Side effect profile and adherence to in the treatment of multiple sclerosis with interferon beta-1a.

This study examines the course of patient-reported side effects during the first 4 months of treatment for multiple sclerosis (MS) with interferon beta-1a (IFN beta-1a), and the relationship of those side effects to discontinuation of medication. Flu-like symptoms, muscle aches and chills decreased over the first 2 months of treatment but did not change over the second 2 months. Loss of feeling or numbness, tingling and depression increased over 4 months, however these side effects were generally mild. Loss of feeling or numbness and tingling at 2 month follow-up were significantly related to discontinuation of IFN beta-1a by 4 month follow-up.