After 1.5 days without because insurance denied the 240mg dose which follows/gets billed only 1 week after 120mg, I got it handled within 1 business day once I didn't take pharm's answer of "we're working on it". Don't tell me you're working on it, tell me what the problem is & i'll get it done! Done.

Side effects - honestly, i'm a little hot when I go to bed & lay there with fan on till I awake 3am & turn it off.
Stomach - maybe? a tad of ache for an hr or none at all. No bowel effect & I have a colostomy. I do take a low dose of iron to up my red blood count which, constipates so no change from tecfidera.
If it's giving any of you stomach aches, there's quite a few chemo med effect meds for that.
I urinate a good 1/2-3/4 gallon every day (drink much water during day) which also will keep most effects away.
Undocumented fact if you ask a Rebif nurse about drinkng 1/2 gallon of water per day to squash effects. Helped me a ton back then, drank all that water since dx.