Yes, you can stop taking Tecfidera (dimethyl fumarate) abruptly without precipitating any rebound disease activity (unlike some other drugs used for MS such as Tysabri or Gilenya for example). One study reported that most patients who started treatment with Tecfidera at a Swedish clinic had either discontinued it or switched to another treatment within two years.

The reasons for the low persistence rates were thought to be a lack of effectiveness of lack of tolerability. The average time to discontinuation was 366 days and the average time to switching medications was 372 days. Only 43% of patients were still using Tecfidera at two years.

Tecfidera is rapidly eliminated from the body; the half-life of its active metabolite MMF is one hour meaning that no circulating MMF is present at 24 hours. However, side effects caused by Tecfidera, such as low lymphocyte counts, may persist until your body makes more white blood cells.