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Options with azathioprine

Hi all. Been on azathioprine since April 2016. For the first year I took 50mg and felt like it did nothing for me and was getting symptoms all the time. I then upped to 75mg and finally found improvement and had a good colonoscopy. I was on 75mg for 6 months when the nurse phoned and said my WBC count has been steadily dropping each month and has now gone below normal range. So I reduced back down to 50mg and have been on that for the past 11 months and still continued to feel good until the past few weeks. I now seem to be entering a flare.

What I think is happening is 50mg is not sufficient for me yet any more and my WBC becomes abnormal. I really want to go back up to 75mg is there not any solution??


Well-known member
San Diego
Can you switch to methotrexate? Has that already been tried? Or failing the methotrexate, how about moving up to a biologic?
As far as I am aware azathioprine dosing escalates depending to your weight.
A subtheurapeutic dose could lead to the recurrence of symptoms.
I think it's time you make an appointment with your doc and examine every other possible alternative for you.

Lady Organic

Staff member
Hi, I have been dealing with this situation for years except I am on purinethol (cousin to aza).
Before giving up on aza, you could do trials to find your ''sweet spot'', for instance alternate one day at 50mg and the other day at 75mg and see if this can put you back on remission and if WBC is fine. There are ''regular dosages'' with this medication, but in fact, we can play with it. Thats what I have been trying to make happen with my GI, we tried many different dosages with hopes. Unfortunately, in my case I still dont get enough medication to stay in remission like I was before for years at a higher dose. It seems I will have to escalate to a biologic since methotrexate has been a fail. Good luck!


Staff member
You can try Azathioprine with Allopurinol. This makes the metabolite that keeps the Crohn's under control go up and the metabolite that causes your WBC to drop, to go down.

We did this for my daughter when she was found to have sub-therapeutic 6-TGN levels and high 6-MMP levels (makes WBC go down). Her WBC was ok at that time, but we couldn't risk increasing Azathioprine because her GI said it would go right down.

So we added Allopurinol. It did work, in the sense that her 6-TGN level went up. But she had already been getting a lot of infections, and after adding Allopurinol, it got worse, so we had to stop Azathioprine eventually. We moved on to a biologic, but only because she had been on MTX previously and we knew she couldn't tolerate it.

The therapeutic efficacy, bone marrow toxicity, and liver toxicity of azathioprine (AZA) and 6-mercaptopurine (6-MP) may be related to their metabolites: 6-thioguanine (6-TG) and 6-methylmercaptopurine (6-MMP). AZA is a prodrug that is metabolized to 6-MP, which is then further metabolized along an anabolic pathway to several metabolites including 6-TG and 6-MMP. Two enzymes are responsible for catalyzing these reactions: thiopurine methyltransferase (TPMT) and hypoxanthine phosphoribosyl transferase (figure 1). 6-TG levels between 230 and 400 may correlate with response and remission of inflammatory bowel disease. Bone marrow suppression may correlate with elevated levels of 6-TG greater than 400, while elevated levels of 6-MMP levels greater than 5700 may correlate with liver toxicity, manifested as increased liver enzymes.

my little penguin

Staff member
Ds had to switch from 6-mp (sister drug to aza) due to elevated liver enzymes.
He tried allopurinol but could never get to therapeutic levels without raising his liver enzymes again
Tried the every other day etc...
Just didn’t work
So Ds was switched to methotrexate at the time

Good luck