Itraconazole reduces the clearance of 
busulfan by a modest 20%. There is some limited evidence that 
ketoconazole may increase the risk of 
hepatic veno-occlusive disease in those given high-dose 
busulfan. 
 Although the rise in levels is only moderate, it would be prudent to monitor for 
busulfan toxicity. Fluconazole appears not to interact, and so may be a useful alternative.