I have a few questions for you to ask your health insurance.
Are they not covering the Imuran under the prescription plan?
If they don't cover it under the prescription plan, will they pay for it under major medical?
My insurance won't pay for the syringes I need to do my methotrexate under my prescription plan, but will cover it under my major medical. They don't pay for anything to do with injectables under the Rx plan, but do pay for it all under major medical, which I need to submit separately.
So, that would be a good place to start. Then, you need in writing the info as to why they won't pay for it.
If they won't pay for it at all, then I would check out the $4 plan that Walmart or Target have to see if they will cover it there.
Next, you have the chance to go to the manufacturer and ask for coverage under their benefit plan where they pay for the drugs if you can't afford them. Each company has a different name for the plan. You and your doctor will need to fill in a lot of info, but then on you won't have to pay for it and will get it. Some companies send the meds to the doctor to be given out, and others send them to you.
There are a few more options, but these will get you started.
[I processed health insurance claims before I went out on disability with lupus.]