Does anyone have any experience of Azathioprine? ('Imuran' in non-generic - in U.S., at least). I have just begun it, substituted for Plaquenil, which was working very very slowly, if at all, by my rheumatologist. It is for my main symptom, profound fatigue (PEM etc), with Sjogren's, and PMR, now under control. I felt horrible, sick headache, etc., just for a few hours, about 5 hours after each dose. I'm inclined to return to Plaquenil, which at least had no noticeable side effects! Apologies if this is already a thread - I couldn't find it. Thanks for any input!