Hi Bri! If you have stomach pain when taking azathioprine you need to tell your doctor immediately - some of the side effects may indicate serious problems.
I don't know who told you that azathioprine is "safer than steroids", I'm sure in some senses it might be, but azathioprine does not replace pred in either PMR or GCA. At best it may mean you can manage on a lower dose of pred but there is mixed evidence that it works reliably. Azathioprine DOES NOT have any effect on the GCA/PMR, it makes your body use the pred differently. However, it is only worth trying if it doesn't make the patient ill. I know others who could tolerate neither methotrexate nor azathioprine.
Many of us on here and other forums have had GCA and/or PMR for very much longer than 2 years and have coped well on pred alone. With GCA you would expect to be on pred for at least 2 and a half years even if you were able to reduce steadily from the starting dose without ever having a flare. Unfortunately our experience has been that the suggested reduction schemes don't work for many people, they are too fast or in too big steps. We have worked out reduction schemes that go in smaller steps at any one time but are not really slower overall as the patients rarely, if ever, have problems reducing from one dose to the next. We believe that many "flares" are not really a return of the disease but the body being unable to cope with lowering the steroid dose so fast.
My version of reduction is this:
"A group of us worked out reduction schemes individually that have allowed us to reduce far further than ever before but they are all basically the same - and they were based on a scheme a Swedish gentleman worked out when he simply couldn't get below 3mg without pain. Img at that level is 33%, 1/2mg is 17% - way above the 10% that has been recommended for years. So he used table to see the daily doses and took the new dose on one day, old dose for a few days and then proceeded by repeating that and then reducing the number of days of old dose - until he got to everyday new dose. It worked, he got off pred and has been off pred for at least 3 years (it could be longer). Something similar to mine is being tried by a consultant rheumatologist in the north of England and he too finds it works for every single patient he has given it to. As it did for several ladies beforehand.
My reductions are VERY slow. I use the following pattern to reduce each 1mg:
1 day new dose, 6 days old dose
1 day new dose, 5 days old dose
1 day new dose, 4 days old dose
1 day new dose, 3 days old dose
1 day new dose, 2 days old dose
1 day new dose, 1 day old dose
1 day old dose, 2 days new dose
1 day old dose, 3 days new dose
1 day old dose, 4 days new dose
1 day old dose, 5 days new dose
1 day old dose, 6 days new dose
By that stage if I feel OK I feel safe to go all new dose. I suppose you might be OK starting and stopping at "1 day new, 4 days old" but I was terribly sensitive to steroid withdrawal pain so I err on the safe side. Once you get to the "everyday new dose" - if you feel OK you can start on the next reduction, no real need to spend a month at the new dose.
This avoids steroid withdrawal pain - which is so similar to PMR pain that you often can't tell which is which and some of us suspect that many flares are NOT the PMR returning but problems with steroid withdrawal. Using a scheme like this also means you can stop immediately if you have any problems - you might be fine at one day old dose, 2 days new (lower) dose but not at a 3 day gap - but you have dropped your dose a lot and that is the idea. It also isn't as slow as you would think - you can reduce at a rate of about 1mg/month on a continual basis."
A similar scheme has been offered to a consultant in the northeast of England and he also finds it has worked in all the patients he has tried it with.
It would be worth discussing using this sort of reduction with your doctor. Return to pred alone and try this approach.
But for the moment - back to the doc as soon as you can get to see them. I would ask your GP for an emergency appointment if it were me.