Restless legs syndrome associated with teriflunomide use in two patients with multiple sclerosis

Teriflunomide is an oral agent that has long been used to treat relapsing-remitting multiple sclerosis. Teriflunomide inhibits the rapid proliferation of T and B lymphocytes by inhibiting the activity of dihydroorotate dehydrogenase. Common side effects include headache, alanine aminotransferase level elevation, hair thinning, and arthralgia. Cases of restless legs syndrome (RLS) associated with the use of teriflunomide have not been previously reported; however, RLS is more frequently observed in patients with multiple sclerosis (MS) than in healthy individuals. Herein, we present two patients with MS with low Expanded Disability Status Scale scores who developed RLS symptoms shortly after starting teriflunomide and whose complaints improved immediately after discontinuing the drug. These cases emphasize the need to consider RLS as a potential side effect of teriflunomide treatment in patients with MS, in whom RLS is more common.