re: IV Vitamin B12 in hemodialysis patients

Hi All,
Is anyone out there using IV vitamin B12 in their patients on hemodialysis? We have been using this route (100 mcg IV q3 mo)for some time now but we can't find any good references for using this route. One reference states that IV administration of B12 results in excessive excretion and loss of B12 in urine (although it could be argued that since this population may not produce much urine . . .. Thanks for your help,
Anna