CsA-associated neurotoxicity and ineffective prophylaxis with clonazepam in patients transplanted for thalassemia major: analysis of risk factors.

Cyclosporin A (CsA) has been shown to be useful in the prophylaxis of acute graft-versus-host-disease (GVHD). However, this immunosuppressive agent produces multiple side-effects including nephrotoxicity, hypertension, hypertricosis, gum hyperplasia, infections, and neurotoxicity. We report a retrospective analysis of neurotoxicity in 625 recipients transplanted for thalassemia and given CsA as part of GVHD prophylaxis. Neurotoxicity consisted in mental status changes, tremor, headache (grade 1), visual disturbance and cortical blindness (grade 2) and seizures and coma (grade 3). The overall toxicity was 28.8% and the incidence of convulsions was 10.1%. Neurological findings were reversible after temporary reduction or discontinuation of CsA. Class 3 patients, when prepared with protocol 6 (Bu 14 + Cy 200 and CsA for GVHD) or when they developed acute GVHD, had the highest risk of convulsions. Age, sex, different conditioning regimens, different anticonvulsive prophylaxis, liver damage due to iron-overload and/or to chronic inflammation did not influence the occurrence of CsA-related CNS toxicity. The occurrence of acute GVHD with concomitant use of high-dose corticosteroids is the single significant predisposing factor in the occurrence of convulsions. Grades 1 and 2 of neurotoxicity occurred earlier and were not influenced even by acute GVHD.