Otezla (apremilast) is a medication used to treat certain autoimmune conditions, primarily psoriatic Arthritis and moderate to severe plaque psoriasis. It works by inhibiting an enzyme called phosphodiesterase 4 (PDE4), which helps reduce inflammation. Otezla is taken orally and is often prescribed for patients who have not responded well to other treatments. Common side effects may include diarrhea, nausea, and headache.