What is a common side effect of fingolimod (Gilenya)?

Fingolimod, marketed as Gilenya, is an oral medication commonly used to treat multiple sclerosis (MS). Among the potential side effects associated with fingolimod, headache is frequently reported by patients. This occurs due to various mechanisms, including the modulation of immune responses and effects on the CNS that the drug may exert as it alters lymphocyte circulation and affects various receptors.

While weight gain, insomnia, and severe nausea can occur with various medications, they are not as directly associated with fingolimod as headache is. Weight gain is typically not a common side effect and is more frequently linked to other types of MS treatments, insomnia can result from multiple factors, and severe nausea is not a predominant concern when patients are prescribed fingolimod. Thus, headache stands out as a more recognizable and common adverse effect of this specific medication.