I modified the one I had for Copaxone to use with 1 mL insulin syringes to give my testosterone shots in shoulder. All depends on syringe/volume Avonex is in. I think any autoinjector when used with large enough gauge needle will push it i.m. I use 25gauge for oil based testosterone no problem. 1/2 inch long needle. Takes about 7 seconds. Don't feel a thing. How many mL is Avonex? The Copaxone autoinjector used with 1mL syringe is good for .6 mL max. Can't draw it back all the way. Space only allows so much. Larger syringe diameter (3mL) won't fit as is. Could modify that though