I love tecfidera. taking the 120mg pills, i had one daily for the first week, then 2 for week two, 3 for week three and then 4 for the 100% daily dose in week four.
Side effects were slight stomach cramps - immediately cured with paracetamol. (Maybe six occasions, lasting no more 30 minutes during week 2.)
Itching (considered to be caused by the same mechanism as flushing) - resolved immediately with anti-histamines. (Lasted for about a week around week 4)
Side effects were mild and short lived. You really should not worry.
Any sense of nausea, especially at the beginning are likely to be more due to psychosomosis or simple anxiety. They hit me usually within 30 minutes of my morning pill and lasted no more than 5 minutes.
Flushing (redness and heat in face / skin) has been limited to a rare one or two minutes of prickly sensation. Aspirin is supposed to undermine flushing. I take a daily aspirin anyway. No where has my skin colour redened.
As mentioned by red lou above, taking the Tec on a full stomach, (not just a snack or ‘with food’) will ensure your GI concerns are unlikely to arise.
With all that being said; drugs treat everyone differently; we are all individuals with our own physiology and chemistry and frailties. but from my experience, Tec is pure joy.