6MP question

I'd like to get some input on a medication change my doctor is prescribing.

6MP has been working well - initially tapered up to 100mg and symptoms improved greatly but I was still symptomatic (no blood but D & 3-4 BM/day, minor pain). 6MP metabolite test showed blood levels that were in the sub-therapeutic range and liver health indicator also below danger level. Based on those levels and my body weight, dose was increased to 150mg/day and test repeated.

At that point the test showed good therapeutic range but hepatotoxicity indicator too high. Dose reduced to 125mg and retested - hepatotoxicity still too high.

Doctor is prescribing go completely off 6MP for 1 week then start back at 100mg.

I've definitely noticed an increase in pain and frequency just going from 150 to 125mg. My concern is that going completely off 6MP for a week might start a downward spiral that might be difficult to turn around even after starting back on the 6MP.

Any input here is appreciated. I know the priority needs to be to avoid long term liver damage - even a bad flare is better than that, but I'd rather avoid both...

Test results:

@100mg
6-TGN = 182 (range 230-400)
6-MMPN = 3350 (range <5700)

@150mg
6-TGN = 318
6-MMPN = 9939

@125mg
don't have the numbers

I used allopurinol with 6mp for a while and it drastically improved my #s. The problem is that you need to get frequent blood work when you get going on the combo because it can cause neutropenia. Usually they reduce your dose of 6mp by A LOT when they add allo but they didn't for me so I ended up with neutropenia and I had to go to a hemotologist ALL the time - seriously like 2 or 3x a week for a while. it was terrible. it used to be a lot less common to use them in combo but I see more people doing it now...

If you are getting worse right after dropping 25 mg than maybe you are just deteriorating at the same time that your stopped
But I can't say for sure

Good luck

I was unaware of the 6MP/Allopurinol combination so really good information suggestion there, will look more into it and discuss with the doc.

@NSSG What blood test/indicator(s) do they look at to guard against Neutropenia or other problems with that drug combo? I'm assuming WBC and Neutrophils, but anything else? How often are blood tests advised when starting the combo - 2x/wk?

I have a feeling my doc might be less familiar with this combo and the issues so I'll definitely want to make sure I'm getting tested enough and looking at the right indicators. At this point it's really the 1 week off 6MP that I'm concerned about, hopefully won't start a serious flare. I have a call in to his nurse to see if he thinks it's a good idea to use prednisone or something during that week off 6MP.

Thats what I thought too