesired side effects.