Lymphocytic colitis in the setting of teriflunomide use for relapsing multiple sclerosis

Teriflunomide is an oral monotherapy used to treat relapsing multiple sclerosis. Although teriflunomide may be associated with gastrointestinal symptoms, these events are mild and self-limiting. We present a 39-year-old female who developed severe diarrhea and lost 20 pounds within 3 weeks of starting teriflunomide. Despite discontinuing teriflunomide and undergoing cholestyramine washout, her symptoms persisted. Celiac disease on genetic testing was positive, but no anti-transglutaminase and anti-endomysial antibodies were detected. She underwent colonoscopy and biopsy was consistent with lymphocytic colitis. Remission was achieved within days of starting budenoside. Our case describes a rare, but serious, gastrointestinal adverse event of teriflunomide.