Hi, I've taken azathioprine for several years now. I also was very concerned about side effects when I started the drug. It's important to start slow and work up to the full dose, otherwise there may be some nausea or stomach upset. But once I was on the full dose, I didn't notice any problems. I believe most doctors do regular blood work for those taking the drug to make sure everything is working properly.
A few months ago i would have told you that azathioprine hadn't made a huge difference for me. But recently, because of a mix-up with a new insurance plan, I ran out and just didn't get the Rx refilled. I didn't take my normal dose for about 6 weeks. This put me into a nasty flare that is just now coming under a bit of control. Without question, the azathioprine was helping me much, much more than I knew. It's that old saying: you don't miss the creek 'till the well runs dry.
At any rate, as your son is having so many problems and his physician has recommended the medication, it seems a sound idea. Talk to his doctor about your concerns. Ask about keeping close watch on liver and kidney function and other things via regular blood work.
And in the end, make the decision we each much make by balancing the good with the potential bad and doing the best you can at the moment.
Good luck and keep us posted. Please tell your son we'd love to have him post, as well. There are several men who are regulars here and to whom he may be well able to relate. Otherwise, I believe the effects of this disease transcend gender. We would be glad to talk to your son and answer his questions.
Sunny