Interferon-beta injection site reactions in patients with multiple sclerosis.

Interferon-beta (IFNβ) is effective treatments for relapsing multiple sclerosis (MS). IFNβ treatment includes subcutaneous (SC) IFNβ-1b, intramuscular (IM) and SC IFNβ-1a, and SC pegylated IFNβ-1a (PEG-IFNβ-1a). PEG-IFNβ-1a offers the advantage of a prolonged duration of action with a less frequent administration (every 2 weeks) and a higher patient adherence. However, the use of SC interferons could be characterized by potential skin toxicity. Injection site reactions (ISRs), featured by erythema, edema, pain, and pruritus, are the most common adverse reactions. ISRs are mild or moderate in the vast majority of cases, but they can be severe enough to induce drug discontinuation. Therefore, it is very important to adopt strategies to minimize ISRs by proper patient education and counseling. These include rotation of injection sites, use of autoinjectors, use of medication at room temperature, cold compress, or local anesthetic cream before injection, early application of medium to high potency topical corticosteroids with gauze medication, and nonsteroidal anti-inflammatory drugs taken before and for 24 h after the injection.