The internets is a wealth of information, compiled mostly by those with an axe to grind. this site in some repsects also adheres to this model. I am not being critical, it is just a fact of life, enforced by human nature.
For you to be able to enjoy a genuine, universal attitude of a given subject, you need to look at more than anonymous, opinion based literature (aka the www).
Scientific studies have shown that Avonex is an inferior DMD than Tecfidera. Also as Tecfidera is an oral therapy, you do not have to carry around needles, or the complications that can come from injection sites on the body.
I do not know what horror stories you have found on the internet; but i am sure they are 99% not applicable to you. for example, not every headache is a brain tumour!
Tecfidera is excellent. If you have any side effects once you start, come and search in here to find what positive stores have been shared to successfully deal with them, in order to continue on with one’s enjoyment of this life.
As far as other meds restriction due to Tecfidera… i believe ibuprofen is frowned upon, if taken as a regular, fairly high dose medication. other than… i am not sure. You will have to consider your own personal drug taking regime. I hear that birth control methods might be impacted… if applicable to your gender?
Good luck and be optimistic!