20 to 50     : Dose as in normal renal function
10 to 20     : 75–100%
<10           : 50–100%
DOSE IN PATIENTS UNDERGOING RENAL REPLACEMENT THERAPIES
CAPD                :Dialysed. Dose as in normal renal function
HD                     :Dialysed. Dose as in normal renal function
HDF/high flux   :Dialysed. Dose as in normal renal function
CAV/VVHD      :Dialysed. Dose as in normal renal function
IMPORTANT DRUG INTERACTIONS
Potentially hazardous interactions with other drugs
Allopurinol: enhances effect with increased toxicity. Reduce azathioprine dose by 50–75% if administered concomitantly
Antibacterials: increased risk of haematological toxicity with co-trimoxazole
Anticoagulants: possibly reduced anticoagulant effect of coumarins
Antipsychotics: avoid concomitant use with clozapineCiclosporin: ?decreased ciclosporin absorption and bioavailability
Cytotoxic agents may be additive or synergistic in producing toxicity, particularly on the bone marrow
ADMINISTRATION
Reconstition
Add 5 mL water for injection to each vial (50 mg)
Route
Oral, IV
Rate of Administration
Over not less than 1 minute
Comments
Some units dilute to 100 mL sodium chloride or glucose 5% and infuse over 1 hour.
IV bolus peripherally, preferably in the side arm of a fast-running infusionVery irritant to veins. Flush with 50 mL sodium chloride 0.9% after administration
Take tablets with or after food
OTHER INFORMATION
Extensively metabolised to mercaptopurine
1 mg by IV injection is equivalent to 1 mg by oral route
6-mercaptopurine levels can be monitored in patients with low urate clearance
Monitor white cell and platelet counts
Cytotoxic Drug – Do Not Handle Can be given as an intermittent infusion (up to 250 mg in 100 mL)