High-dose 
ciclosporin markedly raises 
etoposide serum levels and increases the suppression of white blood cell production. Severe 
toxicity has been reported in one patient. 
 Some have suggested reducing the dose of 
etoposide by 40 or 50%. The use of high- dose 
ciclosporin for multidrug resistant tumour modulation remains experimental and should only be used in 
clinical studies. Concurrent use should be very well monitored.