First, to Chirpy: my neurologist was very firm with me about IVIG. He said that when I started to lose strength, that meant the myelin coating was being damaged. The myelin will grow back, but not always quite as well. So, repeated events of loss of strength meant that there might be a gradual long-term damage to the nerves. So, his guidance was that if I started to notice significant weakness, I should schedule an IVIG right away. My clinic was very accomodating, so I had no trouble doing that, and in fact I did move up my schedule a couple of times. If you are getting noticably weaker between IVIGs, you might talk to your doctor about going back to the three week schedule. Or, maybe getting a somewhat higher dose, which might last longer...? Unlike some folks, I had no real problems with the IVIG itself, except that I was drained on the day of the treatment, but going just from a three-week interval to a four-week interval really made life easier.
Now, about Imuran: it is a tablet. I take a 50 mg tablet twice a day, total of 100 mg a day. I know another CIDP patient who takes 250 mg, so I suppose the optimum dose might vary from person to person. If I take it on an empty stomach, it makes me slightly nauseated, but if I take it after a meal there is no problem at all, so that is what I try to do. Even if I forget and take it on an empty stomach, it is really not bad. I actually take the generic form, azathioprine, which is not too expensive.
Imuran lowers both your platelets and white blood cell count (WBC). So if you start on Imuran, your doctor will probably ramp you up slowly, and have regular blood tests at first, until he is sure your platelets and WBC don't get too low. Both my platelets and WBC are reduced, but still in the acceptable range. I got blood tests every two weeks at first, now every six months, and it seems to be stable.
The long-term effects are that you are more prone to infection, and to skin cancer. So, you will probably be instructed on things to do to avoid those problems. I am now obsessive about washing my hands, and avoiding sources of infection. I really try to avoid sick people, although can be somewhat hard to do. I know some people with suppressed immune systems avoid crowds, but I have not gone that far yet. I was advised to start wearing sun block when I go into the sun, which I am pretty good about, and to wear a hat in the sun, which I am not so good about. Fortunately, a dermatologist told me that I have a type of skin which is not too prone skin cancer.
I was afraid that I would be sick all the time, but it hasn't worked out that way. All I have had is a few colds. However, they do seem to drag on longer than they used to. I am not supposed to get a flu shot because my CIDP came on shortly after getting a flu shot. So, I dread the thought of getting the flu. But so far, it has not been a problem.
Hope this helps.