Imuran: what blood markers am I looking for?

Hi All,

First time poster, long time lurker...well, for 4 months.

Feel free to skip this background :I was diagnosed in May 2011 but had spontaneous remission after 5 weeks, which suggested acute self limited colitis. So I never started meds until I had another flare 5 months later Oct 2011. Hopped on Pentasa(mesal) and Pred but had a very bad reaction to Pentasa which sent me to hospital for a week. Have now been on Imuran @100mg daily for 3 weeks with no significant side-effects (also on pred 17.5 daily- weaned from 35mg three weeks ago)- and have good bowel motions once a day.

My question is this: what are the specific markers/things on the blood tests that will indicate whether the Imuran is effective? Is there a key marker that changes , and therefore means I can wean of the Pred? Or is it just trial and error? Like I go up to the average dose of Imuran (150/200), observe any side effects, and then wean of Pred to see if it works.

Its not just trial and error is it?

Many thanks

Ben

As far as I know, it used to be more trial and error than it is these days. There is a specific test that can be run that tells you whether you're in the theraputic range for the medication. There are 2 graphs shown in the results for this test (the results I've seen), one shows the level of imuran in your blood and the other shows the toxicity to your liver. If you're in the theraputic range and the toxicity is low, that's the ideal situation. If you're not in the range, and the toxicity is low, they can increase the dose. The situation for me was that I was not in the range and my toxicity was high so I was unable to increase the dose beyond 50mg. The regular blood tests they do are not the same as the prometheus test that shows the levels. The regular CBC and Liver function test can only show whether your CBC is in the healthy range and whether your liver enzymes are normal. You can somewhat tell whether Imuran is having an impact by checking whether a WBC comes back normal/reduced if you were experiencing high WBC due to inflammation. Mine was never TOO high, it was always in the normal range but it has gotten lower since beingg on 6mp.

Yep, spot on notsosicklygirl.
Regular blood work looks for any abnormality especially high white blood count, while the prometheus test is to determine therapeutic range.
Both tests are crucial and take the fear out of Imuran in my opinion. This is an older drug with a great safety profile.
It's not a magic bullet, but it works for many.

Max Imuran dose is 2mg/kg of body weight. In my case, my GI tested me for CBC, liver function test and C-Reactive Protein only.