Hi UpsetMom and Dusty.
Thiopurine metabolites are a tricky area.
6TGN (thioguanine nucleotides)
In studies done in this area, you do need the 6TGN to be above 235, although studies do show benefit upto 400 or so. If the levels get too high, then you can see bone marrow suppression, usual fixed by reducing the dose.
6MMP (methyl mercaptopurine)
Again, studies to show an increased risk of hepatotoxicity (liver inflammation) with levels above 5700, so you would look at your ALT and AST and see if it is trending up. Again, can be fixed with a dose reduction.
The tricky part is the test isn't that accurate - you might see the levels jumping all over the place occasionally, it really depends on how long the blood is kept before doing the test (before 2 days is ideal). Given the test is done infrequently, some labs will stockpile the blood until they get enough requests and then do a bulk run, or perhaps only test a few times per week. Ideally, to get accurate results, you should have the blood tested as soon as possible after collection.
What you can do is repeat the test and watch for a trend. If the levels are stable and the ALT and AST are fine, and there is no evidence of bone marrow suppression (low WCC, low neutrophil count), then continue as is. If there is a some evidence of toxicity, then you can decrease the dose.
With levels of 7750 for 6MMP and 581 for TGN while on Imuran 125, then you could watch the blood tests frequently, or perhaps drop to 100mg of Imuran and recheck levels in four weeks. The other important point would be, what were the levels at 100mg of Imuran, if they were low at that level, then you would be better of holding at 125 and watching the WCC and LFTs (ALT and AST).
Best wishes.
:ghug:
