Gilenya and Tecfidera are both disease-modifying oral medications approved for the treatment of MS. Both are equally effective although Tecfidera is more likely than Gilenya to be discontinued within 24 months. Gilenya is approved to treat adults and children aged 10 and older and Tecfidera is only approved for adults over the age of 18. Common side effects of Gilenya include heart rhythm disturbances, diarrhea, infections, and elevations in liver enzymes and common side effects of Tecfidera include flushing, gastrointestinal disturbances, and infections. Tecfidera is slightly more expensive than Gilenya.