I have been on avonex for 6 years. It took like 12 weeks to get use to it. I had bad flu like symptoms. The remaining time was a crap shoot. Some weeks I was fine, some weeks I was weak and had a fever. I recently had a mri showing multiple new brain lesions and my neuro wants me to change meds. Of course because I just got the new avonex pen. It would take me several minutes some weeks to inject myself.